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  • TakeWhile and SkipWhile method in LINQ

    - by vik20000in
     In my last post I talked about how to use the take and the Skip keyword to filter out the number of records that we are fetching. But there is only problem with the take and skip statement. The problem lies in the dependency where by the number of records to be fetched has to be passed to it. Many a times the number of records to be fetched is also based on the query itself. For example if we want to continue fetching records till a certain condition is met on the record set. Let’s say we want to fetch records from the array of number till we get 7. For this kind of query LINQ has exposed the TakeWhile Method.     int[] numbers = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 };     var firstNumbersLessThan6 = numbers.TakeWhile(n => n < 7);   In the same way we can also use the SkipWhile statement. The skip while statement will skip all the records that do not match certain condition provided. In the example below we are skiping all those number which are not divisible by 3. Remember we could have done this with where clause also, but SkipWhile method can be useful in many other situation and hence the example and the keyword.     int[] numbers = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 };     var allButFirst3Numbers = numbers.SkipWhile(n => n % 3 != 0); Vikram

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  • MySQL – Introduction to User Defined Variables

    - by Pinal Dave
    MySQL supports user defined variables to have some data that can be used later part of your query. You can save a value to a variable using a SELECT statement and later you can access its value. Unlike other RDBMSs, you do not need to declare the data type for a variable. The data type is automatically assumed when you assign a value. A value can be assigned to a variable using a SET command as shown below SET @server_type:='MySQL'; When you above command is executed, the value, MySQL is assigned to the variable called @server_type. Now you can use this variable in the later part of the code. Suppose if you want to display the value, you can use SELECT statement. SELECT @server_type; The result is MySQL. Once the value is assigned it remains for the entire session until changed by the later statements. So unlike SQL Server, you do not need to have this as part the execution code every time. (Because in SQL Server, the variables are execution scoped and dropped after the execution). You can give column name as below SELECT @server_type AS server_type; You can also SELECT statement to DECLARE and SELECT the values for a variable. SELECT @message:='Welcome to MySQL' AS MESSAGE; The result is Message -------- Welcome to MySQL You can make use of variables to effectively apply many logics. One of the useful method is to generate the row number as shown in this post MySQL – Generating Row Number for Each Row using Variable. Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: MySQL, PostADay, SQL, SQL Authority, SQL Query, SQL Tips and Tricks, T SQL

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  • SQL SERVER – Three Methods to Insert Multiple Rows into Single Table – SQL in Sixty Seconds #024 – Video

    - by pinaldave
    One of the biggest ask I have always received from developers is that if there is any way to insert multiple rows into a single table in a single statement. Currently when developers have to insert any value into the table they have to write multiple insert statements. First of all this is not only boring it is also very much time consuming as well. Additionally, one has to repeat the same syntax so many times that the word boring becomes an understatement. In the following quick video we have demonstrated three different methods to insert multiple values into a single table. -- Insert Multiple Values into SQL Server CREATE TABLE #SQLAuthority (ID INT, Value VARCHAR(100)); Method 1: Traditional Method of INSERT…VALUE -- Method 1 - Traditional Insert INSERT INTO #SQLAuthority (ID, Value) VALUES (1, 'First'); INSERT INTO #SQLAuthority (ID, Value) VALUES (2, 'Second'); INSERT INTO #SQLAuthority (ID, Value) VALUES (3, 'Third'); Clean up -- Clean up TRUNCATE TABLE #SQLAuthority; Method 2: INSERT…SELECT -- Method 2 - Select Union Insert INSERT INTO #SQLAuthority (ID, Value) SELECT 1, 'First' UNION ALL SELECT 2, 'Second' UNION ALL SELECT 3, 'Third'; Clean up -- Clean up TRUNCATE TABLE #SQLAuthority; Method 3: SQL Server 2008+ Row Construction -- Method 3 - SQL Server 2008+ Row Construction INSERT INTO #SQLAuthority (ID, Value) VALUES (1, 'First'), (2, 'Second'), (3, 'Third'); Clean up -- Clean up DROP TABLE #SQLAuthority; Related Tips in SQL in Sixty Seconds: SQL SERVER – Insert Multiple Records Using One Insert Statement – Use of UNION ALL SQL SERVER – 2008 – Insert Multiple Records Using One Insert Statement – Use of Row Constructor I encourage you to submit your ideas for SQL in Sixty Seconds. We will try to accommodate as many as we can. If we like your idea we promise to share with you educational material. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Database, Pinal Dave, PostADay, SQL, SQL Authority, SQL in Sixty Seconds, SQL Query, SQL Scripts, SQL Server, SQL Server Management Studio, SQL Tips and Tricks, T SQL, Technology, Video

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  • Materialized View does not import properly when importing a db for a second time in another schema [closed]

    - by marinus
    When I import a database with materialized view mv_mt in just one schema there are no errors. create materialized view mv_mt refresh complete next trunc( sysdate ) + 1 as SELECT sysdate, media_type.* from media_type; But when I try to import the same database to a copy in another schema in the same tablespace I get the following errors: IMP-00017: following statement failed with ORACLE error 1: "BEGIN DBMS_JOB.ISUBMIT(JOB=>438,WHAT=>'dbms_refresh.refresh(''"ALEXANDRA"" "."MV_MT"'');',NEXT_DATE=>TO_DATE('2012-07-02:14:22:36','YYYY-MM-DD:HH24:MI:" "SS'),INTERVAL=>'sysdate + 1 / 24 / 60 / 6 ',NO_PARSE=>TRUE); END;" IMP-00003: ORACLE error 1 encountered ORA-00001: unique constraint (SYS.I_JOB_JOB) violated ORA-06512: at "SYS.DBMS_JOB", line 100 ORA-06512: at line 1 IMP-00017: following statement failed with ORACLE error 23421: "BEGIN dbms_refresh.make('"ALEXANDRA"."MV_MT"',list=>null,next_date=>null," "interval=>null,implicit_destroy=>TRUE,lax=>FALSE,job=>438,rollback_seg=>NUL" "L,push_deferred_rpc=>TRUE,refresh_after_errors=>FALSE,purge_option => 1,par" "allelism => 0,heap_size => 0); END;" IMP-00003: ORACLE error 23421 encountered ORA-23421: job number 438 is not a job in the job queue ORA-06512: at "SYS.DBMS_SYS_ERROR", line 86 ORA-06512: at "SYS.DBMS_IJOB", line 793 ORA-06512: at "SYS.DBMS_REFRESH", line 86 ORA-06512: at "SYS.DBMS_REFRESH", line 62 ORA-06512: at line 1 IMP-00017: following statement failed with ORACLE error 23410: "BEGIN dbms_refresh.add(name=>'"ALEXANDRA"."MV_MT"',list=>'"ALEXANDRA"."MV" "_MT"',siteid=>0,export_db=>'ORCL01'); END;" IMP-00003: ORACLE error 23410 encountered ORA-23410: materialized view "ALEXANDRA"."MV_MT" is already in a refresh group ORA-06512: at "SYS.DBMS_SYS_ERROR", line 95 ORA-06512: at "SYS.DBMS_IREFRESH", line 484 ORA-06512: at "SYS.DBMS_REFRESH", line 140 ORA-06512: at "SYS.DBMS_REFRESH", line 125 ORA-06512: at line 1 Anyone any ideas?

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  • How do I Delete a View? How do I Create a View?

    - by Paula DiTallo
    Before I create views, I generally work out what I want to retrieve in my SELECT statement ahead of time so I'll just  have to cut and  paste the query. The example below is done  in T-SQL/Sybase format, however for Oracle and MySQL, just  place a semi-colon ';' at the end of your statement and remove the  'GO' command.          To drop (delete) an existing view: DROP VIEW vw_rpt_metroBestCustomers GO To create a view: CREATE VIEW vw_rpt_metroBestCustomers ( CustomerName,    OfficeNum,    City,    StateOrProv,    Country,    ZipCode   ) AS SELECT a.FirstName + ', ' + a.LastName,           b.OfficePhoneNum,           c.City,           c.StateOrProvAbbr,           c.Country,           c.PostalCode     FROM Customer a,          CustLocAssoc x,          CustContactAssoc y,          Location c,          Contact b     WHERE a.CustID = x.CustID       AND a.CustID = y.CustID       AND y.ContactID = b.ContactID       AND x.LocID = c.LocID       AND a.LoyaltyMedian > 85.5 GO        I frequently rename columns when developing views to makeit easier for simple, text-based reporting--however, renamingthe columns isn't necessary.The create view statement above could have been writtenas follows:CREATE VIEW vw_rpt_metroBestCustomersAS (SELECT a.FirstName + ', ' + a.LastName, b.OfficePhoneNum, c.City, c.StateOrProvAbbr, c.Country, c.PostalCode FROM Customer a, CustLocAssoc x, CustContactAssoc y, Location c, Contact b WHERE a.CustID = x.CustID AND a.CustID = y.CustID AND y.ContactID = b.ContactID AND x.LocID = c.LocID AND a.LoyaltyMedian > 85.5 )GO

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  • SQL Server Interview Questions

    - by Rodney Vinyard
    User-Defined Functions Scalar User-Defined Function A Scalar user-defined function returns one of the scalar data types. Text, ntext, image and timestamp data types are not supported. These are the type of user-defined functions that most developers are used to in other programming languages. Table-Value User-Defined Function An Inline Table-Value user-defined function returns a table data type and is an exceptional alternative to a view as the user-defined function can pass parameters into a T-SQL select command and in essence provide us with a parameterized, non-updateable view of the underlying tables. Multi-statement Table-Value User-Defined Function A Multi-Statement Table-Value user-defined function returns a table and is also an exceptional alternative to a view as the function can support multiple T-SQL statements to build the final result where the view is limited to a single SELECT statement. Also, the ability to pass parameters into a T-SQL select command or a group of them gives us the capability to in essence create a parameterized, non-updateable view of the data in the underlying tables. Within the create function command you must define the table structure that is being returned. After creating this type of user-defined function, I can use it in the FROM clause of a T-SQL command unlike the behavior found when using a stored procedure which can also return record sets.

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  • Cross Apply Ambiguity

    - by Dave Ballantyne
    Cross apply (and outer apply)  are a very welcome addition to the TSQL language.  However, today after a few hours of head scratching, I have found an simple issue which could cause big big problems. What would you expect from this statement ? select * from sys.objects b join sys.objects a on a.object_id = object_id No prizes for guessing SQL server errors with “Ambiguous column name 'object_id'”. What would you expect from this statement ? Select * from sys.objects a cross apply( Select * from sys.objects b where b.object_id = object_id) as c Surprisingly, perhaps, the result is a cross join of sys.objects.  Well, what happened there ? If you look at the apply statement, within the where clause, only one of the conditions is qualified with a table name.  This meant that is has be interpreted as “b.object_id = b.object_id” causing the cross apply to have no join the the parent sys.objects table and causing the cross join. The fix is , obviously, simple Select * from sys.objects a cross apply( Select * from sys.objects b where b.object_id = a.object_id) as c So why no “Ambiguous column name ” error ?  I’ve raised a connect item on this issue here.

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  • A Look Inside JSR 360 - CLDC 8

    - by Roger Brinkley
    If you didn't notice during JavaOne the Java Micro Edition took a major step forward in its consolidation with Java Standard Edition when JSR 360 was proposed to the JCP community. Over the last couple of years there has been a focus to move Java ME back in line with it's big brother Java SE. We see evidence of this in JCP itself which just recently merged the ME and SE/EE Executive Committees into a single Java Executive Committee. But just before that occurred JSR 360 was proposed and approved for development on October 29. So let's take a look at what changes are now being proposed. In a way JSR 360 is returning back to the original roots of Java ME when it was first introduced. It was indeed a subset of the JDK 4 language, but as Java progressed many of the language changes were not implemented in the Java ME. Back then the tradeoff was still a functionality, footprint trade off but the major market was feature phones. Today the market has changed and CLDC, while it will still target feature phones, will have it primary emphasis on embedded devices like wireless modules, smart meters, health care monitoring and other M2M devices. The major changes will come in three areas: language feature changes, library changes, and consolidating the Generic Connection Framework.  There have been three Java SE versions that have been implemented since JavaME was first developed so the language feature changes can be divided into changes that came in JDK 5 and those in JDK 7, which mostly consist of the project Coin changes. There were no language changes in JDK 6 but the changes from JDK 5 are: Assertions - Assertions enable you to test your assumptions about your program. For example, if you write a method that calculates the speed of a particle, you might assert that the calculated speed is less than the speed of light. In the example code below if the interval isn't between 0 and and 1,00 the an error of "Invalid value?" would be thrown. private void setInterval(int interval) { assert interval > 0 && interval <= 1000 : "Invalid value?" } Generics - Generics add stability to your code by making more of your bugs detectable at compile time. Code that uses generics has many benefits over non-generic code with: Stronger type checks at compile time. Elimination of casts. Enabling programming to implement generic algorithms. Enhanced for Loop - the enhanced for loop allows you to iterate through a collection without having to create an Iterator or without having to calculate beginning and end conditions for a counter variable. The enhanced for loop is the easiest of the new features to immediately incorporate in your code. In this tip you will see how the enhanced for loop replaces more traditional ways of sequentially accessing elements in a collection. void processList(Vector<string> list) { for (String item : list) { ... Autoboxing/Unboxing - This facility eliminates the drudgery of manual conversion between primitive types, such as int and wrapper types, such as Integer.  Hashtable<Integer, string=""> data = new Hashtable<>(); void add(int id, String value) { data.put(id, value); } Enumeration - Prior to JDK 5 enumerations were not typesafe, had no namespace, were brittle because they were compile time constants, and provided no informative print values. JDK 5 added support for enumerated types as a full-fledged class (dubbed an enum type). In addition to solving all the problems mentioned above, it allows you to add arbitrary methods and fields to an enum type, to implement arbitrary interfaces, and more. Enum types provide high-quality implementations of all the Object methods. They are Comparable and Serializable, and the serial form is designed to withstand arbitrary changes in the enum type. enum Season {WINTER, SPRING, SUMMER, FALL}; } private Season season; void setSeason(Season newSeason) { season = newSeason; } Varargs - Varargs eliminates the need for manually boxing up argument lists into an array when invoking methods that accept variable-length argument lists. The three periods after the final parameter's type indicate that the final argument may be passed as an array or as a sequence of arguments. Varargs can be used only in the final argument position. void warning(String format, String... parameters) { .. for(String p : parameters) { ...process(p);... } ... } Static Imports -The static import construct allows unqualified access to static members without inheriting from the type containing the static members. Instead, the program imports the members either individually or en masse. Once the static members have been imported, they may be used without qualification. The static import declaration is analogous to the normal import declaration. Where the normal import declaration imports classes from packages, allowing them to be used without package qualification, the static import declaration imports static members from classes, allowing them to be used without class qualification. import static data.Constants.RATIO; ... double r = Math.cos(RATIO * theta); Annotations - Annotations provide data about a program that is not part of the program itself. They have no direct effect on the operation of the code they annotate. There are a number of uses for annotations including information for the compiler, compiler-time and deployment-time processing, and run-time processing. They can be applied to a program's declarations of classes, fields, methods, and other program elements. @Deprecated public void clear(); The language changes from JDK 7 are little more familiar as they are mostly the changes from Project Coin: String in switch - Hey it only took us 18 years but the String class can be used in the expression of a switch statement. Fortunately for us it won't take that long for JavaME to adopt it. switch (arg) { case "-data": ... case "-out": ... Binary integral literals and underscores in numeric literals - Largely for readability, the integral types (byte, short, int, and long) can also be expressed using the binary number system. and any number of underscore characters (_) can appear anywhere between digits in a numerical literal. byte flags = 0b01001111; long mask = 0xfff0_ff08_4fff_0fffl; Multi-catch and more precise rethrow - A single catch block can handle more than one type of exception. In addition, the compiler performs more precise analysis of rethrown exceptions than earlier releases of Java SE. This enables you to specify more specific exception types in the throws clause of a method declaration. catch (IOException | InterruptedException ex) { logger.log(ex); throw ex; } Type Inference for Generic Instance Creation - Otherwise known as the diamond operator, the type arguments required to invoke the constructor of a generic class can be replaced with an empty set of type parameters (<>) as long as the compiler can infer the type arguments from the context.  map = new Hashtable<>(); Try-with-resource statement - The try-with-resources statement is a try statement that declares one or more resources. A resource is an object that must be closed after the program is finished with it. The try-with-resources statement ensures that each resource is closed at the end of the statement.  try (DataInputStream is = new DataInputStream(...)) { return is.readDouble(); } Simplified varargs method invocation - The Java compiler generates a warning at the declaration site of a varargs method or constructor with a non-reifiable varargs formal parameter. Java SE 7 introduced a compiler option -Xlint:varargs and the annotations @SafeVarargs and @SuppressWarnings({"unchecked", "varargs"}) to supress these warnings. On the library side there are new features that will be added to satisfy the language requirements above and some to improve the currently available set of APIs.  The library changes include: Collections update - New Collection, List, Set and Map, Iterable and Iteratator as well as implementations including Hashtable and Vector. Most of the work is too support generics String - New StringBuilder and CharSequence as well as a Stirng formatter. The javac compiler  now uses the the StringBuilder instead of String Buffer. Since StringBuilder is synchronized there is a performance increase which has necessitated the wahat String constructor works. Comparable interface - The comparable interface works with Collections, making it easier to reuse. Try with resources - Closeable and AutoCloseable Annotations - While support for Annotations is provided it will only be a compile time support. SuppressWarnings, Deprecated, Override NIO - There is a subset of NIO Buffer that have been in use on the of the graphics packages and needs to be pulled in and also support for NIO File IO subset. Platform extensibility via Service Providers (ServiceLoader) - ServiceLoader interface dos late bindings of interface to existing implementations. It helpe to package an interface and behavior of the implementation at a later point in time.Provider classes must have a zero-argument constructor so that they can be instantiated during loading. They are located and instantiated on demand and are identified via a provider-configuration file in the METAINF/services resource directory. This is a mechansim from Java SE. import com.XYZ.ServiceA; ServiceLoader<ServiceA> sl1= new ServiceLoader(ServiceA.class); Resources: META-INF/services/com.XYZ.ServiceA: ServiceAProvider1 ServiceAProvider2 ServiceAProvider3 META-INF/services/ServiceB: ServiceBProvider1 ServiceBProvider2 From JSR - I would rather use this list I think The Generic Connection Framework (GCF) was previously specified in a number of different JSRs including CLDC, MIDP, CDC 1.2, and JSR 197. JSR 360 represents a rare opportunity to consolidated and reintegrate parts that were duplicated in other specifications into a single specification, upgrade the APIs as well provide new functionality. The proposal is to specify a combined GCF specification that can be used with Java ME or Java SE and be backwards compatible with previous implementations. Because of size limitations as well as the complexity of the some features like InvokeDynamic and Unicode 6 will not be included. Additionally, any language or library changes in JDK 8 will be not be included. On the upside, with all the changes being made, backwards compatibility will still be maintained. JSR 360 is a major step forward for Java ME in terms of platform modernization, language alignment, and embedded support. If you're interested in following the progress of this JSR see the JSR's java.net project for details of the email lists, discussions groups.

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  • Materialized View does not import properly when importing on a second instance of a database

    - by marinus
    When I import a database with materialized view mv_mt in just one database (Oracle) everything is ok. create materialized view mv_mt refresh complete next trunc( sysdate ) + 1 as SELECT sysdate, media_type.* from media_type; But when I try to import the same database to a copy in another schema I get the following errors: IMP-00017: following statement failed with ORACLE error 1: "BEGIN DBMS_JOB.ISUBMIT(JOB=438,WHAT='dbms_refresh.refresh(''"ALEXANDRA"" "."MV_MT"'');',NEXT_DATE=TO_DATE('2012-07-02:14:22:36','YYYY-MM-DD:HH24:MI:" "SS'),INTERVAL='sysdate + 1 / 24 / 60 / 6 ',NO_PARSE=TRUE); END;" IMP-00003: ORACLE error 1 encountered ORA-00001: unique constraint (SYS.I_JOB_JOB) violated ORA-06512: at "SYS.DBMS_JOB", line 100 ORA-06512: at line 1 IMP-00017: following statement failed with ORACLE error 23421: "BEGIN dbms_refresh.make('"ALEXANDRA"."MV_MT"',list=null,next_date=null," "interval=null,implicit_destroy=TRUE,lax=FALSE,job=438,rollback_seg=NUL" "L,push_deferred_rpc=TRUE,refresh_after_errors=FALSE,purge_option = 1,par" "allelism = 0,heap_size = 0); END;" IMP-00003: ORACLE error 23421 encountered ORA-23421: job number 438 is not a job in the job queue ORA-06512: at "SYS.DBMS_SYS_ERROR", line 86 ORA-06512: at "SYS.DBMS_IJOB", line 793 ORA-06512: at "SYS.DBMS_REFRESH", line 86 ORA-06512: at "SYS.DBMS_REFRESH", line 62 ORA-06512: at line 1 IMP-00017: following statement failed with ORACLE error 23410: "BEGIN dbms_refresh.add(name='"ALEXANDRA"."MV_MT"',list='"ALEXANDRA"."MV" "_MT"',siteid=0,export_db='ORCL01'); END;" IMP-00003: ORACLE error 23410 encountered ORA-23410: materialized view "ALEXANDRA"."MV_MT" is already in a refresh group ORA-06512: at "SYS.DBMS_SYS_ERROR", line 95 ORA-06512: at "SYS.DBMS_IREFRESH", line 484 ORA-06512: at "SYS.DBMS_REFRESH", line 140 ORA-06512: at "SYS.DBMS_REFRESH", line 125 ORA-06512: at line 1 Anyone any ideas? Regards, Marinus

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  • TraceTune: Larger Files and History

    - by Bill Graziano
    I updated TraceTune over the weekend.  I increased the trace file upload size to 20MB.  We’ve processed over half a million rows of trace data so far and I’m confident this won’t kill the server. I added average CPU and average disk reads to the screen that lists the SQL statements in a trace file. I only added these two.  I’m pretty sure average writes isn’t that import.  I’m still thinking about average duration.  I’m trying to balance showing you what you need with a clean, simple interface.  Plus I have a way to see the averages that I describe further down. TraceTune now keeps the last 10 files that you’ve uploaded and will give you some basic details about each file. I think the last change I made is the most interesting. For each SQL statement, I show the history of that statement. You’ll see each trace file where this statement was found.  It will list the averages for CPU, reads, writes and duration.  This will quickly show you if you’re improving the performance of that query.  In my screen shot above you can that even though the execution counts are very different the averages are consistent. If you want to see what queries are consuming the most resources on your server give TraceTune a try.

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  • Dreaded SQLs

    - by lavanyadeepak
    Dreaded SQLs We used to think that a SQL statement without a where clause is only dangerous right since running that on a server TSQL is just going to impact the entire table like waving the magic wand. For that reason we should cultivate the habit first to write the statement as select and then to modify the select portion as update. Within the T-SQL Window, I would normally prefer the following first: select * from employee where empid in (4,5) and then once I am satisfied with the results, I would go ahead with the following change: --select * delete from employee where empid in (4,5) Today I just discovered another coding horror. This would typically be applicable in a stored procedure and with respect to variable nomenclature. It is always desirable to have a suitable nomenclature for parameters distinct from the column names and internal variables. This would help quicker debugging of the stored procedures besides enhancing the readability. Else in a quick bout of enthusiasm a statement like   if (@CustomerID = @CustomerID) [when the latter is intended to denote the column name and there is a superflous @ prepended], zeroing in on the problem would be little tricky. Had there been a still powerful nomenclature rules then debugging would have been more straight-forward and simpler right?

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  • mysql query using jdbc

    - by S.PRATHIBA
    Hi all, I need to retrieve the last 20 values from my database.For example I have the following table Service_ID Service_Type consumer_feedback | 36 | Printer | 0 | | 36 | Printer | 1 | | 36 | Printer | 0 | | 36 | Printer | 1 | | 36 | Printer | 0 | | 36 | Printer | 1 | | 36 | Printer | 0 | | 36 | Printer | 1 | | 36 | Printer | 0 | | 36 | Printer | 1 | | 36 | Printer | 0 | | 36 | Printer | 1 | | 36 | Printer | 0 | | 36 | Printer | 1 | | 36 | Printer | 0 | | 36 | Printer | 1 | | 36 | Printer | 0 | | 36 | Printer | 1 | | 36 | Printer | 0 | | 36 | Printer | 1 | | 36 | Printer | 0 | | 36 | Printer | 1 | | 36 | Printer | 0 | | 36 | Printer | 1 | | 36 | Printer | 0 | | 36 | Printer | 1 | | 36 | Printer | 0 | | 36 | Printer | 1 | | 36 | Printer | 0 | | 36 | Printer | 1 | | 36 | Printer | 0 | | 36 | Printer | 1 | | 36 | Printer | 0 | | 36 | Printer | 1 | | 36 | Printer | 0 | | 36 | Printer | 1 | | 36 | Printer | 0 | | 36 | Printer | 1 | | 36 | Printer | 0 | | 36 | Printer | 1 | | 36 | Printer | 0 | | 36 | Printer | 1 | | 36 | Printer | 0 | | 36 | Printer | 1 | | 36 | Printer | 0 | | 36 | Printer | 1 | | 36 | Printer | 0 | | 36 | Printer | 1 | | 36 | Printer | 0 | | 36 | Printer | 1 | | 36 | Printer | 0 | | 36 | Printer | 1 | | 36 | Printer | 0 | | 36 | Printer | 1 | | 36 | Printer | 0 | | 36 | Printer | 1 | | 36 | Printer | 0 | | 36 | Printer | 1 | | 36 | Printer | 0 | | 36 | Printer | 1 | | 36 | Printer | 0 | | 36 | Printer | 1 | | 36 | Printer | 0 | | 37 | Printer | 0 | | 39 | Printer | -1 | | 39 | Printer | 0 | | 40 | Printer | 0 | I need to retrieve last 10 values from the table.I need to do the operation using jdbc.I have attached the sample code.Kindly help me. import java.io.; import java.sql.; public class CountRows2 { public static void main(String[] args) { System.out.println("Count number of rows in a specific table!"); Connection con = null; int count = 0; try{ Class.forName("com.mysql.jdbc.Driver"); con = DriverManager.getConnection ("jdbc:mysql://localhost:3306/prathi","root","mysql"); try{ Statement st = con.createStatement(); ResultSet res1 = st.executeQuery("SELECT COUNT(*) FROM consumer1" ); while (res1.next()){ count = res1.getInt(1); } System.out.println("Number of column:"+count); } catch (SQLException s){ System.out.println("SQL statement is not executed!"); } } catch (Exception e){ e.printStackTrace(); } try{ Class.forName("com.mysql.jdbc.Driver"); con = DriverManager.getConnection ("jdbc:mysql://localhost:3306/prathi","root","mysql"); try{ Statement st = con.createStatement(); ResultSet res1 = st.executeQuery("SELECT * FROM consumer1 LIMIT count-10,10"); while (res1.next()){ int Service = res1.getInt(1); String s1 = res1.getString(2); int feedback=res1.getInt(3); } System.out.println("Service" + " " +"s1" + " " +"feedback"); } catch (SQLException s){ System.out.println("SQL statement is not executed!"); } } catch (Exception e){ e.printStackTrace(); } } } I am getting the output as: C:javac CountRows2.java C:java CountRows2 Count number of rows in a specific table! Number of column:558 SQL statement is not executed! Thanks a lot....

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  • GOTO still considered harmful?

    - by Kyle Cronin
    Everyone is aware of Dijkstra's Letters to the editor: go to statement considered harmful (also here .html transcript and here .pdf) and there has been a formidable push since that time to eschew the goto statement whenever possible. While it's possible to use goto to produce unmaintainable, sprawling code, it nevertheless remains in modern programming languages. Even the advanced continuation control structure in Scheme can be described as a sophisticated goto. What circumstances warrant the use of goto? When is it best to avoid? As a followup question: C provides a pair of functions, setjmp and longjmp, that provide the ability to goto not just within the current stack frame but within any of the calling frames. Should these be considered as dangerous as goto? More dangerous? Dijkstra himself regretted that title, of which he was not responsible for. At the end of EWD1308 (also here .pdf) he wrote: Finally a short story for the record. In 1968, the Communications of the ACM published a text of mine under the title "The goto statement considered harmful", which in later years would be most frequently referenced, regrettably, however, often by authors who had seen no more of it than its title, which became a cornerstone of my fame by becoming a template: we would see all sorts of articles under the title "X considered harmful" for almost any X, including one titled "Dijkstra considered harmful". But what had happened? I had submitted a paper under the title "A case against the goto statement", which, in order to speed up its publication, the editor had changed into a "letter to the Editor", and in the process he had given it a new title of his own invention! The editor was Niklaus Wirth. A well thought out classic paper about this topic, to be matched to that of Dijkstra, is Structured Programming with go to Statements (also here .pdf), by Donald E. Knuth. Reading both helps to reestablish context and a non-dogmatic understanding of the subject. In this paper, Dijkstra's opinion on this case is reported and is even more strong: Donald E. Knuth: I believe that by presenting such a view I am not in fact disagreeing sharply with Dijkstra's ideas, since he recently wrote the following: "Please don't fall into the trap of believing that I am terribly dogmatical about [the go to statement]. I have the uncomfortable feeling that others are making a religion out of it, as if the conceptual problems of programming could be solved by a single trick, by a simple form of coding discipline!"

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  • MS Access 2003 - Option Group frame: can I add text boxes that are part of the frame instead of rad

    - by Justin
    Ok so this maybe a simple/silly question but I don't know so here goes: In access let's say I want to have a frame control, so I click the option group button and add it to the desgin surface. However, I am not wanting to use this as a option group with radio button selection, instead I would like to add text boxes instead the frame, so that when I reference the frame, it references every control instead of it, hence the text boxes, cbo boxes, etc.....just as it would if they were radio option selections. So can you do this? I want whatever controls I add inside the frame to be easily referenced (i.e. make all controls visible just by using frameExample.visible = true) so that I can build my own tab control groupings..... can this be done? Thanks! EDIT: What I am trying to accomplish is having a form that includes a collection of controls (input controls - cbo boxes, text boxes, etc), that serve as the Main record information. These are saved to a table via an INSERT statement on button_click because this form is unbound. Next I have 8 categories that are relative per each main record (and data that goes along with it). Each of these categories could have a sub form area and a button click that bring it's relative form into the sub form area. These sub forms would be unbound as well as I would just save data via SQL statement. So i know I could accomplish this by running the insert statement from the parent form, on the main collection control's data that would create the KeyID number, then run a SQL statement that would turn around and load that KeyID number right back onto the page in a hidden text box. Then when I click one of the sub forms and load its relative collection of controls, I could then save that data along with KeyID for each of these sub-forms/tables. SO...... I was wondering if instead you could define these controls as a collection so that you could hide and make visible all the ones you need on button clicks and avoid the need for additional forms (subs). I know that if a user enters data into a text box, and then somewhere along the way that box becomes hidden, the data still exists in it and still ends up in the SQL statement.... So I want all these controls to exist on the same form, but I thought what is I could encapsulate them into a frame like an option group, then I could call the frame and all the relative controls would be called up (made visible) as needed. Sorry for the long explanation but I thought it would help.

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  • A lock could not obtained within the time requested issue

    - by Wayne Daly
    The title is the error I'm getting, when I click load my program freezes. I assume its because I'm doing a statement inside a statement, but from what I see its the only solution to my issue. By loading I want to just repopulate the list of patients, but to do so I need to do their conditions also. The code works, the bottom method is what I'm trying to fix. I think the issue is that I have 2 statements open but I am not sure. load: public void DatabaseLoad() { try { String Name = "Wayne"; String Pass= "Wayne"; String Host = "jdbc:derby://localhost:1527/Patients"; Connection con = DriverManager.getConnection( Host,Name, Pass); PatientList.clear(); Statement stmt8 = con.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_UPDATABLE); String SQL8 = "SELECT * FROM PATIENTS"; ResultSet rs8 = stmt8.executeQuery( SQL8 ); ArrayList<PatientCondition> PatientConditions1 = new ArrayList(); while(rs8.next()) { PatientConditions1 = LoadPatientConditions(); } Statement stmt = con.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_UPDATABLE); String SQL = "SELECT * FROM PATIENTS"; ResultSet rs = stmt.executeQuery( SQL ); while(rs.next()) { int id = (rs.getInt("ID")); String name = (rs.getString("NAME")); int age = (rs.getInt("AGE")); String address = (rs.getString("ADDRESS")); String sex = (rs.getString("SEX")); String phone = (rs.getString("PHONE")); Patient p = new Patient(id, name, age, address, sex, phone, PatientConditions1); PatientList.add(p); } UpdateTable(); UpdateAllViews(); DefaultListModel PatientListModel = new DefaultListModel(); for (Patient s : PatientList) { PatientListModel.addElement(s.getAccountNumber() + "-" + s.getName()); } PatientJList.setModel(PatientListModel); } catch(SQLException err) { System.out.println(err.getMessage()); } } This is the method that returns the arraylist of patient conditions public ArrayList LoadPatientConditions() { ArrayList<PatientCondition> PatientConditionsTemp = new ArrayList(); try { String Name = "Wayne"; String Pass= "Wayne"; String Host = "jdbc:derby://localhost:1527/Patients"; Connection con = DriverManager.getConnection( Host,Name, Pass); Statement stmt = con.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_UPDATABLE); String SQL = "SELECT * FROM PATIENTCONDITIONS"; ResultSet rs5 = stmt.executeQuery( SQL ); int e = 0; while(rs5.next()) { e++; String ConName = (rs5.getString("CONDITION")); PatientCondition k = new PatientCondition(e,ConName); PatientConditionsTemp.add(k); } } catch(SQLException err) { System.out.println(err.getMessage()); } return PatientConditionsTemp; }

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  • SQL SERVER – DMV – sys.dm_os_wait_stats Explanation – Wait Type – Day 3 of 28

    - by pinaldave
    The key Dynamic Management View (DMV) that helps us to understand wait stats is sys.dm_os_wait_stats; this DMV gives us all the information that we need to know regarding wait stats. However, the interpretation is left to us. This is a challenge as understanding wait stats can often be quite tricky. Anyway, we will cover few wait stats in one of the future articles. Today we will go over the basic understanding of the DMV. The Official Book OnLine Reference for DMV is over here: sys.dm_os_wait_stats. I suggest you all to refer this for all the accuracy. Following is a statement from the online book: “Specific types of wait times during query execution can indicate bottlenecks or stall points within the query. Similarly, high wait times, or wait counts server wide can indicate bottlenecks or hot spots in interaction query interactions within the server instance.” This is the statement which has inspired me to write this series. Let us first run the following statement from DMV. SELECT * FROM sys.dm_os_wait_stats ORDER BY wait_time_ms DESC GO Above statement will show us few of the columns. Here it is quick explanation of each of the column. wait_type – this is the name of the wait type. There can be three different kinds of wait types – resource, queue and external. waiting_tasks_count – this incremental counter is a good indication of frequent the wait is happening. If this number is very high, it is good indication for us to investigate that particular wait type. It is quite possible that the wait time is considerably low, but the frequency of the wait is much high. wait_time_ms – this is total wait accumulated for any type of wait. This is the total wait time and includes singal_wait_time_ms. max_wait_time_ms – this indicates the maximum wait type ever occurred for that particular wait type. Using this, one can estimate the intensity of the wait type in past. Again, it is not necessary that this max wait time will occur every time; so do not over invest yourself here. signal_wait_time_ms – this is the wait time when thread is marked as runnable and it gets to the running state. If the runnable queue is very long, you will find that this wait time becomes high. Additionally, please note that this DMV does not show current wait type or wait stats. This is cumulative view of the all the wait stats since server (instance) restarted or wait stats have been cleared. In future blog post, we will also cover two more DMVs which can be helpful to identify wait-related issues. ?sys.dm_os_waiting_tasks sys.dm_exec_requests Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL DMV, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQL Wait Stats, SQL Wait Types, T SQL, Technology

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  • Does my use of the strategy pattern violate the fundamental MVC pattern in iOS?

    - by Goodsquirrel
    I'm about to use the 'strategy' pattern in my iOS app, but feel like my approach violates the somehow fundamental MVC pattern. My app is displaying visual "stories", and a Story consists (i.e. has @properties) of one Photo and one or more VisualEvent objects to represent e.g. animated circles or moving arrows on the photo. Each VisualEvent object therefore has a eventType @property, that might be e.g. kEventTypeCircle or kEventTypeArrow. All events have things in common, like a startTime @property, but differ in the way they are being drawn on the StoryPlayerView. Currently I'm trying to follow the MVC pattern and have a StoryPlayer object (my controller) that knows about both the model objects (like Story and all kinds of visual events) and the view object StoryPlayerView. To chose the right drawing code for each of the different visual event types, my StoryPlayer is using a switch statement. @implementation StoryPlayer // (...) - (void)showVisualEvent:(VisualEvent *)event onStoryPlayerView:storyPlayerView { switch (event.eventType) { case kEventTypeCircle: [self showCircleEvent:event onStoryPlayerView:storyPlayerView]; break; case kEventTypeArrow: [self showArrowDrawingEvent:event onStoryPlayerView:storyPlayerView]; break; // (...) } But switch statements for type checking are bad design, aren't they? According to Uncle Bob they lead to tight coupling and can and should almost always be replaced by polymorphism. Having read about the "Strategy"-Pattern in Head First Design Patterns, I felt this was a great way to get rid of my switch statement. So I changed the design like this: All specialized visual event types are now subclasses of an abstract VisualEvent class that has a showOnStoryPlayerView: method. @interface VisualEvent : NSObject - (void)showOnStoryPlayerView:(StoryPlayerView *)storyPlayerView; // abstract Each and every concrete subclass implements a concrete specialized version of this drawing behavior method. @implementation CircleVisualEvent - (void)showOnStoryPlayerView:(StoryPlayerView *)storyPlayerView { [storyPlayerView drawCircleAtPoint:self.position color:self.color lineWidth:self.lineWidth radius:self.radius]; } The StoryPlayer now simply calls the same method on all types of events. @implementation StoryPlayer - (void)showVisualEvent:(VisualEvent *)event onStoryPlayerView:storyPlayerView { [event showOnStoryPlayerView:storyPlayerView]; } The result seems to be great: I got rid of the switch statement, and if I ever have to add new types of VisualEvents in the future, I simply create new subclasses of VisualEvent. And I won't have to change anything in StoryPlayer. But of cause this approach violates the MVC pattern since now my model has to know about and depend on my view! Now my controller talks to my model and my model talks to the view calling methods on StoryPlayerView like drawCircleAtPoint:color:lineWidth:radius:. But this kind of calls should be controller code not model code, right?? Seems to me like I made things worse. I'm confused! Am I completely missing the point of the strategy pattern? Is there a better way to get rid of the switch statement without breaking model-view separation?

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  • Database Mirroring on SQL Server Express Edition

    - by Most Valuable Yak (Rob Volk)
    Like most SQL Server users I'm rather frustrated by Microsoft's insistence on making the really cool features only available in Enterprise Edition.  And it really doesn't help that they changed the licensing for SQL 2012 to be core-based, so now it's like 4 times as expensive!  It almost makes you want to go with Oracle.  That, and a desire to have Larry Ellison do things to your orifices. And since they've introduced Availability Groups, and marked database mirroring as deprecated, you'd think they'd make make mirroring available in all editions.  Alas…they don't…officially anyway.  Thanks to my constant poking around in places I'm not "supposed" to, I've discovered the low-level code that implements database mirroring, and found that it's available in all editions! It turns out that the query processor in all SQL Server editions prepends a simple check before every edition-specific DDL statement: IF CAST(SERVERPROPERTY('Edition') as nvarchar(max)) NOT LIKE '%e%e%e% Edition%' print 'Lame' else print 'Cool' If that statement returns true, it fails. (the print statements are just placeholders)  Go ahead and test it on Standard, Workgroup, and Express editions compared to an Enterprise or Developer edition instance (which support everything). Once again thanks to Argenis Fernandez (b | t) and his awesome sessions on using Sysinternals, I was able to watch the exact process SQL Server performs when setting up a mirror.  Surprisingly, it's not actually implemented in SQL Server!  Some of it is, but that's something of a smokescreen, the real meat of it is simple filesystem primitives. The NTFS filesystem supports links, both hard links and symbolic, so that you can create two entries for the same file in different directories and/or different names.  You can create them using the MKLINK command in a command prompt: mklink /D D:\SkyDrive\Data D:\Data mklink /D D:\SkyDrive\Log D:\Log This creates a symbolic link from my data and log folders to my Skydrive folder.  Any file saved in either location will instantly appear in the other.  And since my Skydrive will be automatically synchronized with the cloud, any changes I make will be copied instantly (depending on my internet bandwidth of course). So what does this have to do with database mirroring?  Well, it seems that the mirroring endpoint that you have to create between mirror and principal servers is really nothing more than a Skydrive link.  Although it doesn't actually use Skydrive, it performs the same function.  So in effect, the following statement: ALTER DATABASE Mir SET PARTNER='TCP://MyOtherServer.domain.com:5022' Is turned into: mklink /D "D:\Data" "\\MyOtherServer.domain.com\5022$" The 5022$ "port" is actually a hidden system directory on the principal and mirror servers. I haven't quite figured out how the log files are included in this, or why you have to SET PARTNER on both principal and mirror servers, except maybe that mklink has to do something special when linking across servers.  I couldn't get the above statement to work correctly, but found that doing mklink to a local Skydrive folder gave me similar functionality. To wrap this up, all you have to do is the following: Install Skydrive on both SQL Servers (principal and mirror) and set the local Skydrive folder (D:\SkyDrive in these examples) On the principal server, run mklink /D on the data and log folders to point to SkyDrive: mklink /D D:\SkyDrive\Data D:\Data On the mirror server, run the complementary linking: mklink /D D:\Data D:\SkyDrive\Data Create your database and make sure the files map to the principal data and log folders (D:\Data and D:\Log) Viola! Your databases are kept in sync on multiple servers! One wrinkle you will encounter is that the mirror server will show the data and log files, but you won't be able to attach them to the mirror SQL instance while they are attached to the principal. I think this is a bug in the Skydrive, but as it turns out that's fine: you can't access a mirror while it's hosted on the principal either.  So you don't quite get automatic failover, but you can attach the files to the mirror if the principal goes offline.  It's also not exactly synchronous, but it's better than nothing, and easier than either replication or log shipping with a lot less latency. I will end this with the obvious "not supported by Microsoft" and "Don't do this in production without an updated resume" spiel that you should by now assume with every one of my blog posts, especially considering the date.

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  • one more question on sqlite3 for iphone..sorry*

    - by summer
    let's say i am trying to save an image selected from photo library to database..is the following code correct? Snap.m - (void) addSnap { if(addStmt == nil) { const char *sql = "insert into Snap(snapTitle, snapDesc, snapImage) Values(?, ?, ?)"; if(sqlite3_prepare_v2(database, sql, -1, &addStmt, NULL) != SQLITE_OK) NSAssert1(0, @"Error while creating add statement. '%s'", sqlite3_errmsg(database)); } sqlite3_bind_text(addStmt, 1, [snapTitle UTF8String], -1, SQLITE_TRANSIENT);//bind titleSnap to insert statement sqlite3_bind_text(addStmt, 2, [snapDescription UTF8String], -2, SQLITE_TRANSIENT); sqlite3_bind_int(addStmt, 3, snapID); NSData *imgData = UIImagePNGRepresentation(self.snapImage); int returnValue = -1; if(self.snapImage != nil) returnValue = sqlite3_bind_blob(addStmt, 3, [imgData bytes], [imgData length], SQLITE_TRANSIENT); else returnValue = sqlite3_bind_blob(addStmt, 3, nil, -1, NULL); sqlite3_bind_int(addStmt, 4, snapID); if(returnValue != SQLITE_OK) NSLog(@"Not OK!!!"); if(SQLITE_DONE != sqlite3_step(addStmt))//execute step statement if it return SQLITE_DONE NSAssert1(0, @"Error while inserting data. '%s'", sqlite3_errmsg(database)); else //sqlite3_last_insert_rowid snapID = sqlite3_last_insert_rowid(database);//get primary key for the row which was inserted //reset add statement sqlite3_reset(addStmt); } - (void)setSnapImage:(UIImageView *)theSnapImage { self.isDirty = YES; [snapImage release]; snapImage = [theSnapImage copy]; } then to get the "object" i use.. snap2playObj.snapImage = imageView.image; i am using UIImageView by the way..my error message.. -[UIImage copyWithZone:]: unrecognized selector sent to instance 0xd74750 2010-03-18 16:22:27.808 Snap2Play[68317:20b] * Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '* -[UIImage copyWithZone:]: unrecognized selector sent to instance 0xd74750'

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  • Parsing some particular statements with antlr3 in C target

    - by JCD
    Hello all! I have some questions about antlr3 with tree grammar in C target. I have almost done my interpretor (functions, variables, boolean and math expressions ok) and i have kept the most difficult statements for the end (like if, switch, etc.) 1) I would like interpreting a simple loop statement: repeat: ^(REPEAT DIGIT stmt); I've seen many examples but nothing about the tree walker (only a topic here with the macros MARK() / REWIND(m) + @init / @after but not working (i've antlr errors: "unexpected node at offset 0")). How can i interpret this statement in C? 2) Same question with a simple if statement: if: ^(IF condition stmt elseifstmt* elsestmt?); The problem is to skip the statement if the condition is false and test the other elseif/else statements. 3) I have some statements which can stop the script (like "break" or "exit"). How can i interrupt the tree walker and skip the following tokens? 4) When a lexer or parser error is detected, antlr returns an error. But i would like to make my homemade error messages. How can i have the line number where parser crashed? Ask me if you want more details. Thanks you very much (and i apologize for my poor english)

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  • What is happening in this T-SQL code?

    - by Ben McCormack
    I'm just starting to learn T-SQL and could use some help in understanding what's going on in a particular block of code. I modified some code in an answer I received in a previous question, and here is the code in question: DECLARE @column_list AS varchar(max) SELECT @column_list = COALESCE(@column_list, ',') + 'SUM(Case When Sku2=' + CONVERT(varchar, Sku2) + ' Then Quantity Else 0 End) As [' + CONVERT(varchar, Sku2) + ' - ' + Convert(varchar,Description) +'],' FROM OrderDetailDeliveryReview Inner Join InvMast on SKU2 = SKU and LocationTypeID=4 GROUP BY Sku2 , Description ORDER BY Sku2 Set @column_list = Left(@column_list,Len(@column_list)-1) Select @column_list ---------------------------------------- 1 row is returned: ,SUM(Case When Sku2=157 Then Quantity Else 0 End) As [157 -..., SUM(Case ... The T-SQL code does exactly what I want, which is to make a single result based on the results of a query, which will then be used in another query. However, I can't figure out how the SELECT @column_list =... statement is putting multiple values into a single string of characters by being inside a SELECT statement. Without the assignment to @column_list, the SELECT statement would simply return multiple rows. How is it that by having the variable within the SELECT statement that the results get "flattened" down into one value? How should I read this T-SQL to properly understand what's going on?

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  • Multi-table Update(MySQL)

    - by smokinguns
    Hey all, I have a question regarding multi-table update(MySQL). Consider table t1 and t2. The PKEY for t1 is 'tid' which is a foreign Key in t2. There is a field "qtyt2" in t2 which depends on a field called "qtyt1" in table t1. Consider the foll SQL statement: UPDATE t2,t1 SET t2.qtyt2=IF(( t2.qtyt2- t1.qtyt1 )<0,0,( t2.qtyt2- t1.qtyt1 ) ), t1.qtyt1 ="Some value.." where t2.tid="some value.." AND t2.tid=t1.tid In this example qtyt2 depends on qtyt1 for update and the latter itself is updated.Now the result should return 2 if two rows are updated. Is there a guarantee that the fields will be updated in the order in which they appear in the statement( first qtyt2 will be set and then qtyt1).Is it possible that qtyt1 will be set first and then qtyt2? Is the order of tables in the statement important (UPDATE t2, t1 or UPDATE t1,t2)? I found that if I wrote "UPDATE t1,t2" then only t1 would get updated, but on changing the statement to "UPDATE t2,t1" everything worked correctly.

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  • SQL Server 2008: CASE vs IF-ELSE-IF vs GOTO

    - by Saharsh Shah
    I have some rules in my application and I have written the business logic of that rules in my procedure. At the time of creation of procedure I came to know that CASE statement won't work in my scenario. So I have tried two ways to perform same operations (using IF-ELSE-IF or GOTO) shown as below. Method 1 Using IF-ELSE-IF conditions: DECLARE @V_RuleId SMALLINT; IF (@V_RuleId = 1) BEGIN /*My business logic*/ END ELSE IF (@V_RuleId = 2) BEGIN /*My business logic*/ END ELSE IF (@V_RuleId = 3) BEGIN /*My business logic*/ END /* ... ... ... ...*/ ELSE IF (@V_RuleId = 19) BEGIN /*My business logic*/ END ELSE IF (@V_RuleId = 20) BEGIN /*My business logic*/ END Method 2 Using GOTO statement: DECLARE @V_RuleId SMALLINT, @V_Temp VARCHAR(100); SET @V_Temp = 'GOTO RULE' + CONVERT(VARCHAR, @V_RuleId); EXECUTE sp_executesql @V_Temp; RULE1: BEGIN /*My business logic*/ END RULE2: BEGIN /*My business logic*/ END RULE3: BEGIN /*My business logic*/ END /* ... ... ... ...*/ RULE19: BEGIN /*My business logic*/ END RULE20: BEGIN /*My business logic*/ END Today I have 20 rules. It can be increase to any number in future. If I can able to use CASE statement then I have not any problem with performance, but I can't do that so I am worried about the performance of my procedure. Also one thing to be noticed that this procedure will execute very frequently by application. My questions are: Is there any way to use CASE statement in my procedure? If not, which method is best to use in my procedure to improve the performance of my code? Thanks in advance...

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  • select for update problem in jdbc

    - by kartiku
    I'm having a problem with select for update in jdbc. The table i'm trying to update is the smalldb table, i'm having problems-- i'm using select for update which does a lock on the selected row the update statement is -- String updateQ = "UPDATE libra.smalldb SET hIx = ? WHERE name = ?"; the select statement is -- rs = stmt1.executeQuery("SELECT hIx FROM libra.smalldb for update"); rs0 = stmt2.executeQuery("SELECT name,aff FROM libra.smalldb"); the second statement is because i need those fields as well. Here is the complete code -- import java.sql.*; import java.util.ArrayList; import java.util.Collections; public class Jdbcexample1 { /** * @param args */ public static void main(String[] args) { Connection con = null; try { Class.forName("com.mysql.jdbc.Driver").newInstance(); con = DriverManager.getConnection("jdbc:mysql:///test", "root", "*****"); //String url = "jdbc:msql://200.210.220.1:1114/Demo"; //Connection conn = DriverManager.getConnection(url,"",""); Statement stmt1 = con.createStatement(); Statement stmt2 = con.createStatement(); Statement stmt3 = con.createStatement(); Statement stmt4 = con.createStatement(); ResultSet rs0; ResultSet rs; ResultSet rs1; ResultSet rs2; String name; String hIx; int hIxInt; StringBuffer sb = new StringBuffer(); String affiliationSmall; ArrayList<String> affiliation = new ArrayList<String>(); ArrayList<Float> matchValues = new ArrayList<Float>(); ArrayList<Integer> hixValues = new ArrayList<Integer>(); ArrayList<Integer> idValues = new ArrayList<Integer>(); boolean moreFlag = false; String queryString; int tmpIdx; String name1; //get the hix at that index where the similarity is maximum int tmpHidx = 0; int tmpHix = 0; int id = 0; int count; int tmpidIdx = 0; //rs = stmt.executeQuery("SELECT id FROM libra.researchint WHERE id = 910887"); // Get name, affiliation , hIx from smalldb //rs = stmt1.executeQuery("SELECT name,aff,hIx FROM libra.smalldb"); // String cursorName = "OUR_CURSOR"; // stmt1.setCursorName(cursorName); //rs = stmt1.executeQuery("SELECT name,aff,hIx FROM libra.smalldb for update"); rs = stmt1.executeQuery("SELECT hIx FROM libra.smalldb for update"); rs0 = stmt2.executeQuery("SELECT name,aff FROM libra.smalldb"); while ( rs.next() && rs0.next() ) { //String lastName = rs.getString("id"); hIx = rs.getString("hIx"); hIxInt = Integer.parseInt(hIx); //if hIx if (hIxInt==-1) continue; //name = rs.getString("name"); name = rs0.getString("name"); name1 = new String(name); System.out.println(name); //affiliationSmall = rs.getString("aff"); affiliationSmall = rs0.getString("aff"); //name = "\"" +name+ "\""; // Get matching names from large faculty table //String queryString = "SELECT id,name,hIx FROM libra.faculty WHERE name = " +name; //name = does not work names are similar but not same (in faculty and // smalldb) String query = "SELECT id,name,hIx FROM libra.faculty WHERE name like ?"; //String query = "SELECT id,name,hIx FROM libra.faculty for update of hIx WHERE name like ?"; PreparedStatement prepStmt = con.prepareStatement(query); String[] nameArr = name.split(" "); StringBuffer tmpSb = new StringBuffer(); for(int idx = 0;idx<nameArr.length;idx++) { tmpSb.append(nameArr[idx] + "%"); } name = tmpSb.toString(); prepStmt.setString(1, name); rs1 = prepStmt.executeQuery(); //Try to get matching names from faculty big db //Execute the query on faculty table //rs1 = stmt2.executeQuery(queryString); if(rs1.isClosed()) continue; count = 0; matchValues.clear(); affiliation.clear(); while(rs1.next()) { //name = rs1.getString("name"); id = Integer.parseInt(rs1.getString("id")); //idValues.add(id); tmpHix = Integer.parseInt(rs1.getString("hIx")); queryString = "SELECT aff FROM libra.affiliation WHERE id = "+id; rs2 = stmt3.executeQuery(queryString); //affiliation = rs1.getString("aff"); sb.delete(0, sb.length()); while (rs2.next()) { //Concatenate it to the same string using a stringbuffer sb.append(rs2.getString("aff")); //affiliation.add(rs2.getString("aff")); } affiliation.add(sb.toString()); count++; // if(count1) // { // moreFlag = true; // //Call fuzzy match function, store the distance values and select the // //affiliation that has the minimum distance from affiliationSmall // // //problem is here, affiliation.get Index: 2, Size: 2 // // matchValues.add(fuzzyMatch(affiliationSmall,affiliation.get(count))); // hixValues.add(tmpHix); // idValues.add(id); // } }//end of while rs1 -> faculty rs1.close(); int idx = 0; if(count>1) { moreFlag = true; //Call fuzzy match function, store the distance values and select the //affiliation that has the minimum distance from affiliationSmall //problem is here, affiliation.get Index: 2, Size: 2 matchValues.add(fuzzyMatch(affiliationSmall,affiliation.get(idx))); hixValues.add(tmpHix); idValues.add(id); idx++; } if(moreFlag) { Object obj = Collections.max(matchValues); float maxVal = Float.parseFloat(obj.toString()); //int tmpIdx = matchValues.indexOf(new Float(maxVal)); //get the index at which similarity between affiliation strings is maximum, //as returned by fuzzyMatch //int tmpIdx = matchValues.indexOf(maxVal); tmpIdx = matchValues.indexOf(maxVal); //get the hix at that index where the similarity is maximum //int tmpHidx = hixValues.get(tmpIdx); tmpHidx = hixValues.get(tmpIdx); tmpidIdx = idValues.get(tmpIdx); //update the smalldb table String updateQ = "UPDATE libra.smalldb SET hIx = ? WHERE name = ?"; //String updateQ = "UPDATE libra.smalldb SET hIx = ? WHERE current of "+cursorName; //PreparedStatement prepStmt1 = con.prepareStatement("UPDATE libra.smalldb SET hIx = ? WHERE current of "+cursorName); PreparedStatement prepStmt1 = con.prepareStatement(updateQ); //PreparedStatement prepStmt1 = con.prepareStatement(updateQ); prepStmt1.setString(2, name1); prepStmt1.setString(1, Integer.toString(tmpHidx)); prepStmt1.executeUpdate(updateQ); //prepStmt1.execute(); //stmt4.executeUpdate(updateQ); }//end of if //For matching names get the affiliation based on id from affiliation table //con.close(); //System.out.println(lastName); System.out.println(name); }//end of while rs -> smalldb rs.close(); // String updateQ = "UPDATE libra.smalldb1 SET hIx = "+Integer.toString(tmpHidx)+ "WHERE id = "+Integer.toString(tmpidIdx); // stmt4.executeUpdate(updateQ); con.close(); } catch (Exception e) { System.err.println("Got an exception! "); System.err.println(e.getMessage()); e.printStackTrace(); } } public static float fuzzyMatch(String affiliationSmall, String affiliation) { //float distance = 0; String[] temp = null; temp = affiliationSmall.split(" "); int index; //int index1 = affiliation.indexOf(affiliationSmall); int matchCount = 0; for (int idx = 0;idx<temp.length; idx++) { index = affiliation.indexOf(temp[idx]); if (index!=-1) { matchCount++; } } float tmpFloat = matchCount/temp.length; //int[] aff1= new int[affiliation1.length()]; //int[] aff2 = new int[affiliation2.length()]; return tmpFloat; } } i think it is because of the second select statement (rs0) Here is the error- Got an exception! You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '?' at line 1 com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '?' at line 1 at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source) at java.lang.reflect.Constructor.newInstance(Unknown Source) at com.mysql.jdbc.Util.handleNewInstance(Util.java:409) at com.mysql.jdbc.Util.getInstance(Util.java:384) at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1054) at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3562) at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3494) at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1960) at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2114) at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2690) at com.mysql.jdbc.StatementImpl.executeUpdate(StatementImpl.java:1648) at com.mysql.jdbc.StatementImpl.executeUpdate(StatementImpl.java:1567) at Jdbcexample1.main(Jdbcexample1.java:184)

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  • fortran complications passing arrays in function

    - by user1514188
    I'm trying to write a program to calculate a cross product of two vectors (input is of "real" type, so for example [1.3 3.4 1,5]). But I keep getting numerous errors: program Q3CW implicit none REAL :: matA(3), matB(3) REAL :: A11, A12, A13 REAL :: B11, B12, B13 real :: productc(3), answer(3) read*,A11, A12, A13 read*,B11, B12, B13 matA = (/A11, A12, A13/) matB = (/B11, B12, B13/) answer = productc(matA, matB) print*,'Answer = ', answer(1), answer(2), answer(3) end program real function productc(matIn1, matIn2) real, dimension(3) :: matIn1, matIn2 productc(1)=(/matIn1(2)*matIn2(3)-matIn1(3)*matIn2(2)/) productc(2)=(/matIn1(3)*matIn2(1)-matIn1(1)*matIn2(3)/) productc(3)=(/matIn1(1)*matIn2(2)-matIn1(2)*matIn2(1)/) end function This is the error I get: Error: Q33333.f95(20) : Statement function definition for pre-existing procedure PRODUCTC; detected at )@= Error: Q33333.f95(21) : Statement function definition for pre-existing procedure PRODUCTC; detected at )@= Error: Q33333.f95(22) : Statement function definition for pre-existing procedure PRODUCTC; detected at )@= Warning: Q33333.f95(23) : Function PRODUCTC has not been assigned a value; detected at FUNCTION@<end-of-statement> Build Result Error(3) Warning(1) Extension(0) Any idea what the problem could be ?

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