Search Results

Search found 123 results on 5 pages for 'dml'.

Page 3/5 | < Previous Page | 1 2 3 4 5  | Next Page >

• MySQL Data Manipulation and Query Statements

  The Data Manipulation Language (DML) includes the major commands, INSERT, UPDATE, DELETE, and SELECT...INTO. Today's article focuses specifically on the uber-useful INSERT, UPDATE, DELETE, and SELECT statements.

  Read the article

• SQL SERVER – Query Hint – Contest Win Joes 2 Pros Combo (USD 198) – Day 1 of 5

  - by pinaldave

  August 2011 we ran a contest where every day we give away one book for an entire month. The contest had extreme success. Lots of people participated and lots of give away. I have received lots of questions if we are doing something similar this month. Absolutely, instead of running a contest a month long we are doing something more interesting. We are giving away USD 198 worth gift every day for this week. We are giving away Joes 2 Pros 5 Volumes (BOOK) SQL 2008 Development Certification Training Kit every day. One copy in India and One in USA. Total 2 of the giveaway (worth USD 198). All the gifts are sponsored from the Koenig Training Solution and Joes 2 Pros. The books are available here Amazon | Flipkart | Indiaplaza How to Win: Read the Question Read the Hints Answer the Quiz in Contact Form in following format Question Answer Name of the country (The contest is open for USA and India residents only) 2 Winners will be randomly selected announced on August 20th. Question of the Day: Which of the following queries will return dirty data? a) SELECT * FROM Table1 (READUNCOMMITED) b) SELECT * FROM Table1 (NOLOCK) c) SELECT * FROM Table1 (DIRTYREAD) d) SELECT * FROM Table1 (MYLOCK) Query Hints: BIG HINT POST Most SQL people know what a “Dirty Record” is. You might also call that an “Intermediate record”. In case this is new to you here is a very quick explanation. The simplest way to describe the steps of a transaction is to use an example of updating an existing record into a table. When the insert runs, SQL Server gets the data from storage, such as a hard drive, and loads it into memory and your CPU. The data in memory is changed and then saved to the storage device. Finally, a message is sent confirming the rows that were affected. For a very short period of time the update takes the data and puts it into memory (an intermediate state), not a permanent state. For every data change to a table there is a brief moment where the change is made in the intermediate state, but is not committed. During this time, any other DML statement needing that data waits until the lock is released. This is a safety feature so that SQL Server evaluates only official data. For every data change to a table there is a brief moment where the change is made in this intermediate state, but is not committed. During this time, any other DML statement (SELECT, INSERT, DELETE, UPDATE) needing that data must wait until the lock is released. This is a safety feature put in place so that SQL Server evaluates only official data. Additional Hints: I have previously discussed various concepts from SQL Server Joes 2 Pros Volume 1. SQL Joes 2 Pros Development Series – Dirty Records and Table Hints SQL Joes 2 Pros Development Series – Row Constructors SQL Joes 2 Pros Development Series – Finding un-matching Records SQL Joes 2 Pros Development Series – Efficient Query Writing Strategy SQL Joes 2 Pros Development Series – Finding Apostrophes in String and Text SQL Joes 2 Pros Development Series – Wildcard – Querying Special Characters SQL Joes 2 Pros Development Series – Wildcard Basics Recap Next Step: Answer the Quiz in Contact Form in following format Question Answer Name of the country (The contest is open for USA and India) Bonus Winner Leave a comment with your favorite article from the “additional hints” section and you may be eligible for surprise gift. There is no country restriction for this Bonus Contest. Do mention why you liked it any particular blog post and I will announce the winner of the same along with the main contest. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Joes 2 Pros, PostADay, SQL, SQL Authority, SQL Puzzle, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

  Read the article

• SQL Server and the XML Data Type : Data Manipulation

  The introduction of the xml data type, with its own set of methods for processing xml data, made it possible for SQL Server developers to create columns and variables of the type xml. Deanna Dicken examines the modify() method, which provides for data manipulation of the XML data stored in the xml data type via XML DML statements. Too many SQL Servers to keep up with?Download a free trial of SQL Response to monitor your SQL Servers in just one intuitive interface."The monitoringin SQL Response is excellent." Mike Towery.

  Read the article

• Online DATAFILE MOVE in Oracle Database 12c

  - by Ulrike Schwinn (DBA Community)

  Einige Operationen im Datenbankumfeld können nicht nur offline sondern auch online durchgeführt werden. Ein wichtiges Kennzeichen einer Online Operation ist dabei, dass Abfragen und DML Operationen während des Ablaufs der Operation (beispielsweise einer Reorganisation) ohne Unterbrechung weiter laufen können. Je nach einplanbarer Maintenance Zeit ist es daher durchaus wünschenswert, gewisse Operationen online durchzuführen. Generell gibt es in jedem Datenbankrelease einige Erweiterungen im Umfeld von Online Operationen. Besonders im aktuellen Release 12c gibt es eine Vielzahl neuer Operationen zu diesem Thema.Während der ersten 12c Veranstaltungen fand besonders das Kommando "DATAFILE ONLINE MOVE" besondere Aufmerksamkeit bei vielen Kunden. Aus diesem Grund wird im aktuellen Tipp dazu eine kleine Einführung gegeben.  Mehr dazu erfahren Sie hier. 

  Read the article

• ?????? ??????????! ?Bronze???? vol.4

  - by M.Morozumi

  ??????????????????????????????????????????????????????????????????? ???ORACLE MASTER Bronze Oracle Database 11g??????????????????????? ------------------------------- ????: Oracle Database 11g ???READ ONLY ?????????????????????????? ???????????????????????????1????????? a.?????????? DML ???????? b.?????????? SELECT ... FOR UPDATE ???????? c.??????? DROP ??????????? d.????????????????????ALTER TABLE ... READ WRITE ????????? ???????????????

  Read the article

• ?????? ??????????! ?Bronze???? vol.4 <??>

  - by M.Morozumi

  ???ORACLE MASTER Bronze Oracle Database 11g?????????????? ?????????????????????? ------------------------------- ????: Oracle Database 11g ???READ ONLY ?????????????????????????? ???????????????????????????1????????? a.?????????? DML ???????? b.?????????? SELECT ... FOR UPDATE ???????? c.??????? DROP ??????????? d.????????????????????ALTER TABLE ... READ WRITE ????????? ??????????????? ------------------------------- ??:c.??????? DROP ??????????? ??: ??????????? DROP ???????????????????????

  Read the article

• monitor table in data base

  - by hatem gamil

  hi all i want to make a web site to act as a monitor to a certain table in data base or act as a listenter on that table eg lets say i have table employees i want to make a web page that listen to changes occurs on that table (all DML operations) whenever a record is inserted i want this page alert me that a "1 row is inserted in table employee",or updated i want to get an alert " row number xx is updated" and so on so what is the best practise to do so thnx

  Read the article

• Database Testing

  - by vinoj123

  Can anyone expalin in detail how to perform Database Testing. I've basic idea about DDL, DML statements.

  Read the article

• drop down list binding

  - by John

  I have a table which has an Id and a name field. I usually bind the name to the dropdownlist but I was told that any dml should be on the Id so how can I use the name in the dropdownlist and at the same time still use the Id?

  Read the article

• Using Table-Valued Parameters in SQL Server

  - by Jesse

  I work with stored procedures in SQL Server pretty frequently and have often found myself with a need to pass in a list of values at run-time. Quite often this list contains a set of ids on which the stored procedure needs to operate the size and contents of which are not known at design time. In the past I’ve taken the collection of ids (which are usually integers), converted them to a string representation where each value is separated by a comma and passed that string into a VARCHAR parameter of a stored procedure. The body of the stored procedure would then need to parse that string into a table variable which could be easily consumed with set-based logic within the rest of the stored procedure. This approach works pretty well but the VARCHAR variable has always felt like an un-wanted “middle man” in this scenario. Of course, I could use a BULK INSERT operation to load the list of ids into a temporary table that the stored procedure could use, but that approach seems heavy-handed in situations where the list of values is usually going to contain only a few dozen values. Fortunately SQL Server 2008 introduced the concept of table-valued parameters which effectively eliminates the need for the clumsy middle man VARCHAR parameter. Example: Customer Transaction Summary Report Let’s say we have a report that can summarize the the transactions that we’ve conducted with customers over a period of time. The report returns a pretty simple dataset containing one row per customer with some key metrics about how much business that customer has conducted over the date range for which the report is being run. Sometimes the report is run for a single customer, sometimes it’s run for all customers, and sometimes it’s run for a handful of customers (i.e. a salesman runs it for the customers that fall into his sales territory). This report can be invoked from a website on-demand, or it can be scheduled for periodic delivery to certain users via SQL Server Reporting Services. Because the report can be created from different places and the query to generate the report is complex it’s been packed into a stored procedure that accepts three parameters: @startDate – The beginning of the date range for which the report should be run. @endDate – The end of the date range for which the report should be run. @customerIds – The customer Ids for which the report should be run. Obviously, the @startDate and @endDate parameters are DATETIME variables. The @customerIds parameter, however, needs to contain a list of the identity values (primary key) from the Customers table representing the customers that were selected for this particular run of the report. In prior versions of SQL Server we might have made this parameter a VARCHAR variable, but with SQL Server 2008 we can make it into a table-valued parameter. Defining And Using The Table Type In order to use a table-valued parameter, we first need to tell SQL Server about what the table will look like. We do this by creating a user defined type. For the purposes of this stored procedure we need a very simple type to model a table variable with a single integer column. We can create a generic type called ‘IntegerListTableType’ like this: CREATE TYPE IntegerListTableType AS TABLE (Value INT NOT NULL) Once defined, we can use this new type to define the @customerIds parameter in the signature of our stored procedure. The parameter list for the stored procedure definition might look like: 1: CREATE PROCEDURE dbo.rpt_CustomerTransactionSummary 2: @starDate datetime, 3: @endDate datetime, 4: @customerIds IntegerListTableTableType READONLY   Note the ‘READONLY’ statement following the declaration of the @customerIds parameter. SQL Server requires any table-valued parameter be marked as ‘READONLY’ and no DML (INSERT/UPDATE/DELETE) statements can be performed on a table-valued parameter within the routine in which it’s used. Aside from the DML restriction, however, you can do pretty much anything with a table-valued parameter as you could with a normal TABLE variable. With the user defined type and stored procedure defined as above, we could invoke like this: 1: DECLARE @cusomterIdList IntegerListTableType 2: INSERT @customerIdList VALUES (1) 3: INSERT @customerIdList VALUES (2) 4: INSERT @customerIdList VALUES (3) 5:  6: EXEC dbo.rpt_CustomerTransationSummary 7: @startDate = '2012-05-01', 8: @endDate = '2012-06-01' 9: @customerIds = @customerIdList   Note that we can simply declare a variable of type ‘IntegerListTableType’ just like any other normal variable and insert values into it just like a TABLE variable. We could also populate the variable with a SELECT … INTO or INSERT … SELECT statement if desired. Using The Table-Valued Parameter With ADO .NET Invoking a stored procedure with a table-valued parameter from ADO .NET is as simple as building a DataTable and passing it in as the Value of a SqlParameter. Here’s some example code for how we would construct the SqlParameter for the @customerIds parameter in our stored procedure: 1: var customerIdsParameter = new SqlParameter(); 2: customerIdParameter.Direction = ParameterDirection.Input; 3: customerIdParameter.TypeName = "IntegerListTableType"; 4: customerIdParameter.Value = selectedCustomerIds.ToIntegerListDataTable("Value");   All we’re doing here is new’ing up an instance of SqlParameter, setting the pamameters direction, specifying the name of the User Defined Type that this parameter uses, and setting its value. We’re assuming here that we have an IEnumerable<int> variable called ‘selectedCustomerIds’ containing all of the customer Ids for which the report should be run. The ‘ToIntegerListDataTable’ method is an extension method of the IEnumerable<int> type that looks like this: 1: public static DataTable ToIntegerListDataTable(this IEnumerable<int> intValues, string columnName) 2: { 3: var intergerListDataTable = new DataTable(); 4: intergerListDataTable.Columns.Add(columnName); 5: foreach(var intValue in intValues) 6: { 7: var nextRow = intergerListDataTable.NewRow(); 8: nextRow[columnName] = intValue; 9: intergerListDataTable.Rows.Add(nextRow); 10: } 11:  12: return intergerListDataTable; 13: }   Since the ‘IntegerListTableType’ has a single int column called ‘Value’, we pass that in for the ‘columnName’ parameter to the extension method. The method creates a new single-columned DataTable using the provided column name then iterates over the items in the IEnumerable<int> instance adding one row for each value. We can then use this SqlParameter instance when invoking the stored procedure just like we would use any other parameter. Advanced Functionality Using passing a list of integers into a stored procedure is a very simple usage scenario for the table-valued parameters feature, but I’ve found that it covers the majority of situations where I’ve needed to pass a collection of data for use in a query at run-time. I should note that BULK INSERT feature still makes sense for passing large amounts of data to SQL Server for processing. MSDN seems to suggest that 1000 rows of data is the tipping point where the overhead of a BULK INSERT operation can pay dividends. I should also note here that table-valued parameters can be used to deal with more complex data structures than single-columned tables of integers. A User Defined Type that backs a table-valued parameter can use things like identities and computed columns. That said, using some of these more advanced features might require the use the SqlDataRecord and SqlMetaData classes instead of a simple DataTable. Erland Sommarskog has a great article on his website that describes when and how to use these classes for table-valued parameters. What About Reporting Services? Earlier in the post I referenced the fact that our example stored procedure would be called from both a web application and a SQL Server Reporting Services report. Unfortunately, using table-valued parameters from SSRS reports can be a bit tricky and warrants its own blog post which I’ll be putting together and posting sometime in the near future.

  Read the article

• SQL SERVER – Weekly Series – Memory Lane – #034

  - by Pinal Dave

  Here is the list of selected articles of SQLAuthority.com across all these years. Instead of just listing all the articles I have selected a few of my most favorite articles and have listed them here with additional notes below it. Let me know which one of the following is your favorite article from memory lane. 2007 UDF – User Defined Function to Strip HTML – Parse HTML – No Regular Expression The UDF used in the blog does fantastic task – it scans entire HTML text and removes all the HTML tags. It keeps only valid text data without HTML task. This is one of the quite commonly requested tasks many developers have to face everyday. De-fragmentation of Database at Operating System to Improve Performance Operating system skips MDF file while defragging the entire filesystem of the operating system. It is absolutely fine and there is no impact of the same on performance. Read the entire blog post for my conversation with our network engineers. Delay Function – WAITFOR clause – Delay Execution of Commands How do you delay execution of the commands in SQL Server – ofcourse by using WAITFOR keyword. In this blog post, I explain the same with the help of T-SQL script. Find Length of Text Field To measure the length of TEXT fields the function is DATALENGTH(textfield). Len will not work for text field. As of SQL Server 2005, developers should migrate all the text fields to VARCHAR(MAX) as that is the way forward. Retrieve Current Date Time in SQL Server CURRENT_TIMESTAMP, GETDATE(), {fn NOW()} There are three ways to retrieve the current datetime in SQL SERVER. CURRENT_TIMESTAMP, GETDATE(), {fn NOW()} Explanation and Comparison of NULLIF and ISNULL An interesting observation is NULLIF returns null if it comparison is successful, whereas ISNULL returns not null if its comparison is successful. In one way they are opposite to each other. Here is my question to you - How to create infinite loop using NULLIF and ISNULL? If this is even possible? 2008 Introduction to SERVERPROPERTY and example SERVERPROPERTY is a very interesting system function. It returns many of the system values. I use it very frequently to get different server values like Server Collation, Server Name etc. SQL Server Start Time We can use DMV to find out what is the start time of SQL Server in 2008 and later version. In this blog you can see how you can do the same. Find Current Identity of Table Many times we need to know what is the current identity of the column. I have found one of my developers using aggregated function MAX () to find the current identity. However, I prefer following DBCC command to figure out current identity. Create Check Constraint on Column Some time we just need to create a simple constraint over the table but I have noticed that developers do many different things to make table column follow rules than just creating constraint. I suggest constraint is a very useful concept and every SQL Developer should pay good attention to this subject. 2009 List Schema Name and Table Name for Database This is one of the blog post where I straight forward display script. One of the kind of blog posts, which I still love to read and write. Clustered Index on Separate Drive From Table Location A table devoid of primary key index is called heap, and here data is not arranged in a particular order, which gives rise to issues that adversely affect performance. Data must be stored in some kind of order. If we put clustered index on it then the order will be forced by that index and the data will be stored in that particular order. Understanding Table Hints with Examples Hints are options and strong suggestions specified for enforcement by the SQL Server query processor on DML statements. The hints override any execution plan the query optimizer might select for a query. 2010 Data Pages in Buffer Pool – Data Stored in Memory Cache One of my earlier year article, which I still read it many times and point developers to read it again. It is clear from the Resultset that when more than one index is used, datapages related to both or all of the indexes are stored in Memory Cache separately. TRANSACTION, DML and Schema Locks Can you create a situation where you can see Schema Lock? Well, this is a very simple question, however during the interview I notice over 50 candidates failed to come up with the scenario. In this blog post, I have demonstrated the situation where we can see the schema lock in database. 2011 Solution – Puzzle – Statistics are not updated but are Created Once In this example I have created following situation: Create Table Insert 1000 Records Check the Statistics Now insert 10 times more 10,000 indexes Check the Statistics – it will be NOT updated Auto Update Statistics and Auto Create Statistics for database is TRUE Now I have requested two things in the example 1) Why this is happening? 2) How to fix this issue? Selecting Domain from Email Address This is a straight to script blog post where I explain how to select only domain name from entire email address. Solution – Generating Zero Without using Any Numbers in T-SQL How to get zero digit without using any digit? This is indeed a very interesting question and the answer is even interesting. Try to come up with answer in next 10 minutes and if you can’t come up with the answer the blog post read this post for solution. 2012 Simple Explanation and Puzzle with SOUNDEX Function and DIFFERENCE Function In simple words - SOUNDEX converts an alphanumeric string to a four-character code to find similar-sounding words or names. DIFFERENCE function returns an integer value. The  integer returned is the number of characters in the SOUNDEX values that are the same. Read Only Files and SQL Server Management Studio (SSMS) I have come across a very interesting feature in SSMS related to “Read Only” files. I believe it is a little unknown feature as well so decided to write a blog about the same. Identifying Column Data Type of uniqueidentifier without Querying System Tables How do I know if any table has a uniqueidentifier column and what is its value without using any DMV or System Catalogues? Only information you know is the table name and you are allowed to return any kind of error if the table does not have uniqueidentifier column. Read the blog post to find the answer. Solution – User Not Able to See Any User Created Object in Tables – Security and Permissions Issue Interesting question – “When I try to connect to SQL Server, it lets me connect just fine as well let me open and explore the database. I noticed that I do not see any user created instances but when my colleague attempts to connect to the server, he is able to explore the database as well see all the user created tables and other objects. Can you help me fix it?” Importing CSV File Into Database – SQL in Sixty Seconds #018 – Video Here is interesting small 60 second video on how to import CSV file into Database. ColumnStore Index – Batch Mode vs Row Mode Here is the logic behind when Columnstore Index uses Batch Mode and when it uses Row Mode. A batch typically represents about 1000 rows of data. Batch mode processing also uses algorithms that are optimized for the multicore CPUs and increased memory throughput. Follow up – Usage of $rowguid and $IDENTITY This is an excellent follow up blog post of my earlier blog post where I explain where to use $rowguid and $identity.  If you do not know the difference between them, this is a blog with a script example. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Memory Lane, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

  Read the article

• Do I need to disable access to a publisher database when setting up SQL Server 2000 Transactional Re

  - by Kev

  I have a production database i.e. where there are constant updates and I've configured this to be published to another server using Transactional Replication. When I configure transactional replication I've been doing the following: disable access to the source database backup source DB then restore to subscription server configure replication re-enable DB access to our apps The problem with this approach is scheduling in downtime, having to suspend all the various timed scheduled tasks we run and shutting down access to our various applications that are dependant on this database. Can I just configure transactional replication without disabling access to the publishing database and the subscriber database will correctly catch up? i.e. are all the DML statements queued on the publisher and as soon as the subscriber is ready they are picked off and executed?

  Read the article

• OWB 11gR2 - Windows and Linux 64-bit clients available

  - by David Allan

  In addition to the integrated release of OWB in the 11.2.0.3 Oracle database distribution, the following 64-bit standalone clients are now available for download from Oracle Support. OWB 11.2.0.3 Standalone client for Windows 64-bit - 13365470 OWB 11.2.0.3 Standalone client for Linux X86 64-bit - 13366327 This is in addition to the previously released 32-bit client on Windows. OWB 11.2.0.3 Standalone client for Windows 32-bit - 13365457 The support document Major OWB 11.2.0.3 New Features Summary has details for OWB 11.2.0.3 which include the following. Exadata v2 and oracle Database 11gR2 support capabilities; Support for Oracle Database 11gR2 and Exadata compression types Even more partitioning: Range-Range, Composite Hash/List, System, Reference Transparent Data Encryption support Data Guard support/certification Compiled PL/SQL code generation Capabilities to support data warehouse ETL best practices; Read and write Oracle Data Pump files with external tables External table preprocessor Partition specific DML Bulk data movement code templates: Oracle, IBM DB2, Microsoft SQL Server to Oracle Integration with Fusion Middleware capabilities; Support OWB's Control Center Agent on WLS Lots of interesting capabilities in 11.2.0.3 and the availability of the 64-bit client I'm sure is welcome news for many!

  Read the article

• Unified Auditing - Das neue Auditing in Oracle Database 12c

  - by Heinz-Wilhelm Fabry (DBA Community)

  In Datenbanken werden fast immer vor allem wichtige Informationen abgelegt. Der Zugriff darauf unterliegt in der Regel gesetzlichen oder betrieblichen Auflagen. Weil der Nachweis, dass diese Auflagen eingehalten werden, ausschliesslich über das Auditing möglich ist, ist eine Datenbank ohne Auditing eigentlich nicht vorstellbar. Ein Artikel der DBA Community hat sich bereits vor einiger Zeit mit den Möglichkeiten und Varianten des Auditierens in der Datenbankversion Oracle Database 11g beschäftigt. Der Artikel beschreibt das Auditing vom Default Auditing, mit dem zum Beispiel das Starten und Stoppen der Datenbank dokumentiert wird, bis hin zum Fine Grained Auditing (FGA), das sehr zielgerichtet DML Operationen erfasst. Er geht auch auf die unterschiedlichen Speichermöglichkeiten für die Audit Daten ein, auf die sogenannten audit trails: Neben der Variante, den audit trail in unterschiedlichen Tabellen der Datenbank (SYS.AUD$, SYS.FGA_LOG$, DVSYS.AUDIT_TRAIL$) abzulegen, wird dabei auf Betriebssystemdateien in einem Oracle proprietären oder im XML Format zurückgegriffen sowie auf die SYSLOGs oder EVENT LOGs der Betriebssysteme. Schaut man sich das alles an, kann man sicherlich feststellen, dass das Auditing über viele Jahre ständig an neue Anforderungen angepasst und erweitert wurde. Aber es ist damit auch nach und nach unübersichtlicher geworden. Das ist vor allem deshalb problematisch, weil das Ziel des Auditing nicht das unbegerenzte Sammeln von Informationen ist, sondern die Auswertung dieser Informationen. Darum wurden in der aktuellsten Datenbankversion, Oracle Database 12c, die unterschiedlichen audit trails zu einem einzigen audit trail zusammengeführt. Das Ergebnis wird als unified auditing bezeichnet. Die dazu nötige vollständige Überarbeitung der Architektur des Auditing Verfahrens bietet gleichzeitig die Gelegenheit, weitere Verbesserungen zu implementieren. Das betrifft sowohl die Performance als auch die Öffnung des gesamten Auditierens zur Nutzung durch diverse weitere Oracle Werkzeuge wie SQL*Loader und RMAN. Der folgende Artikel beschreibt, wie man das neue unified auditing einrichtet, wie man damit arbeitet und welche Vorteile es gegenüber dem 'alten' Auditing bietet Hier geht's zum Artikel.

  Read the article

• What the Hekaton?

  - by Tony Davis

  Hekaton, the power behind SQL Server 2014′s In-Memory OLTP technology, is intended to make data operations run orders of magnitude faster on SQL Server. This works its magic partly by serving database workloads entirely from main memory, using memory-optimized table structures. It replaces the relational engine’s standard locking model with an optimistic concurrency model based on time-stamped row versions. Deeper down the Hekaton engine uses new, ‘latch free’ data structures. So far, so good, but performance improvements on this scale require a compromise, and the compromise is that these aren’t tables as we understand them. For the database developer, these differences are painful because they involve sacrificing some very important bits of the relational model. Most importantly, Hekaton tables don’t currently support FOREIGN KEY constraints or CHECK constraints, and you can’t put the checks in triggers because there aren’t any DML triggers either. Constraints allow a relational designer to enforce relational integrity and data integrity. Without them, of course, ‘bad data’ can get into our Hekaton tables. There is no easy way of preventing it. For several classes of database and data, this is a show-stopper. One may regard all these restrictions regretfully, seeing limited opportunity to try out Hekaton with current databases, but perhaps there is also a sudden glow of recognition. Isn’t this how we all originally imagined table variables were going to be, back in SQL 2005? And they have much the same restrictions. Maybe, instead of pretending that a currently-designed database can be ‘Hekatonized’ with a few mouse clicks, we should redesign databases for SQL 2014 to replace table variables with Hekaton tables, exploiting this technology for fast intermediate processing, and for the most part forget, for now, the idea of trying to convert our base relational tables into Hekaton tables. Few database developers would be averse to having their working tables running an order of magnitude faster, as long as it didn’t compromise the integrity of the data in the base tables.

  Read the article

• Intelligent Conflict Detection and Resolution

  - by Doug Reid

  0 false 18 pt 18 pt 0 0 false false false /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-ascii-font-family:Cambria; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Cambria; mso-hansi-theme-font:minor-latin;} Conflict Detection and Resolution in Oracle GoldenGate11gR2 has gone through a significant overhaul. The improvements that have been made to this area are substantial and will make it easier for customers to implement complex, heterogeneous GoldenGate configurations. GoldenGate has provided methods for conflict detection and resolution for a number of past releases, but at Oracle we have the opportunity to take advantage of some of the great ideas in this area. Oracle has had feature rich conflict detection and resolution framework in other products, which has been implemented in Oracle GoldenGate 11gR2. These improvements are geared toward helping customers more easily implement advanced configurations that require conflict detection and resolution by providing a robust framework for conflict detection for all DML statements and resolution via pre-built methods, all with less code and simpler syntax than in prior releases. Conflict Detection and Resolution in Oracle GoldenGate 11gR2 is available for our supported heterogeneous platforms, which includes Oracle Database, MySQL, Sybase ASE, SQL Server, and DB2 Linux, Unix, Windows, z/OS, plus DB2 on i Series, which is newly supported in this release. Additional information on the Conflict Detection and Resolution capabilities can be found in our documentation. 

  Read the article

• Database Migration Scripts: Getting from place A to place B

  - by Phil Factor

  We’ll be looking at a typical database ‘migration’ script which uses an unusual technique to migrate existing ‘de-normalised’ data into a more correct form. So, the book-distribution business that uses the PUBS database has gradually grown organically, and has slipped into ‘de-normalisation’ habits. What’s this? A new column with a list of tags or ‘types’ assigned to books. Because books aren’t really in just one category, someone has ‘cured’ the mismatch between the database and the business requirements. This is fine, but it is now proving difficult for their new website that allows searches by tags. Any request for history book really has to look in the entire list of associated tags rather than the ‘Type’ field that only keeps the primary tag. We have other problems. The TypleList column has duplicates in there which will be affecting the reporting, and there is the danger of mis-spellings getting there. The reporting system can’t be persuaded to do reports based on the tags and the Database developers are complaining about the unCoddly things going on in their database. In your version of PUBS, this extra column doesn’t exist, so we’ve added it and put in 10,000 titles using SQL Data Generator. /* So how do we refactor this database? firstly, we create a table of all the tags. */IF  OBJECT_ID('TagName') IS NULL OR OBJECT_ID('TagTitle') IS NULL  BEGIN  CREATE TABLE  TagName (TagName_ID INT IDENTITY(1,1) PRIMARY KEY ,     Tag VARCHAR(20) NOT NULL UNIQUE)  /* ...and we insert into it all the tags from the list (remembering to take out any leading spaces */  INSERT INTO TagName (Tag)     SELECT DISTINCT LTRIM(x.y.value('.', 'Varchar(80)')) AS [Tag]     FROM     (SELECT  Title_ID,          CONVERT(XML, '<list><i>' + REPLACE(TypeList, ',', '</i><i>') + '</i></list>')          AS XMLkeywords          FROM   dbo.titles)g    CROSS APPLY XMLkeywords.nodes('/list/i/text()') AS x ( y )  /* we can then use this table to provide a table that relates tags to articles */  CREATE TABLE TagTitle   (TagTitle_ID INT IDENTITY(1, 1),   [title_id] [dbo].[tid] NOT NULL REFERENCES titles (Title_ID),   TagName_ID INT NOT NULL REFERENCES TagName (Tagname_ID)   CONSTRAINT [PK_TagTitle]       PRIMARY KEY CLUSTERED ([title_id] ASC, TagName_ID)       ON [PRIMARY])        CREATE NONCLUSTERED INDEX idxTagName_ID  ON  TagTitle (TagName_ID)  INCLUDE (TagTitle_ID,title_id)        /* ...and it is easy to fill this with the tags for each title ... */        INSERT INTO TagTitle (Title_ID, TagName_ID)    SELECT DISTINCT Title_ID, TagName_ID      FROM        (SELECT  Title_ID,          CONVERT(XML, '<list><i>' + REPLACE(TypeList, ',', '</i><i>') + '</i></list>')          AS XMLkeywords          FROM   dbo.titles)g    CROSS APPLY XMLkeywords.nodes('/list/i/text()') AS x ( y )    INNER JOIN TagName ON TagName.Tag=LTRIM(x.y.value('.', 'Varchar(80)'))    END    /* That's all there was to it. Now we can select all titles that have the military tag, just to try things out */SELECT Title FROM titles  INNER JOIN TagTitle ON titles.title_ID=TagTitle.Title_ID  INNER JOIN Tagname ON Tagname.TagName_ID=TagTitle.TagName_ID  WHERE tagname.tag='Military'/* and see the top ten most popular tags for titles */SELECT Tag, COUNT(*) FROM titles  INNER JOIN TagTitle ON titles.title_ID=TagTitle.Title_ID  INNER JOIN Tagname ON Tagname.TagName_ID=TagTitle.TagName_ID  GROUP BY Tag ORDER BY COUNT(*) DESC/* and if you still want your list of tags for each title, then here they are */SELECT title_ID, title, STUFF(  (SELECT ','+tagname.tag FROM titles thisTitle    INNER JOIN TagTitle ON titles.title_ID=TagTitle.Title_ID    INNER JOIN Tagname ON Tagname.TagName_ID=TagTitle.TagName_ID  WHERE ThisTitle.title_id=titles.title_ID  FOR XML PATH(''), TYPE).value('.', 'varchar(max)')  ,1,1,'')    FROM titles  ORDER BY title_ID So we’ve refactored our PUBS database without pain. We’ve even put in a check to prevent it being re-run once the new tables are created. Here is the diagram of the new tag relationship We’ve done both the DDL to create the tables and their associated components, and the DML to put the data in them. I could have also included the script to remove the de-normalised TypeList column, but I’d do a whole lot of tests first before doing that. Yes, I’ve left out the assertion tests too, which should check the edge cases and make sure the result is what you’d expect. One thing I can’t quite figure out is how to deal with an ordered list using this simple XML-based technique. We can ensure that, if we have to produce a list of tags, we can get the primary ‘type’ to be first in the list, but what if the entire order is significant? Thank goodness it isn’t in this case. If it were, we might have to revisit a string-splitter function that returns the ordinal position of each component in the sequence. You’ll see immediately that we can create a synchronisation script for deployment from a comparison tool such as SQL Compare, to change the schema (DDL). On the other hand, no tool could do the DML to stuff the data into the new table, since there is no way that any tool will be able to work out where the data should go. We used some pretty hairy code to deal with a slightly untypical problem. We would have to do this migration by hand, and it has to go into source control as a batch. If most of your database changes are to be deployed by an automated process, then there must be a way of over-riding this part of the data synchronisation process to do this part of the process taking the part of the script that fills the tables, Checking that the tables have not already been filled, and executing it as part of the transaction. Of course, you might prefer the approach I’ve taken with the script of creating the tables in the same batch as the data conversion process, and then using the presence of the tables to prevent the script from being re-run. The problem with scripting a refactoring change to a database is that it has to work both ways. If we install the new system and then have to rollback the changes, several books may have been added, or had their tags changed, in the meantime. Yes, you have to script any rollback! These have to be mercilessly tested, and put in source control just in case of the rollback of a deployment after it has been in place for any length of time. I’ve shown you how to do this with the part of the script .. /* and if you still want your list of tags for each title, then here they are */SELECT title_ID, title, STUFF(  (SELECT ','+tagname.tag FROM titles thisTitle    INNER JOIN TagTitle ON titles.title_ID=TagTitle.Title_ID    INNER JOIN Tagname ON Tagname.TagName_ID=TagTitle.TagName_ID  WHERE ThisTitle.title_id=titles.title_ID  FOR XML PATH(''), TYPE).value('.', 'varchar(max)')  ,1,1,'')    FROM titles  ORDER BY title_ID …which would be turned into an UPDATE … FROM script. UPDATE titles SET  typelist= ThisTaglistFROM     (SELECT title_ID, title, STUFF(    (SELECT ','+tagname.tag FROM titles thisTitle      INNER JOIN TagTitle ON titles.title_ID=TagTitle.Title_ID      INNER JOIN Tagname ON Tagname.TagName_ID=TagTitle.TagName_ID    WHERE ThisTitle.title_id=titles.title_ID    ORDER BY CASE WHEN tagname.tag=titles.[type] THEN 1 ELSE 0  END DESC    FOR XML PATH(''), TYPE).value('.', 'varchar(max)')    ,1,1,'')  AS ThisTagList  FROM titles)fINNER JOIN Titles ON f.title_ID=Titles.title_ID You’ll notice that it isn’t quite a round trip because the tags are in a different order, though we’ve managed to make sure that the primary tag is the first one as originally. So, we’ve improved the database for the poor book distributors using PUBS. It is not a major deal but you’ve got to be prepared to provide a migration script that will go both forwards and backwards. Ideally, database refactoring scripts should be able to go from any version to any other. Schema synchronization scripts can do this pretty easily, but no data synchronisation scripts can deal with serious refactoring jobs without the developers being able to specify how to deal with cases like this.

  Read the article

• How to query on table returned by Stored procedure within a procedure.

  - by Shantanu Gupta

  I have a stored procedure that is performing some ddl dml operations. It retrieves a data after processing data from CTE and cross apply and other such complex things. Now this returns me a 4 tables which gets binded to various sources at frontend. Now I want to use one of the table to further processing so as to get more usefull information from it. eg. This table would be containing approx 2000 records at most of which i want to get records that belongs to lodging only. PK_CATEGORY_ID DESCRIPTION FK_CATEGORY_ID IMMEDIATE_PARENT Department_ID Department_Name DESCRIPTION_HIERARCHY DEPTH IS_ACTIVE ID_PATH DESC_PATH -------------------- -------------------------------------------------- -------------------- -------------------------------------------------- -------------------- -------------------------------------------------- ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- ----------- ----------- ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- 1 Food NULL NULL 1 Food (Food) Food 0 1 0 Food 5 Chinese 1 Food 1 Food (Food) ----Chinese 1 1 1 Food->Chinese 14 X 5 Chinese 1 Food (Food) --------X 2 1 1->5 Food->Chinese->X 15 Y 5 Chinese 1 Food (Food) --------Y 2 1 1->5 Food->Chinese->Y 65 asdasd 5 Chinese 1 Food (Food) --------asdasd 2 1 1->5 Food->Chinese->asdasd 66 asdas 5 Chinese 1 Food (Food) --------asdas 2 1 1->5 Food->Chinese->asdas 8 Italian 1 Food 1 Food (Food) ----Italian 1 1 1 Food->Italian 48 hfghfgh 1 Food 1 Food (Food) ----hfghfgh 1 1 1 Food->hfghfgh 55 Asd 1 Food 1 Food (Food) ----Asd 1 1 1 Food->Asd 2 Lodging NULL NULL 2 Lodging (Lodging) Lodging 0 1 0 Lodging 3 Room 2 Lodging 2 Lodging (Lodging) ----Room 1 1 2 Lodging->Room 4 Floor 3 Room 2 Lodging (Lodging) --------Floor 2 1 2->3 Lodging->Room->Floor 9 First 4 Floor 2 Lodging (Lodging) ------------First 3 1 2->3->4 Lodging->Room->Floor->First 10 Second 4 Floor 2 Lodging (Lodging) ------------Second 3 1 2->3->4 Lodging->Room->Floor->Second 11 Third 4 Floor 2 Lodging (Lodging) ------------Third 3 1 2->3->4 Lodging->Room->Floor->Third 29 Fourth 4 Floor 2 Lodging (Lodging) ------------Fourth 3 1 2->3->4 Lodging->Room->Floor->Fourth 12 Air Conditioned 3 Room 2 Lodging (Lodging) --------Air Conditioned 2 1 2->3 Lodging->Room->Air Conditioned 20 With Balcony 12 Air Conditioned 2 Lodging (Lodging) ------------With Balcony 3 1 2->3->12 Lodging->Room->Air Conditioned->With Balcony 24 Mountain View 20 With Balcony 2 Lodging (Lodging) ----------------Mountain View 4 1 2->3->12->20 Lodging->Room->Air Conditioned->With Balcony->Mountain View 25 Ocean View 20 With Balcony 2 Lodging (Lodging) ----------------Ocean View 4 1 2->3->12->20 Lodging->Room->Air Conditioned->With Balcony->Ocean View 26 Garden View 20 With Balcony 2 Lodging (Lodging) ----------------Garden View 4 1 2->3->12->20 Lodging->Room->Air Conditioned->With Balcony->Garden View 52 Smoking 20 With Balcony 2 Lodging (Lodging) ----------------Smoking 4 1 2->3->12->20 Lodging->Room->Air Conditioned->With Balcony->Smoking 21 Without Balcony 12 Air Conditioned 2 Lodging (Lodging) ------------Without Balcony 3 1 2->3->12 Lodging->Room->Air Conditioned->Without Balcony 13 Non Air Conditioned 3 Room 2 Lodging (Lodging) --------Non Air Conditioned 2 1 2->3 Lodging->Room->Non Air Conditioned 22 With Balcony 13 Non Air Conditioned 2 Lodging (Lodging) ------------With Balcony 3 1 2->3->13 Lodging->Room->Non Air Conditioned->With Balcony 71 EA 3 Room 2 Lodging (Lodging) --------EA 2 1 2->3 Lodging->Room->EA 50 Casabellas 2 Lodging 2 Lodging (Lodging) ----Casabellas 1 1 2 Lodging->Casabellas 51 North Beach 50 Casabellas 2 Lodging (Lodging) --------North Beach 2 1 2->50 Lodging->Casabellas->North Beach 40 Fooding NULL NULL 40 Fooding (Fooding) Fooding 0 1 0 Fooding 41 Pizza 40 Fooding 40 Fooding (Fooding) ----Pizza 1 1 40 Fooding->Pizza 45 Onion 41 Pizza 40 Fooding (Fooding) --------Onion 2 1 40->41 Fooding->Pizza->Onion 47 Extra Cheeze 41 Pizza 40 Fooding (Fooding) --------Extra Cheeze 2 1 40->41 Fooding->Pizza->Extra Cheeze 77 Burger 40 Fooding 40 Fooding (Fooding) ----Burger 1 1 40 Fooding->Burger This result is being obtained to me using some stored procedure which contains some DML operations as well. i want something like this select description from exec spName where fk_category_id=5 Remember that this spName is returning me 4 tables of which i want to perform some query on one of the table whose index will be known to me. I dont have to send it to UI before querying further. I am using Sql Server 2008 but would like a compatible solution for 2005 also.

  Read the article

• The case of the phantom ADF developer (and other yarns)

  - by Chris Muir

  A few years of ADF experience means I see common mistakes made by different developers, some I regularly make myself.  This post is designed to assist beginners to Oracle JDeveloper Application Development Framework (ADF) avoid a common ADF pitfall, the case of the phantom ADF developer [add Scooby-Doo music here]. ADF Business Components - triggers, default table values and instead of views. Oracle's JDeveloper tutorials help with the A-B-Cs of ADF development, typically built on the nice 'n safe demo schema provided by with the Oracle database such as the HR demo schema. However it's not too long until ADF beginners, having built up some confidence from learning with the tutorials and vanilla demo schemas, start building ADF Business Components based upon their own existing database schema objects.  This is where unexpected problems can sneak in. The crime Developers may encounter a surprising error at runtime when editing a record they just created or updated and committed to the database, based on their own existing tables, namely the error: JBO-25014: Another user has changed the row with primary key oracle.jbo.Key[x] ...where X is the primary key value of the row at hand.  In a production environment with multiple users this error may be legit, one of the other users has updated the row since you queried it.  Yet in a development environment this error is just plain confusing.  If developers are isolated in their own database, creating and editing records they know other users can't possibly be working with, or all the other developers have gone home for the day, how is this error possible? There are no other users?  It must be the phantom ADF developer! [insert dramatic music here] The following picture is what you'll see in the Business Component Browser, and you'll receive a similar error message via an ADF Faces page: A false conclusion What can possibly cause this issue if it isn't our phantom ADF developer?  Doesn't ADF BC implement record locking, locking database records when the row is modified in the ADF middle-tier by a user?  How can our phantom ADF developer even take out a lock if this is the case?  Maybe ADF has a bug, maybe ADF isn't implementing record locking at all?  Shouldn't we see the error "JBO-26030: Failed to lock the record, another user holds the lock" as we attempt to modify the record, why do we see JBO-25014? : Let's verify that ADF is in fact issuing the correct SQL LOCK-FOR-UPDATE statement to the database. First we need to verify ADF's locking strategy.  It is determined by the Application Module's jbo.locking.mode property.  The default (as of JDev 11.1.1.4.0 if memory serves me correct) and recommended value is optimistic, and the other valid value is pessimistic. Next we need a mechanism to check that ADF is issuing the LOCK statements to the database.  We could ask DBAs to monitor locks with OEM, but optimally we'd rather not involve overworked DBAs in this process, so instead we can use the ADF runtime setting –Djbo.debugoutput=console.  At runtime this options turns on instrumentation within the ADF BC layer, which among a lot of extra detail displayed in the log window, will show the actual SQL statement issued to the database, including the LOCK statement we're looking to confirm. Setting our locking mode to pessimistic, opening the Business Components Browser of a JSF page allowing us to edit a record, say the CHARGEABLE field within a BOOKINGS record where BOOKING_NO = 1206, upon editing the record see among others the following log entries: [421] Built select: 'SELECT BOOKING_NO, EVENT_NO, RESOURCE_CODE, CHARGEABLE, MADE_BY, QUANTITY, COST, STATUS, COMMENTS FROM BOOKINGS Bookings'[422] Executing LOCK...SELECT BOOKING_NO, EVENT_NO, RESOURCE_CODE, CHARGEABLE, MADE_BY, QUANTITY, COST, STATUS, COMMENTS FROM BOOKINGS Bookings WHERE BOOKING_NO=:1 FOR UPDATE NOWAIT[423] Where binding param 1: 1206  As can be seen on line 422, in fact a LOCK-FOR-UPDATE is indeed issued to the database.  Later when we commit the record we see: [441] OracleSQLBuilder: SAVEPOINT 'BO_SP'[442] OracleSQLBuilder Executing, Lock 1 DML on: BOOKINGS (Update)[443] UPDATE buf Bookings>#u SQLStmtBufLen: 210, actual=62[444] UPDATE BOOKINGS Bookings SET CHARGEABLE=:1 WHERE BOOKING_NO=:2[445] Update binding param 1: N[446] Where binding param 2: 1206[447] BookingsView1 notify COMMIT ... [448] _LOCAL_VIEW_USAGE_model_Bookings_ResourceTypesView1 notify COMMIT ... [449] EntityCache close prepared statement ....and as a result the changes are saved to the database, and the lock is released. Let's see what happens when we use the optimistic locking mode, this time to change the same BOOKINGS record CHARGEABLE column again.  As soon as we edit the record we see little activity in the logs, nothing to indicate any SQL statement, let alone a LOCK has been taken out on the row. However when we save our records by issuing a commit, the following is recorded in the logs: [509] OracleSQLBuilder: SAVEPOINT 'BO_SP'[510] OracleSQLBuilder Executing doEntitySelect on: BOOKINGS (true)[511] Built select: 'SELECT BOOKING_NO, EVENT_NO, RESOURCE_CODE, CHARGEABLE, MADE_BY, QUANTITY, COST, STATUS, COMMENTS FROM BOOKINGS Bookings'[512] Executing LOCK...SELECT BOOKING_NO, EVENT_NO, RESOURCE_CODE, CHARGEABLE, MADE_BY, QUANTITY, COST, STATUS, COMMENTS FROM BOOKINGS Bookings WHERE BOOKING_NO=:1 FOR UPDATE NOWAIT[513] Where binding param 1: 1205[514] OracleSQLBuilder Executing, Lock 2 DML on: BOOKINGS (Update)[515] UPDATE buf Bookings>#u SQLStmtBufLen: 210, actual=62[516] UPDATE BOOKINGS Bookings SET CHARGEABLE=:1 WHERE BOOKING_NO=:2[517] Update binding param 1: Y[518] Where binding param 2: 1205[519] BookingsView1 notify COMMIT ... [520] _LOCAL_VIEW_USAGE_model_Bookings_ResourceTypesView1 notify COMMIT ... [521] EntityCache close prepared statement Again even though we're seeing the midtier delay the LOCK statement until commit time, it is in fact occurring on line 412, and released as part of the commit issued on line 419.  Therefore with either optimistic or pessimistic locking a lock is indeed issued. Our conclusion at this point must be, unless there's the unlikely cause the LOCK statement is never really hitting the database, or the even less likely cause the database has a bug, then ADF does in fact take out a lock on the record before allowing the current user to update it.  So there's no way our phantom ADF developer could even modify the record if he tried without at least someone receiving a lock error. Hmm, we can only conclude the locking mode is a red herring and not the true cause of our problem.  Who is the phantom? At this point we'll need to conclude that the error message "JBO-25014: Another user has changed" is somehow legit, even though we don't understand yet what's causing it. This leads onto two further questions, how does ADF know another user has changed the row, and what's been changed anyway? To answer the first question, how does ADF know another user has changed the row, the Fusion Guide's section 4.10.11 How to Protect Against Losing Simultaneous Updated Data , that details the Entity Object Change-Indicator property, gives us the answer: At runtime the framework provides automatic "lost update" detection for entity objects to ensure that a user cannot unknowingly modify data that another user has updated and committed in the meantime. Typically, this check is performed by comparing the original values of each persistent entity attribute against the corresponding current column values in the database at the time the underlying row is locked. Before updating a row, the entity object verifies that the row to be updated is still consistent with the current state of the database.  The guide further suggests to make this solution more efficient: You can make the lost update detection more efficient by identifying any attributes of your entity whose values you know will be updated whenever the entity is modified. Typical candidates include a version number column or an updated date column in the row.....To detect whether the row has been modified since the user queried it in the most efficient way, select the Change Indicator option to compare only the change-indicator attribute values. We now know that ADF BC doesn't use the locking mechanism at all to protect the current user against updates, but rather it keeps a copy of the original record fetched, separate to the user changed version of the record, and it compares the original record against the one in the database when the lock is taken out.  If values don't match, be it the default compare-all-columns behaviour, or the more efficient Change Indicator mechanism, ADF BC will throw the JBO-25014 error. This leaves one last question.  Now we know the mechanism under which ADF identifies a changed row, what we don't know is what's changed and who changed it? The real culprit What's changed?  We know the record in the mid-tier has been changed by the user, however ADF doesn't use the changed record in the mid-tier to compare to the database record, but rather a copy of the original record before it was changed.  This leaves us to conclude the database record has changed, but how and by who? There are three potential causes: Database triggers The database trigger among other uses, can be configured to fire PLSQL code on a database table insert, update or delete.  In particular in an insert or update the trigger can override the value assigned to a particular column.  The trigger execution is actioned by the database on behalf of the user initiating the insert or update action. Why this causes the issue specific to our ADF use, is when we insert or update a record in the database via ADF, ADF keeps a copy of the record written to the database.  However the cached record is instantly out of date as the database triggers have modified the record that was actually written to the database.  Thus when we update the record we just inserted or updated for a second time to the database, ADF compares its original copy of the record to that in the database, and it detects the record has been changed – giving us JBO-25014. This is probably the most common cause of this problem. Default values A second reason this issue can occur is another database feature, default column values.  When creating a database table the schema designer can define default values for specific columns.  For example a CREATED_BY column could be set to SYSDATE, or a flag column to Y or N.  Default values are only used by the database when a user inserts a new record and the specific column is assigned NULL.  The database in this case will overwrite the column with the default value. As per the database trigger section, it then becomes apparent why ADF chokes on this feature, though it can only specifically occur in an insert-commit-update-commit scenario, not the update-commit-update-commit scenario. Instead of trigger views I must admit I haven't double checked this scenario but it seems plausible, that of the Oracle database's instead of trigger view (sometimes referred to as instead of views).  A view in the database is based on a query, and dependent on the queries complexity, may support insert, update and delete functionality to a limited degree.  In order to support fully insertable, updateable and deletable views, Oracle introduced the instead of view, that gives the view designer the ability to not only define the view query, but a set of programmatic PLSQL triggers where the developer can define their own logic for inserts, updates and deletes. While this provides the database programmer a very powerful feature, it can cause issues for our ADF application.  On inserting or updating a record in the instead of view, the record and it's data that goes in is not necessarily the data that comes out when ADF compares the records, as the view developer has the option to practically do anything with the incoming data, including throwing it away or pushing it to tables which aren't used by the view underlying query for fetching the data. Readers are at this point reminded that this article is specifically about how the JBO-25014 error occurs in the context of 1 developer on an isolated database.  The article is not considering how the error occurs in a production environment where there are multiple users who can cause this error in a legitimate fashion.  Assuming none of the above features are the cause of the problem, and optimistic locking is turned on (this error is not possible if pessimistic locking is the default mode *and* none of the previous causes are possible), JBO-25014 is quite feasible in a production ADF application if 2 users modify the same record. At this point under project timelines pressure, the obvious fix for developers is to drop both database triggers and default values from the underlying tables.  However we must be careful that these legacy constructs aren't used and assumed to be in place by other legacy systems.  Dropping the database triggers or default value that the existing Oracle Forms  applications assumes and requires to be in place could cause unexpected behaviour and bugs in the Forms application.  Proficient software engineers would recognize such a change may require a partial or full regression test of the existing legacy system, a potentially costly and timely exercise, not ideal. Solving the mystery once and for all Luckily ADF has built in functionality to deal with this issue, though it's not a surprise, as Oracle as the author of ADF also built the database, and are fully aware of the Oracle database's feature set.  At the Entity Object attribute level, the Refresh After Insert and Refresh After Update properties.  Simply selecting these instructs ADF BC after inserting or updating a record to the database, to expect the database to modify the said attributes, and read a copy of the changed attributes back into its cached mid-tier record.  Thus next time the developer modifies the current record, the comparison between the mid-tier record and the database record match, and JBO-25014: Another user has changed" is no longer an issue. [Post edit - as per the comment from Oracle's Steven Davelaar below, as he correctly points out the above solution will not work for instead-of-triggers views as it relies on SQL RETURNING clause which is incompatible with this type of view] Alternatively you can set the Change Indicator on one of the attributes.  This will work as long as the relating column for the attribute in the database itself isn't inadvertently updated.  In turn you're possibly just masking the issue rather than solving it, because if another developer turns the Change Indicator back on the original issue will return.

  Read the article

• Convert from Procedural to Object Oriented Code

  - by Anthony

  I have been reading Working Effectively with Legacy Code and Clean Code with the goal of learning strategies on how to begin cleaning up the existing code-base of a large ASP.NET webforms application. This system has been around since 2005 and since then has undergone a number of enhancements. Originally the code was structured as follows (and is still largely structured this way): ASP.NET (aspx/ascx) Code-behind (c#) Business Logic Layer (c#) Data Access Layer (c#) Database (Oracle) The main issue is that the code is procedural masquerading as object-oriented. It virtually violates all of the guidelines described in both books. This is an example of a typical class in the Business Logic Layer: public class AddressBO { public TransferObject GetAddress(string addressID) { if (StringUtils.IsNull(addressID)) { throw new ValidationException("Address ID must be entered"); } AddressDAO addressDAO = new AddressDAO(); return addressDAO.GetAddress(addressID); } public TransferObject Insert(TransferObject addressDetails) { if (StringUtils.IsNull(addressDetails.GetString("EVENT_ID")) || StringUtils.IsNull(addressDetails.GetString("LOCALITY")) || StringUtils.IsNull(addressDetails.GetString("ADDRESS_TARGET")) || StringUtils.IsNull(addressDetails.GetString("ADDRESS_TYPE_CODE")) || StringUtils.IsNull(addressDetails.GetString("CREATED_BY"))) { throw new ValidationException( "You must enter an Event ID, Locality, Address Target, Address Type Code and Created By."); } string addressID = Sequence.GetNextValue("ADDRESS_ID_SEQ"); addressDetails.SetValue("ADDRESS_ID", addressID); string syncID = Sequence.GetNextValue("SYNC_ID_SEQ"); addressDetails.SetValue("SYNC_ADDRESS_ID", syncID); TransferObject syncDetails = new TransferObject(); Transaction transaction = new Transaction(); try { AddressDAO addressDAO = new AddressDAO(); addressDAO.Insert(addressDetails, transaction); // insert the record for the target TransferObject addressTargetDetails = new TransferObject(); switch (addressDetails.GetString("ADDRESS_TARGET")) { case "PARTY_ADDRESSES": { addressTargetDetails.SetValue("ADDRESS_ID", addressID); addressTargetDetails.SetValue("ADDRESS_TYPE_CODE", addressDetails.GetString("ADDRESS_TYPE_CODE")); addressTargetDetails.SetValue("PARTY_ID", addressDetails.GetString("PARTY_ID")); addressTargetDetails.SetValue("EVENT_ID", addressDetails.GetString("EVENT_ID")); addressTargetDetails.SetValue("CREATED_BY", addressDetails.GetString("CREATED_BY")); addressDAO.InsertPartyAddress(addressTargetDetails, transaction); break; } case "PARTY_CONTACT_ADDRESSES": { addressTargetDetails.SetValue("ADDRESS_ID", addressID); addressTargetDetails.SetValue("ADDRESS_TYPE_CODE", addressDetails.GetString("ADDRESS_TYPE_CODE")); addressTargetDetails.SetValue("PUBLIC_RELEASE_FLAG", addressDetails.GetString("PUBLIC_RELEASE_FLAG")); addressTargetDetails.SetValue("CONTACT_ID", addressDetails.GetString("CONTACT_ID")); addressTargetDetails.SetValue("EVENT_ID", addressDetails.GetString("EVENT_ID")); addressTargetDetails.SetValue("CREATED_BY", addressDetails.GetString("CREATED_BY")); addressDAO.InsertContactAddress(addressTargetDetails, transaction); break; } << many more cases here >> default: { break; } } // synchronise SynchronisationBO synchronisationBO = new SynchronisationBO(); syncDetails = synchronisationBO.Synchronise("I", transaction, "ADDRESSES", addressDetails.GetString("ADDRESS_TARGET"), addressDetails, addressTargetDetails); // commit transaction.Commit(); } catch (Exception) { transaction.Rollback(); throw; } return new TransferObject("ADDRESS_ID", addressID, "SYNC_DETAILS", syncDetails); } << many more methods are here >> } It has a lot of duplication, the class has a number of responsibilities, etc, etc - it is just generally 'un-clean' code. All of the code throughout the system is dependent on concrete implementations. This is an example of a typical class in the Data Access Layer: public class AddressDAO : GenericDAO { public static readonly string BASE_SQL_ADDRESSES = "SELECT " + " a.address_id, " + " a.event_id, " + " a.flat_unit_type_code, " + " fut.description as flat_unit_description, " + " a.flat_unit_num, " + " a.floor_level_code, " + " fl.description as floor_level_description, " + " a.floor_level_num, " + " a.building_name, " + " a.lot_number, " + " a.street_number, " + " a.street_name, " + " a.street_type_code, " + " st.description as street_type_description, " + " a.street_suffix_code, " + " ss.description as street_suffix_description, " + " a.postal_delivery_type_code, " + " pdt.description as postal_delivery_description, " + " a.postal_delivery_num, " + " a.locality, " + " a.state_code, " + " s.description as state_description, " + " a.postcode, " + " a.country, " + " a.lock_num, " + " a.created_by, " + " TO_CHAR(a.created_datetime, '" + SQL_DATETIME_FORMAT + "') as created_datetime, " + " a.last_updated_by, " + " TO_CHAR(a.last_updated_datetime, '" + SQL_DATETIME_FORMAT + "') as last_updated_datetime, " + " a.sync_address_id, " + " a.lat," + " a.lon, " + " a.validation_confidence, " + " a.validation_quality, " + " a.validation_status " + "FROM ADDRESSES a, FLAT_UNIT_TYPES fut, FLOOR_LEVELS fl, STREET_TYPES st, " + " STREET_SUFFIXES ss, POSTAL_DELIVERY_TYPES pdt, STATES s " + "WHERE a.flat_unit_type_code = fut.flat_unit_type_code(+) " + "AND a.floor_level_code = fl.floor_level_code(+) " + "AND a.street_type_code = st.street_type_code(+) " + "AND a.street_suffix_code = ss.street_suffix_code(+) " + "AND a.postal_delivery_type_code = pdt.postal_delivery_type_code(+) " + "AND a.state_code = s.state_code(+) "; public TransferObject GetAddress(string addressID) { //Build the SELECT Statement StringBuilder selectStatement = new StringBuilder(BASE_SQL_ADDRESSES); //Add WHERE condition selectStatement.Append(" AND a.address_id = :addressID"); ArrayList parameters = new ArrayList{DBUtils.CreateOracleParameter("addressID", OracleDbType.Decimal, addressID)}; // Execute the SELECT statement Query query = new Query(); DataSet results = query.Execute(selectStatement.ToString(), parameters); // Check if 0 or more than one rows returned if (results.Tables[0].Rows.Count == 0) { throw new NoDataFoundException(); } if (results.Tables[0].Rows.Count > 1) { throw new TooManyRowsException(); } // Return a TransferObject containing the values return new TransferObject(results); } public void Insert(TransferObject insertValues, Transaction transaction) { // Store Values string addressID = insertValues.GetString("ADDRESS_ID"); string syncAddressID = insertValues.GetString("SYNC_ADDRESS_ID"); string eventID = insertValues.GetString("EVENT_ID"); string createdBy = insertValues.GetString("CREATED_BY"); // postal delivery string postalDeliveryTypeCode = insertValues.GetString("POSTAL_DELIVERY_TYPE_CODE"); string postalDeliveryNum = insertValues.GetString("POSTAL_DELIVERY_NUM"); // unit/building string flatUnitTypeCode = insertValues.GetString("FLAT_UNIT_TYPE_CODE"); string flatUnitNum = insertValues.GetString("FLAT_UNIT_NUM"); string floorLevelCode = insertValues.GetString("FLOOR_LEVEL_CODE"); string floorLevelNum = insertValues.GetString("FLOOR_LEVEL_NUM"); string buildingName = insertValues.GetString("BUILDING_NAME"); // street string lotNumber = insertValues.GetString("LOT_NUMBER"); string streetNumber = insertValues.GetString("STREET_NUMBER"); string streetName = insertValues.GetString("STREET_NAME"); string streetTypeCode = insertValues.GetString("STREET_TYPE_CODE"); string streetSuffixCode = insertValues.GetString("STREET_SUFFIX_CODE"); // locality/state/postcode/country string locality = insertValues.GetString("LOCALITY"); string stateCode = insertValues.GetString("STATE_CODE"); string postcode = insertValues.GetString("POSTCODE"); string country = insertValues.GetString("COUNTRY"); // esms address string esmsAddress = insertValues.GetString("ESMS_ADDRESS"); //address/GPS string lat = insertValues.GetString("LAT"); string lon = insertValues.GetString("LON"); string zoom = insertValues.GetString("ZOOM"); //string validateDate = insertValues.GetString("VALIDATED_DATE"); string validatedBy = insertValues.GetString("VALIDATED_BY"); string confidence = insertValues.GetString("VALIDATION_CONFIDENCE"); string status = insertValues.GetString("VALIDATION_STATUS"); string quality = insertValues.GetString("VALIDATION_QUALITY"); // the insert statement StringBuilder insertStatement = new StringBuilder("INSERT INTO ADDRESSES ("); StringBuilder valuesStatement = new StringBuilder("VALUES ("); ArrayList parameters = new ArrayList(); // build the insert statement insertStatement.Append("ADDRESS_ID, EVENT_ID, CREATED_BY, CREATED_DATETIME, LOCK_NUM "); valuesStatement.Append(":addressID, :eventID, :createdBy, SYSDATE, 1 "); parameters.Add(DBUtils.CreateOracleParameter("addressID", OracleDbType.Decimal, addressID)); parameters.Add(DBUtils.CreateOracleParameter("eventID", OracleDbType.Decimal, eventID)); parameters.Add(DBUtils.CreateOracleParameter("createdBy", OracleDbType.Varchar2, createdBy)); // build the insert statement if (!StringUtils.IsNull(syncAddressID)) { insertStatement.Append(", SYNC_ADDRESS_ID"); valuesStatement.Append(", :syncAddressID"); parameters.Add(DBUtils.CreateOracleParameter("syncAddressID", OracleDbType.Decimal, syncAddressID)); } if (!StringUtils.IsNull(postalDeliveryTypeCode)) { insertStatement.Append(", POSTAL_DELIVERY_TYPE_CODE"); valuesStatement.Append(", :postalDeliveryTypeCode "); parameters.Add(DBUtils.CreateOracleParameter("postalDeliveryTypeCode", OracleDbType.Varchar2, postalDeliveryTypeCode)); } if (!StringUtils.IsNull(postalDeliveryNum)) { insertStatement.Append(", POSTAL_DELIVERY_NUM"); valuesStatement.Append(", :postalDeliveryNum "); parameters.Add(DBUtils.CreateOracleParameter("postalDeliveryNum", OracleDbType.Varchar2, postalDeliveryNum)); } if (!StringUtils.IsNull(flatUnitTypeCode)) { insertStatement.Append(", FLAT_UNIT_TYPE_CODE"); valuesStatement.Append(", :flatUnitTypeCode "); parameters.Add(DBUtils.CreateOracleParameter("flatUnitTypeCode", OracleDbType.Varchar2, flatUnitTypeCode)); } if (!StringUtils.IsNull(lat)) { insertStatement.Append(", LAT"); valuesStatement.Append(", :lat "); parameters.Add(DBUtils.CreateOracleParameter("lat", OracleDbType.Decimal, lat)); } if (!StringUtils.IsNull(lon)) { insertStatement.Append(", LON"); valuesStatement.Append(", :lon "); parameters.Add(DBUtils.CreateOracleParameter("lon", OracleDbType.Decimal, lon)); } if (!StringUtils.IsNull(zoom)) { insertStatement.Append(", ZOOM"); valuesStatement.Append(", :zoom "); parameters.Add(DBUtils.CreateOracleParameter("zoom", OracleDbType.Decimal, zoom)); } if (!StringUtils.IsNull(flatUnitNum)) { insertStatement.Append(", FLAT_UNIT_NUM"); valuesStatement.Append(", :flatUnitNum "); parameters.Add(DBUtils.CreateOracleParameter("flatUnitNum", OracleDbType.Varchar2, flatUnitNum)); } if (!StringUtils.IsNull(floorLevelCode)) { insertStatement.Append(", FLOOR_LEVEL_CODE"); valuesStatement.Append(", :floorLevelCode "); parameters.Add(DBUtils.CreateOracleParameter("floorLevelCode", OracleDbType.Varchar2, floorLevelCode)); } if (!StringUtils.IsNull(floorLevelNum)) { insertStatement.Append(", FLOOR_LEVEL_NUM"); valuesStatement.Append(", :floorLevelNum "); parameters.Add(DBUtils.CreateOracleParameter("floorLevelNum", OracleDbType.Varchar2, floorLevelNum)); } if (!StringUtils.IsNull(buildingName)) { insertStatement.Append(", BUILDING_NAME"); valuesStatement.Append(", :buildingName "); parameters.Add(DBUtils.CreateOracleParameter("buildingName", OracleDbType.Varchar2, buildingName)); } if (!StringUtils.IsNull(lotNumber)) { insertStatement.Append(", LOT_NUMBER"); valuesStatement.Append(", :lotNumber "); parameters.Add(DBUtils.CreateOracleParameter("lotNumber", OracleDbType.Varchar2, lotNumber)); } if (!StringUtils.IsNull(streetNumber)) { insertStatement.Append(", STREET_NUMBER"); valuesStatement.Append(", :streetNumber "); parameters.Add(DBUtils.CreateOracleParameter("streetNumber", OracleDbType.Varchar2, streetNumber)); } if (!StringUtils.IsNull(streetName)) { insertStatement.Append(", STREET_NAME"); valuesStatement.Append(", :streetName "); parameters.Add(DBUtils.CreateOracleParameter("streetName", OracleDbType.Varchar2, streetName)); } if (!StringUtils.IsNull(streetTypeCode)) { insertStatement.Append(", STREET_TYPE_CODE"); valuesStatement.Append(", :streetTypeCode "); parameters.Add(DBUtils.CreateOracleParameter("streetTypeCode", OracleDbType.Varchar2, streetTypeCode)); } if (!StringUtils.IsNull(streetSuffixCode)) { insertStatement.Append(", STREET_SUFFIX_CODE"); valuesStatement.Append(", :streetSuffixCode "); parameters.Add(DBUtils.CreateOracleParameter("streetSuffixCode", OracleDbType.Varchar2, streetSuffixCode)); } if (!StringUtils.IsNull(locality)) { insertStatement.Append(", LOCALITY"); valuesStatement.Append(", :locality"); parameters.Add(DBUtils.CreateOracleParameter("locality", OracleDbType.Varchar2, locality)); } if (!StringUtils.IsNull(stateCode)) { insertStatement.Append(", STATE_CODE"); valuesStatement.Append(", :stateCode"); parameters.Add(DBUtils.CreateOracleParameter("stateCode", OracleDbType.Varchar2, stateCode)); } if (!StringUtils.IsNull(postcode)) { insertStatement.Append(", POSTCODE"); valuesStatement.Append(", :postcode "); parameters.Add(DBUtils.CreateOracleParameter("postcode", OracleDbType.Varchar2, postcode)); } if (!StringUtils.IsNull(country)) { insertStatement.Append(", COUNTRY"); valuesStatement.Append(", :country "); parameters.Add(DBUtils.CreateOracleParameter("country", OracleDbType.Varchar2, country)); } if (!StringUtils.IsNull(esmsAddress)) { insertStatement.Append(", ESMS_ADDRESS"); valuesStatement.Append(", :esmsAddress "); parameters.Add(DBUtils.CreateOracleParameter("esmsAddress", OracleDbType.Varchar2, esmsAddress)); } if (!StringUtils.IsNull(validatedBy)) { insertStatement.Append(", VALIDATED_DATE"); valuesStatement.Append(", SYSDATE "); insertStatement.Append(", VALIDATED_BY"); valuesStatement.Append(", :validatedBy "); parameters.Add(DBUtils.CreateOracleParameter("validatedBy", OracleDbType.Varchar2, validatedBy)); } if (!StringUtils.IsNull(confidence)) { insertStatement.Append(", VALIDATION_CONFIDENCE"); valuesStatement.Append(", :confidence "); parameters.Add(DBUtils.CreateOracleParameter("confidence", OracleDbType.Decimal, confidence)); } if (!StringUtils.IsNull(status)) { insertStatement.Append(", VALIDATION_STATUS"); valuesStatement.Append(", :status "); parameters.Add(DBUtils.CreateOracleParameter("status", OracleDbType.Varchar2, status)); } if (!StringUtils.IsNull(quality)) { insertStatement.Append(", VALIDATION_QUALITY"); valuesStatement.Append(", :quality "); parameters.Add(DBUtils.CreateOracleParameter("quality", OracleDbType.Decimal, quality)); } // finish off the statement insertStatement.Append(") "); valuesStatement.Append(")"); // build the insert statement string sql = insertStatement + valuesStatement.ToString(); // Execute the INSERT Statement Dml dmlDAO = new Dml(); int rowsAffected = dmlDAO.Execute(sql, transaction, parameters); if (rowsAffected == 0) { throw new NoRowsAffectedException(); } } << many more methods go here >> } This system was developed by me and a small team back in 2005 after a 1 week .NET course. Before than my experience was in client-server applications. Over the past 5 years I've come to recognise the benefits of automated unit testing, automated integration testing and automated acceptance testing (using Selenium or equivalent) but the current code-base seems impossible to introduce these concepts. We are now starting to work on a major enhancement project with tight time-frames. The team consists of 5 .NET developers - 2 developers with a few years of .NET experience and 3 others with little or no .NET experience. None of the team (including myself) has experience in using .NET unit testing or mocking frameworks. What strategy would you use to make this code cleaner, more object-oriented, testable and maintainable?

  Read the article

• PreparedStatement

  - by Steel Plume

  Hello, in the case of using PreparedStatement with a single common connection without any pool, can I recreate an instance for every dml/sql operation mantaining the power of prepared statements? I mean: for (int i=0; i<1000; i++) { PreparedStatement preparedStatement = connection.prepareStatement(sql); preparedStatement.setObject(1, someValue); preparedStatement.executeQuery(); preparedStatement.close(); } instead of: PreparedStatement preparedStatement = connection.prepareStatement(sql); for (int i=0; i<1000; i++) { preparedStatement.clearParameters(); preparedStatement.setObject(1, someValue); preparedStatement.executeQuery(); } preparedStatement.close(); my question arises by the fact that I want to put this code into a multithreaded environment, can you give me some advice? thanks

  Read the article

• Reusing a PreparedStatement multiple times

  - by Steel Plume

  Hello, in the case of using PreparedStatement with a single common connection without any pool, can I recreate an instance for every dml/sql operation mantaining the power of prepared statements? I mean: for (int i=0; i<1000; i++) { PreparedStatement preparedStatement = connection.prepareStatement(sql); preparedStatement.setObject(1, someValue); preparedStatement.executeQuery(); preparedStatement.close(); } instead of: PreparedStatement preparedStatement = connection.prepareStatement(sql); for (int i=0; i<1000; i++) { preparedStatement.clearParameters(); preparedStatement.setObject(1, someValue); preparedStatement.executeQuery(); } preparedStatement.close(); my question arises by the fact that I want to put this code into a multithreaded environment, can you give me some advice? thanks

  Read the article

• How to export more than 1MB in XML format using sqlcmd and without an input file?

  - by jon

  Hello, In SQL Server 2008, I want to export the result of a stored procedure to a file using sqlcmd utility. Now the end of my stored procedure is a select statement with a "for xml path.." clause at the end. I read on BOL that if I don't want my output truncated when reaching 1MB file size, I have to use this :XML ON command, but it should be placed on its own line, before calling the stored procedure. Does any of you experts know if it is possible to do that without specifying an input file for sqlcmd? (I'm calling sqlcmd like this: exec master..xp_cmdshell 'sqlcmd -Q"exec storedProcedureName @param1=value1, @param2=value2" -o c:\exportResults.xml -h-1 -E', but "storedProcedureName" and its parameters can change, which would mean 1 input file per passed parameters to sqlcmd) Also, it seems that I can't use bcp instead of sqlcmd because my stored procedure is creating a temporary table and performing DML statements on it? Thanks a lot

  Read the article

• Where clause in joins vs Where clause in Sub Query

  - by Kanavi

  DDL create table t ( id int Identity(1,1), nam varchar(100) ) create table t1 ( id int Identity(1,1), nam varchar(100) ) DML Insert into t( nam)values( 'a') Insert into t( nam)values( 'b') Insert into t( nam)values( 'c') Insert into t( nam)values( 'd') Insert into t( nam)values( 'e') Insert into t( nam)values( 'f') Insert into t1( nam)values( 'aa') Insert into t1( nam)values( 'bb') Insert into t1( nam)values( 'cc') Insert into t1( nam)values( 'dd') Insert into t1( nam)values( 'ee') Insert into t1( nam)values( 'ff') Query - 1 Select t.*, t1.* From t t Inner join t1 t1 on t.id = t1.id Where t.id = 1 Query 1 SQL profiler Result Reads = 56, Duration = 4 Query - 2 Select T1.*, K.* from ( Select id, nam from t Where id = 1 )K Inner Join t1 T1 on T1.id = K.id Query 2 SQL Profiler Results Reads = 262 and Duration = 2 You can also see my SQlFiddle Query - Which query should be used and why?

  Read the article

• How do I catch the exception in windows application in c#?

  - by user291169

  Where should we catch exception • In Layer Boundary (UI-BLL & BLL-DAL) • In that methods where there is no interaction between Layers only some business logic present How do I write exception in Save/Delete where some DML statement executing? • What should I write in DAL end? • What should I write in BLL end? • What should I write in UI end? In Get/Load method How do we handle exception • What should I write in BLL end? • What should I write in UI end? Should I catch System exception?

  Read the article

< Previous Page | 1 2 3 4 5  | Next Page >