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  • PostgreSQL triggers and passing parameters

    - by iandouglas
    This is a multi-part question. I have a table similar to this: CREATE TABLE sales_data ( Company character(50), Contract character(50), top_revenue_sum integer, top_revenue_sales integer, last_sale timestamp) ; I'd like to create a trigger for new inserts into this table, something like this: CREATE OR REPLACE FUNCTION add_contract() RETURNS VOID DECLARE myCompany character(50), myContract character(50), BEGIN myCompany = TG_ARGV[0]; myContract = TG_ARGV[1]; IF (TG_OP = 'INSERT') THEN EXECUTE 'CREATE TABLE salesdata_' || $myCompany || '_' || $myContract || ' ( sale_amount integer, updated TIMESTAMP not null, some_data varchar(32), country varchar(2) ) ;' EXECUTE 'CREATE TRIGGER update_sales_data BEFORE INSERT OR DELETE ON salesdata_' || $myCompany || '_' || $myContract || ' FOR EACH ROW EXECUTE update_sales_data( ' || $myCompany || ',' || $myContract || ', revenue);' ; END IF; END; $add_contract$ LANGUAGE plpgsql; CREATE TRIGGER add_contract AFTER INSERT ON sales_data FOR EACH ROW EXECUTE add_contract() ; Basically, every time I insert a new row into sales_data, I want to generate a new table where the name of the table will be defined as something like "salesdata_Company_Contract" So my first question is how can I pass the Company and Contract data to the trigger so it can be passed to the add_contract() stored procedure? From my stored procedure, you'll see that I also want to update the original sales_data table whenever new data is inserted into the salesdata_Company_Contract table. This trigger will do something like this: CREATE OR REPLACE FUNCTION update_sales_data() RETURNS trigger as $update_sales_data$ DECLARE myCompany character(50) NOT NULL, myContract character(50) NOT NULL, myRevenue integer NOT NULL BEGIN myCompany = TG_ARGV[0] ; myContract = TG_ARGV[1] ; myRevenue = TG_ARGV[2] ; IF (TG_OP = 'INSERT') THEN UPDATE sales_data SET top_revenue_sales = top_revenue_sales + 1, top_revenue_sum = top_revenue_sum + $myRevenue, updated = now() WHERE Company = $myCompany AND Contract = $myContract ; ELSIF (TG_OP = 'DELETE') THEN UPDATE sales_data SET top_revenue_sales = top_revenue_sales - 1, top_revenue_sum = top_revenue_sum - $myRevenue, updated = now() WHERE Company = $myCompany AND Contract = $myContract ; END IF; END; $update_sales_data$ LANGUAGE plpgsql; This will, of course, require that I pass several parameters around within these stored procedures and triggers, and I'm not sure (a) if this is even possible, or (b) practical, or (c) best practice and we should just put this logic into our other software instead of asking the database to do this work for us. To keep our table sizes down, as we'll have hundreds of thousands of transactions per day, we've decided to partition our data using the Company and Contract strings as part of the table names themselves so they're all very small in size; file IO for us is faster and we felt we'd get better performance. Thanks for any thoughts or direction. My thinking, now that I've written all of this out, is that maybe we need to write stored procedures where we pass our insert data as parameters, and call that from our other software, and have the stored procedure do the insert into "sales_data" then create the other table. Then, have a second stored procedure to insert new data into the salesdata_Company_Contract tables, where the table name is passed to the stored proc as a parameter, and again have that stored proc do the insert, then update the main sales_data table afterward. What approach would you take?

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  • SQL SERVER – Shrinking Database is Bad – Increases Fragmentation – Reduces Performance

    - by pinaldave
    Earlier, I had written two articles related to Shrinking Database. I wrote about why Shrinking Database is not good. SQL SERVER – SHRINKDATABASE For Every Database in the SQL Server SQL SERVER – What the Business Says Is Not What the Business Wants I received many comments on Why Database Shrinking is bad. Today we will go over a very interesting example that I have created for the same. Here are the quick steps of the example. Create a test database Create two tables and populate with data Check the size of both the tables Size of database is very low Check the Fragmentation of one table Fragmentation will be very low Truncate another table Check the size of the table Check the fragmentation of the one table Fragmentation will be very low SHRINK Database Check the size of the table Check the fragmentation of the one table Fragmentation will be very HIGH REBUILD index on one table Check the size of the table Size of database is very HIGH Check the fragmentation of the one table Fragmentation will be very low Here is the script for the same. USE MASTER GO CREATE DATABASE ShrinkIsBed GO USE ShrinkIsBed GO -- Name of the Database and Size SELECT name, (size*8) Size_KB FROM sys.database_files GO -- Create FirstTable CREATE TABLE FirstTable (ID INT, FirstName VARCHAR(100), LastName VARCHAR(100), City VARCHAR(100)) GO -- Create Clustered Index on ID CREATE CLUSTERED INDEX [IX_FirstTable_ID] ON FirstTable ( [ID] ASC ) ON [PRIMARY] GO -- Create SecondTable CREATE TABLE SecondTable (ID INT, FirstName VARCHAR(100), LastName VARCHAR(100), City VARCHAR(100)) GO -- Create Clustered Index on ID CREATE CLUSTERED INDEX [IX_SecondTable_ID] ON SecondTable ( [ID] ASC ) ON [PRIMARY] GO -- Insert One Hundred Thousand Records INSERT INTO FirstTable (ID,FirstName,LastName,City) SELECT TOP 100000 ROW_NUMBER() OVER (ORDER BY a.name) RowID, 'Bob', CASE WHEN ROW_NUMBER() OVER (ORDER BY a.name)%2 = 1 THEN 'Smith' ELSE 'Brown' END, CASE WHEN ROW_NUMBER() OVER (ORDER BY a.name)%10 = 1 THEN 'New York' WHEN ROW_NUMBER() OVER (ORDER BY a.name)%10 = 5 THEN 'San Marino' WHEN ROW_NUMBER() OVER (ORDER BY a.name)%10 = 3 THEN 'Los Angeles' ELSE 'Houston' END FROM sys.all_objects a CROSS JOIN sys.all_objects b GO -- Name of the Database and Size SELECT name, (size*8) Size_KB FROM sys.database_files GO -- Insert One Hundred Thousand Records INSERT INTO SecondTable (ID,FirstName,LastName,City) SELECT TOP 100000 ROW_NUMBER() OVER (ORDER BY a.name) RowID, 'Bob', CASE WHEN ROW_NUMBER() OVER (ORDER BY a.name)%2 = 1 THEN 'Smith' ELSE 'Brown' END, CASE WHEN ROW_NUMBER() OVER (ORDER BY a.name)%10 = 1 THEN 'New York' WHEN ROW_NUMBER() OVER (ORDER BY a.name)%10 = 5 THEN 'San Marino' WHEN ROW_NUMBER() OVER (ORDER BY a.name)%10 = 3 THEN 'Los Angeles' ELSE 'Houston' END FROM sys.all_objects a CROSS JOIN sys.all_objects b GO -- Name of the Database and Size SELECT name, (size*8) Size_KB FROM sys.database_files GO -- Check Fragmentations in the database SELECT avg_fragmentation_in_percent, fragment_count FROM sys.dm_db_index_physical_stats (DB_ID(), OBJECT_ID('SecondTable'), NULL, NULL, 'LIMITED') GO Let us check the table size and fragmentation. Now let us TRUNCATE the table and check the size and Fragmentation. USE MASTER GO CREATE DATABASE ShrinkIsBed GO USE ShrinkIsBed GO -- Name of the Database and Size SELECT name, (size*8) Size_KB FROM sys.database_files GO -- Create FirstTable CREATE TABLE FirstTable (ID INT, FirstName VARCHAR(100), LastName VARCHAR(100), City VARCHAR(100)) GO -- Create Clustered Index on ID CREATE CLUSTERED INDEX [IX_FirstTable_ID] ON FirstTable ( [ID] ASC ) ON [PRIMARY] GO -- Create SecondTable CREATE TABLE SecondTable (ID INT, FirstName VARCHAR(100), LastName VARCHAR(100), City VARCHAR(100)) GO -- Create Clustered Index on ID CREATE CLUSTERED INDEX [IX_SecondTable_ID] ON SecondTable ( [ID] ASC ) ON [PRIMARY] GO -- Insert One Hundred Thousand Records INSERT INTO FirstTable (ID,FirstName,LastName,City) SELECT TOP 100000 ROW_NUMBER() OVER (ORDER BY a.name) RowID, 'Bob', CASE WHEN ROW_NUMBER() OVER (ORDER BY a.name)%2 = 1 THEN 'Smith' ELSE 'Brown' END, CASE WHEN ROW_NUMBER() OVER (ORDER BY a.name)%10 = 1 THEN 'New York' WHEN ROW_NUMBER() OVER (ORDER BY a.name)%10 = 5 THEN 'San Marino' WHEN ROW_NUMBER() OVER (ORDER BY a.name)%10 = 3 THEN 'Los Angeles' ELSE 'Houston' END FROM sys.all_objects a CROSS JOIN sys.all_objects b GO -- Name of the Database and Size SELECT name, (size*8) Size_KB FROM sys.database_files GO -- Insert One Hundred Thousand Records INSERT INTO SecondTable (ID,FirstName,LastName,City) SELECT TOP 100000 ROW_NUMBER() OVER (ORDER BY a.name) RowID, 'Bob', CASE WHEN ROW_NUMBER() OVER (ORDER BY a.name)%2 = 1 THEN 'Smith' ELSE 'Brown' END, CASE WHEN ROW_NUMBER() OVER (ORDER BY a.name)%10 = 1 THEN 'New York' WHEN ROW_NUMBER() OVER (ORDER BY a.name)%10 = 5 THEN 'San Marino' WHEN ROW_NUMBER() OVER (ORDER BY a.name)%10 = 3 THEN 'Los Angeles' ELSE 'Houston' END FROM sys.all_objects a CROSS JOIN sys.all_objects b GO -- Name of the Database and Size SELECT name, (size*8) Size_KB FROM sys.database_files GO -- Check Fragmentations in the database SELECT avg_fragmentation_in_percent, fragment_count FROM sys.dm_db_index_physical_stats (DB_ID(), OBJECT_ID('SecondTable'), NULL, NULL, 'LIMITED') GO You can clearly see that after TRUNCATE, the size of the database is not reduced and it is still the same as before TRUNCATE operation. After the Shrinking database operation, we were able to reduce the size of the database. If you notice the fragmentation, it is considerably high. The major problem with the Shrink operation is that it increases fragmentation of the database to very high value. Higher fragmentation reduces the performance of the database as reading from that particular table becomes very expensive. One of the ways to reduce the fragmentation is to rebuild index on the database. Let us rebuild the index and observe fragmentation and database size. -- Rebuild Index on FirstTable ALTER INDEX IX_SecondTable_ID ON SecondTable REBUILD GO -- Name of the Database and Size SELECT name, (size*8) Size_KB FROM sys.database_files GO -- Check Fragmentations in the database SELECT avg_fragmentation_in_percent, fragment_count FROM sys.dm_db_index_physical_stats (DB_ID(), OBJECT_ID('SecondTable'), NULL, NULL, 'LIMITED') GO You can notice that after rebuilding, Fragmentation reduces to a very low value (almost same to original value); however the database size increases way higher than the original. Before rebuilding, the size of the database was 5 MB, and after rebuilding, it is around 20 MB. Regular rebuilding the index is rebuild in the same user database where the index is placed. This usually increases the size of the database. Look at irony of the Shrinking database. One person shrinks the database to gain space (thinking it will help performance), which leads to increase in fragmentation (reducing performance). To reduce the fragmentation, one rebuilds index, which leads to size of the database to increase way more than the original size of the database (before shrinking). Well, by Shrinking, one did not gain what he was looking for usually. Rebuild indexing is not the best suggestion as that will create database grow again. I have always remembered the excellent post from Paul Randal regarding Shrinking the database is bad. I suggest every one to read that for accuracy and interesting conversation. Let us run following script where we Shrink the database and REORGANIZE. -- Name of the Database and Size SELECT name, (size*8) Size_KB FROM sys.database_files GO -- Check Fragmentations in the database SELECT avg_fragmentation_in_percent, fragment_count FROM sys.dm_db_index_physical_stats (DB_ID(), OBJECT_ID('SecondTable'), NULL, NULL, 'LIMITED') GO -- Shrink the Database DBCC SHRINKDATABASE (ShrinkIsBed); GO -- Name of the Database and Size SELECT name, (size*8) Size_KB FROM sys.database_files GO -- Check Fragmentations in the database SELECT avg_fragmentation_in_percent, fragment_count FROM sys.dm_db_index_physical_stats (DB_ID(), OBJECT_ID('SecondTable'), NULL, NULL, 'LIMITED') GO -- Rebuild Index on FirstTable ALTER INDEX IX_SecondTable_ID ON SecondTable REORGANIZE GO -- Name of the Database and Size SELECT name, (size*8) Size_KB FROM sys.database_files GO -- Check Fragmentations in the database SELECT avg_fragmentation_in_percent, fragment_count FROM sys.dm_db_index_physical_stats (DB_ID(), OBJECT_ID('SecondTable'), NULL, NULL, 'LIMITED') GO You can see that REORGANIZE does not increase the size of the database or remove the fragmentation. Again, I no way suggest that REORGANIZE is the solution over here. This is purely observation using demo. Read the blog post of Paul Randal. Following script will clean up the database -- Clean up USE MASTER GO ALTER DATABASE ShrinkIsBed SET SINGLE_USER WITH ROLLBACK IMMEDIATE GO DROP DATABASE ShrinkIsBed GO There are few valid cases of the Shrinking database as well, but that is not covered in this blog post. We will cover that area some other time in future. Additionally, one can rebuild index in the tempdb as well, and we will also talk about the same in future. Brent has written a good summary blog post as well. Are you Shrinking your database? Well, when are you going to stop Shrinking it? Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Index, SQL Performance, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQLServer, T SQL, Technology

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  • Combination of Operating Mode and Commit Strategy

    - by Kevin Yang
    If you want to populate a source into multiple targets, you may also want to ensure that every row from the source affects all targets uniformly (or separately). Let’s consider the Example Mapping below. If a row from SOURCE causes different changes in multiple targets (TARGET_1, TARGET_2 and TARGET_3), for example, it can be successfully inserted into TARGET_1 and TARGET_3, but failed to be inserted into TARGET_2, and the current Mapping Property TLO (target load order) is “TARGET_1 -> TARGET_2 -> TARGET_3”. What should Oracle Warehouse Builder do, in order to commit the appropriate data to all affected targets at the same time? If it doesn’t behave as you intended, the data could become inaccurate and possibly unusable.                                               Example Mapping In OWB, we can use Mapping Configuration Commit Strategies and Operating Modes together to achieve this kind of requirements. Below we will explore the combination of these two features and how they affect the results in the target tables Before going to the example, let’s review some of the terms we will be using (Details can be found in white paper Oracle® Warehouse Builder Data Modeling, ETL, and Data Quality Guide11g Release 2): Operating Modes: Set-Based Mode: Warehouse Builder generates a single SQL statement that processes all data and performs all operations. Row-Based Mode: Warehouse Builder generates statements that process data row by row. The select statement is in a SQL cursor. All subsequent statements are PL/SQL. Row-Based (Target Only) Mode: Warehouse Builder generates a cursor select statement and attempts to include as many operations as possible in the cursor. For each target, Warehouse Builder inserts each row into the target separately. Commit Strategies: Automatic: Warehouse Builder loads and then automatically commits data based on the mapping design. If the mapping has multiple targets, Warehouse Builder commits and rolls back each target separately and independently of other targets. Use the automatic commit when the consequences of multiple targets being loaded unequally are not great or are irrelevant. Automatic correlated: It is a specialized type of automatic commit that applies to PL/SQL mappings with multiple targets only. Warehouse Builder considers all targets collectively and commits or rolls back data uniformly across all targets. Use the correlated commit when it is important to ensure that every row in the source affects all affected targets uniformly. Manual: select manual commit control for PL/SQL mappings when you want to interject complex business logic, perform validations, or run other mappings before committing data. Combination of the commit strategy and operating mode To understand the effects of each combination of operating mode and commit strategy, I’ll illustrate using the following example Mapping. Firstly we insert 100 rows into the SOURCE table and make sure that the 99th row and 100th row have the same ID value. And then we create a unique key constraint on ID column for TARGET_2 table. So while running the example mapping, OWB tries to load all 100 rows to each of the targets. But the mapping should fail to load the 100th row to TARGET_2, because it will violate the unique key constraint of table TARGET_2. With different combinations of Commit Strategy and Operating Mode, here are the results ¦ Set-based/ Correlated Commit: Configuration of Example mapping:                                                     Result:                                                      What’s happening: A single error anywhere in the mapping triggers the rollback of all data. OWB encounters the error inserting into Target_2, it reports an error for the table and does not load the row. OWB rolls back all the rows inserted into Target_1 and does not attempt to load rows to Target_3. No rows are added to any of the target tables. ¦ Row-based/ Correlated Commit: Configuration of Example mapping:                                                   Result:                                                  What’s happening: OWB evaluates each row separately and loads it to all three targets. Loading continues in this way until OWB encounters an error loading row 100th to Target_2. OWB reports the error and does not load the row. It rolls back the row 100th previously inserted into Target_1 and does not attempt to load row 100 to Target_3. Then, if there are remaining rows, OWB will continue loading them, resuming with loading rows to Target_1. The mapping completes with 99 rows inserted into each target. ¦ Set-based/ Automatic Commit: Configuration of Example mapping: Result: What’s happening: When OWB encounters the error inserting into Target_2, it does not load any rows and reports an error for the table. It does, however, continue to insert rows into Target_3 and does not roll back the rows previously inserted into Target_1. The mapping completes with one error message for Target_2, no rows inserted into Target_2, and 100 rows inserted into Target_1 and Target_3 separately. ¦ Row-based/Automatic Commit: Configuration of Example mapping: Result: What’s happening: OWB evaluates each row separately for loading into the targets. Loading continues in this way until OWB encounters an error loading row 100 to Target_2 and reports the error. OWB does not roll back row 100th from Target_1, does insert it into Target_3. If there are remaining rows, it will continue to load them. The mapping completes with 99 rows inserted into Target_2 and 100 rows inserted into each of the other targets. Note: Automatic Correlated commit is not applicable for row-based (target only). If you design a mapping with the row-based (target only) and correlated commit combination, OWB runs the mapping but does not perform the correlated commit. In set-based mode, correlated commit may impact the size of your rollback segments. Space for rollback segments may be a concern when you merge data (insert/update or update/insert). Correlated commit operates transparently with PL/SQL bulk processing code. The correlated commit strategy is not available for mappings run in any mode that are configured for Partition Exchange Loading or that include a Queue, Match Merge, or Table Function operator. If you want to practice in your own environment, you can follow the steps: 1. Import the MDL file: commit_operating_mode.mdl 2. Fix the location for oracle module ORCL and deploy all tables under it. 3. Insert sample records into SOURCE table, using below plsql code: begin     for i in 1..99     loop         insert into source values(i, 'col_'||i);     end loop;     insert into source values(99, 'col_99'); end; 4. Configure MAPPING_1 to any combinations of operating mode and commit strategy you want to test. And make sure feature TLO of mapping is open. 5. Deploy Mapping “MAPPING_1”. 6. Run the mapping and check the result.

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  • How to archive data from a table to a local or remote database in SQL 2005 and SQL 2008

    - by simonsabin
    Often you have the need to archive data from a table. This leads to a number of challenges 1. How can you do it without impacting users 2. How can I make it transactionally consistent, i.e. the data I put in the archive is the data I remove from the main table 3. How can I get it to perform well Points 1 is very much tied to point 3. If it doesn't perform well then the delete of data is going to cause lots of locks and thus potentially blocking. For points 1 and 3 refer to my previous posts DELETE-TOP-x-rows-avoiding-a-table-scan and UPDATE-and-DELETE-TOP-and-ORDER-BY---Part2. In essence you need to be removing small chunks of data from your table and you want to do that avoiding a table scan. So that deals with the delete approach but archiving is about inserting that data somewhere else. Well in SQL 2008 they introduced a new feature INSERT over DML (Data Manipulation Language, i.e. SQL statements that change data), or composable DML. The ability to nest DML statements within themselves, so you can past the results of an insert to an update to a merge. I've mentioned this before here SQL-Server-2008---MERGE-and-optimistic-concurrency. This feature is currently limited to being able to consume the results of a DML statement in an INSERT statement. There are many restrictions which you can find here http://msdn.microsoft.com/en-us/library/ms177564.aspx look for the section "Inserting Data Returned From an OUTPUT Clause Into a Table" Even with the restrictions what we can do is consume the OUTPUT from a DELETE and INSERT the results into a table in another database. Note that in BOL it refers to not being able to use a remote table, remote means a table on another SQL instance. To show this working use this SQL to setup two databases foo and fooArchive create database foo go --create the source table fred in database foo select * into foo..fred from sys.objects go create database fooArchive go if object_id('fredarchive',DB_ID('fooArchive')) is null begin     select getdate() ArchiveDate,* into fooArchive..FredArchive from sys.objects where 1=2       end go And then we can use this simple statement to archive the data insert into fooArchive..FredArchive select getdate(),d.* from (delete top (1)         from foo..Fred         output deleted.*) d         go In this statement the delete can be any delete statement you wish so if you are deleting by ids or a range of values then you can do that. Refer to the DELETE-TOP-x-rows-avoiding-a-table-scan post to ensure that your delete is going to perform. The last thing you want to do is to perform 100 deletes each with 5000 records for each of those deletes to do a table scan. For a solution that works for SQL2005 or if you want to archive to a different server then you can use linked servers or SSIS. This example shows how to do it with linked servers. [ONARC-LAP03] is the source server. begin transaction insert into fooArchive..FredArchive select getdate(),d.* from openquery ([ONARC-LAP03],'delete top (1)                     from foo..Fred                     output deleted.*') d commit transaction and to prove the transactions work try, you should get the same number of records before and after. select (select count(1) from foo..Fred) fred        ,(select COUNT(1) from fooArchive..FredArchive ) fredarchive   begin transaction insert into fooArchive..FredArchive select getdate(),d.* from openquery ([ONARC-LAP03],'delete top (1)                     from foo..Fred                     output deleted.*') d rollback transaction   select (select count(1) from foo..Fred) fred        ,(select COUNT(1) from fooArchive..FredArchive ) fredarchive The transactions are very important with this solution. Look what happens when you don't have transactions and an error occurs   select (select count(1) from foo..Fred) fred        ,(select COUNT(1) from fooArchive..FredArchive ) fredarchive   insert into fooArchive..FredArchive select getdate(),d.* from openquery ([ONARC-LAP03],'delete top (1)                     from foo..Fred                     output deleted.*                     raiserror (''Oh doo doo'',15,15)') d                     select (select count(1) from foo..Fred) fred        ,(select COUNT(1) from fooArchive..FredArchive ) fredarchive Before running this think what the result would be. I got it wrong. What seems to happen is that the remote query is executed as a transaction, the error causes that to rollback. However the results have already been sent to the client and so get inserted into the

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  • SQL SERVER – Weekly Series – Memory Lane – #032

    - 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 Complete Series of Database Coding Standards and Guidelines SQL SERVER Database Coding Standards and Guidelines – Introduction SQL SERVER – Database Coding Standards and Guidelines – Part 1 SQL SERVER – Database Coding Standards and Guidelines – Part 2 SQL SERVER Database Coding Standards and Guidelines Complete List Download Explanation and Example – SELF JOIN When all of the data you require is contained within a single table, but data needed to extract is related to each other in the table itself. Examples of this type of data relate to Employee information, where the table may have both an Employee’s ID number for each record and also a field that displays the ID number of an Employee’s supervisor or manager. To retrieve the data tables are required to relate/join to itself. Insert Multiple Records Using One Insert Statement – Use of UNION ALL This is very interesting question I have received from new developer. How can I insert multiple values in table using only one insert? Now this is interesting question. When there are multiple records are to be inserted in the table following is the common way using T-SQL. Function to Display Current Week Date and Day – Weekly Calendar Straight blog post with script to find current week date and day based on the parameters passed in the function.  2008 In my beginning years, I have almost same confusion as many of the developer had in their earlier years. Here are two of the interesting question which I have attempted to answer in my early year. Even if you are experienced developer may be you will still like to read following two questions: Order Of Column In Index Order of Conditions in WHERE Clauses Example of DISTINCT in Aggregate Functions Have you ever used DISTINCT with the Aggregation Function? Here is a simple example about how users can do it. Create a Comma Delimited List Using SELECT Clause From Table Column Straight to script example where I explained how to do something easy and quickly. Compound Assignment Operators SQL SERVER 2008 has introduced new concept of Compound Assignment Operators. Compound Assignment Operators are available in many other programming languages for quite some time. Compound Assignment Operators is operator where variables are operated upon and assigned on the same line. PIVOT and UNPIVOT Table Examples Here is a very interesting question – the answer to the question can be YES or NO both. “If we PIVOT any table and UNPIVOT that table do we get our original table?” Read the blog post to get the explanation of the question above. 2009 What is Interim Table – Simple Definition of Interim Table The interim table is a table that is generated by joining two tables and not the final result table. In other words, when two tables are joined they create an interim table as resultset but the resultset is not final yet. It may be possible that more tables are about to join on the interim table, and more operations are still to be applied on that table (e.g. Order By, Having etc). Besides, it may be possible that there is no interim table; sometimes final table is what is generated when the query is run. 2010 Stored Procedure and Transactions If Stored Procedure is transactional then, it should roll back complete transactions when it encounters any errors. Well, that does not happen in this case, which proves that Stored Procedure does not only provide just the transactional feature to a batch of T-SQL. Generate Database Script for SQL Azure When talking about SQL Azure the most common complaint I hear is that the script generated from stand-along SQL Server database is not compatible with SQL Azure. This was true for some time for sure but not any more. If you have SQL Server 2008 R2 installed you can follow the guideline below to generate a script which is compatible with SQL Azure. Convert IN to EXISTS – Performance Talk It is NOT necessary that every time when IN is replaced by EXISTS it gives better performance. However, in our case listed above it does for sure give better performance. You can read about this subject in the associated blog post. Subquery or Join – Various Options – SQL Server Engine Knows the Best Every single time whenever there is a performance tuning exercise, I hear the conversation from developer where some prefer subquery and some prefer join. In this two part blog post, I explain the same in the detail with examples. Part 1 | Part 2 Merge Operations – Insert, Update, Delete in Single Execution MERGE is a new feature that provides an efficient way to do multiple DML operations. In earlier versions of SQL Server, we had to write separate statements to INSERT, UPDATE, or DELETE data based on certain conditions; however, at present, by using the MERGE statement, we can include the logic of such data changes in one statement that even checks when the data is matched and then just update it, and similarly, when the data is unmatched, it is inserted. 2011 Puzzle – Statistics are not updated but are Created Once Here is the quick scenario about my setup. Create Table Insert 1000 Records Check the Statistics Now insert 10 times more 10,000 indexes Check the Statistics – it will be NOT updated – WHY? Question to You – When to use Function and When to use Stored Procedure Personally, I believe that they are both different things - they cannot be compared. I can say, it will be like comparing apples and oranges. Each has its own unique use. However, they can be used interchangeably at many times and in real life (i.e., production environment). I have personally seen both of these being used interchangeably many times. This is the precise reason for asking this question. 2012 In year 2012 I had two interesting series ran on the blog. If there is no fun in learning, the learning becomes a burden. For the same reason, I had decided to build a three part quiz around SEQUENCE. The quiz was to identify the next value of the sequence. I encourage all of you to take part in this fun quiz. Guess the Next Value – Puzzle 1 Guess the Next Value – Puzzle 2 Guess the Next Value – Puzzle 3 Guess the Next Value – Puzzle 4 Simple Example to Configure Resource Governor – Introduction to Resource Governor Resource Governor is a feature which can manage SQL Server Workload and System Resource Consumption. We can limit the amount of CPU and memory consumption by limiting /governing /throttling on the SQL Server. If there are different workloads running on SQL Server and each of the workload needs different resources or when workloads are competing for resources with each other and affecting the performance of the whole server resource governor is a very important task. Tricks to Replace SELECT * with Column Names – SQL in Sixty Seconds #017 – Video  Retrieves unnecessary columns and increases network traffic When a new columns are added views needs to be refreshed manually Leads to usage of sub-optimal execution plan Uses clustered index in most of the cases instead of using optimal index It is difficult to debug SQL SERVER – Load Generator – Free Tool From CodePlex The best part of this SQL Server Load Generator is that users can run multiple simultaneous queries again SQL Server using different login account and different application name. The interface of the tool is extremely easy to use and very intuitive as well. A Puzzle – Swap Value of Column Without Case Statement Let us assume there is a single column in the table called Gender. The challenge is to write a single update statement which will flip or swap the value in the column. For example if the value in the gender column is ‘male’ swap it with ‘female’ and if the value is ‘female’ swap it with ‘male’. 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

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  • JPA/Hibernate and MySQL transaction isolation level

    - by armandino
    I have a native query that does a batch insert into a MySQL database: String sql = "insert into t1 (a, b) select x, y from t2 where x = 'foo'"; EntityTransaction tx = entityManager.getTransaction(); try { tx.begin(); int rowCount = entityManager.createNativeQuery(sql).executeUpdate(); tx.commit(); return rowCount; } catch(Exception ex) { tx.rollback(); log.error(...); } This query causes a deadlock: while it reads from t2 with insert .. select, another process tries to insert a row into t2. I don't care about the consistency of reads from t2 when doing an insert .. select and want to set the transaction isolation level to READ_UNCOMMITTED. How do I go about setting it in JPA backed by Hibernate?

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  • Create Chemistry Equations and Diagrams in Word

    - by Matthew Guay
    Microsoft Word is a great tool for formatting text, but what if you want to insert a chemistry formula or diagram?  Thanks to a new free add-in for Word, you can now insert high-quality chemistry formulas and diagrams directly from the Ribbon in Word. Microsoft’s new Education Labs has recently released the new Chemistry Add-in for Word 2007 and 2010.  This free download adds support for entering and editing chemistry symbols, diagrams, and formulas using the standard XML based Chemical Markup Language.  You can convert any chemical name, such as benzene, or formula, such as H2O, into a chemical diagram, standard name, or formula.  Whether you’re a professional chemist, just taking chemistry in school, or simply curious about the makeup of Citric Acid, this add-in is an exciting way to bring chemistry to your computer. This add-in works great on Word 2007 and 2010, including the 64 bit version of Word 2010.  Please note that the current version is still in beta, so only run it if you are comfortable running beta products. Getting Started Download the Chemistry add-in from Microsoft Education Labs (link below), and unzip the file.  Then, run the ChemistryAddinforWordBeta2.Setup.msi. It may inform you that you need to install the Visual Studio Tools for Office 3.0.  Simply click Yes to download these tools. This will open the download in your default browser.  Simply click run, or save and then run it when it is downloaded. Now, click next to install the Visual Studio Tools for Office as usual. When this is finished, run the ChemistryAddinforWordBeta2.Setup.msi again.  This time, you can easily install it with the default options. Once it’s finished installing, open Word to try out the Chemistry Add-in.  You will be asked if you want to install this customization, so click Install to enable it. Now you will have a new Chemistry tab in your Word ribbon.  Here’s the ribbon in Word 2010… And here it is in Word 2007.   Using the Chemistry Add-in It’s very easy to insert nice chemistry diagrams and formulas in Word with the Chemistry add-in.  You can quickly insert a premade diagram from the Chemistry Gallery: Or you can insert a formula from file.  Simply click “From File” and choose any Chemical Markup Language (.cml) formatted file to insert the chemical formula. You can also convert any chemical name to it’s chemical form.  Simply select the word, right-click, select “Convert to Chemistry Zone” and then click on its name. Now you can see the chemical form in the sidebar if you click the Chemistry Navigator button, and can choose to insert the diagram into the document.  Some chemicals will automatically convert to the diagram in the document, while others simply link to it in the sidebar.  Either way, you can display exactly what you want. You can also convert a chemical formula directly to it’s chemical diagram.  Here we entered H2O and converted it to Chemistry Zone: This directly converted it to the diagram directly in the document. You can click the Edit button on the top, and from there choose to either edit the 2D model of the chemical, or edit the labels. When you click Edit Labels, you may be asked which form you wish to display.  Here’s the options for potassium permanganate: You can then edit the names and formulas, and add or remove any you wish. If you choose to edit the chemical in 2D, you can even edit the individual atoms and change the chemical you’re diagramming.  This 2D editor has a lot of options, so you can get your chemical diagram to look just like you want. And, if you need any help or want to learn more about the Chemistry add-in and its features, simply click the help button in the Chemistry Ribbon.  This will open a Word document containing examples and explanations which can be helpful in mastering all the features of this add-in. All of this works perfectly, whether you’re running it in Word 2007 or 2010, 32 or 64 bit editions. Conclusion Whether you’re using chemistry formulas everyday or simply want to investigate a chemical makeup occasionally, this is a great way to do it with tools you already have on your computer.  It will also help make homework a bit easier if you’re struggling with it in high school or college. Links Download the Chemistry Add-in for Word Introducing Chemistry Add-in for Word – MSDN blogs Chemistry Markup Language – Wikipedia Similar Articles Productive Geek Tips Geek Reviews: Using Dia as a Free Replacement for Microsoft VisioEasily Summarize A Word 2007 DocumentCreate a Hyperlink in a Word 2007 Flow Chart and Hide Annoying ScreenTipsHow To Create and Publish Blog Posts in Word 2010 & 2007Using Word 2007 as a Blogging Tool TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips Revo Uninstaller Pro Registry Mechanic 9 for Windows PC Tools Internet Security Suite 2010 PCmover Professional Windows 7 Easter Theme YoWindoW, a real time weather screensaver Optimize your computer the Microsoft way Stormpulse provides slick, real time weather data Geek Parents – Did you try Parental Controls in Windows 7? Change DNS servers on the fly with DNS Jumper

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  • How to Avoid Duplicate Key Exception

    - by LifeH2O
    I am using TableAdapter to insert records in table within a loop. foreach(....) { .... .... teamsTableAdapter.Insert(_teamid, _teamname); .... } Where TeamID is the primary key in the table After first run of this loop, Insert throws Duplicate Primary Key found Exception. To handle this, i have done this foreach(....) { .... .... try { _teamsTableAdapter.Insert(_teamid, _teamname); } catch (System.Data.SqlClient.SqlException e) { if (e.Number != 2627) MessageBox.Show(e.Message); } .... .... } But using try catch statement is costly, how to avoid this exception. I am working in VS2010 and INSERT ... ON DUPLICATE KEY UPDATE does not work.

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  • Inserting and Deleting Sub Rows in GridView

    - by Vincent Maverick Durano
    A user in the forums (http://forums.asp.net) is asking how to insert  sub rows in GridView and also add delete functionality for the inserted sub rows. In this post I'm going to demonstrate how to this in ASP.NET WebForms.  The basic idea to achieve this is we just need to insert row data in the DataSource that is being used in GridView since the GridView rows will be generated based on the DataSource data. To make it more clear then let's build up a sample application. To start fire up Visual Studio and create a WebSite or Web Application project and then add a new WebForm. In the WebForm ASPX page add this GridView markup below:   1: <asp:gridview ID="GridView1" runat="server" AutoGenerateColumns="false" onrowdatabound="GridView1_RowDataBound"> 2: <Columns> 3: <asp:BoundField DataField="RowNumber" HeaderText="Row Number" /> 4: <asp:TemplateField HeaderText="Header 1"> 5: <ItemTemplate> 6: <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox> 7: </ItemTemplate> 8: </asp:TemplateField> 9: <asp:TemplateField HeaderText="Header 2"> 10: <ItemTemplate> 11: <asp:TextBox ID="TextBox2" runat="server"></asp:TextBox> 12: </ItemTemplate> 13: </asp:TemplateField> 14: <asp:TemplateField HeaderText="Header 3"> 15: <ItemTemplate> 16: <asp:TextBox ID="TextBox3" runat="server"></asp:TextBox> 17: </ItemTemplate> 18: </asp:TemplateField> 19: <asp:TemplateField HeaderText="Action"> 20: <ItemTemplate> 21: <asp:LinkButton ID="LinkButton1" runat="server" onclick="LinkButton1_Click" Text="Insert"></asp:LinkButton> 22: </ItemTemplate> 23: </asp:TemplateField> 24: </Columns> 25: </asp:gridview>   Then at the code behind source of ASPX page you can add this codes below:   1: private DataTable FillData() { 2:   3: DataTable dt = new DataTable(); 4: DataRow dr = null; 5:   6: //Create DataTable columns 7: dt.Columns.Add(new DataColumn("RowNumber", typeof(string))); 8:   9: //Create Row for each columns 10: dr = dt.NewRow(); 11: dr["RowNumber"] = 1; 12: dt.Rows.Add(dr); 13:   14: dr = dt.NewRow(); 15: dr["RowNumber"] = 2; 16: dt.Rows.Add(dr); 17:   18: dr = dt.NewRow(); 19: dr["RowNumber"] = 3; 20: dt.Rows.Add(dr); 21:   22: dr = dt.NewRow(); 23: dr["RowNumber"] = 4; 24: dt.Rows.Add(dr); 25:   26: dr = dt.NewRow(); 27: dr["RowNumber"] = 5; 28: dt.Rows.Add(dr); 29:   30: //Store the DataTable in ViewState for future reference 31: ViewState["CurrentTable"] = dt; 32:   33: return dt; 34:   35: } 36:   37: private void BindGridView(DataTable dtSource) { 38: GridView1.DataSource = dtSource; 39: GridView1.DataBind(); 40: } 41:   42: private DataRow InsertRow(DataTable dtSource, string value) { 43: DataRow dr = dtSource.NewRow(); 44: dr["RowNumber"] = value; 45: return dr; 46: } 47: //private DataRow DeleteRow(DataTable dtSource, 48:   49: protected void Page_Load(object sender, EventArgs e) { 50: if (!IsPostBack) { 51: BindGridView(FillData()); 52: } 53: } 54:   55: protected void LinkButton1_Click(object sender, EventArgs e) { 56: LinkButton lb = (LinkButton)sender; 57: GridViewRow row = (GridViewRow)lb.NamingContainer; 58: DataTable dtCurrentData = (DataTable)ViewState["CurrentTable"]; 59: if (lb.Text == "Insert") { 60: //Insert new row below the selected row 61: dtCurrentData.Rows.InsertAt(InsertRow(dtCurrentData, row.Cells[0].Text + "-sub"), row.RowIndex + 1); 62:   63: } 64: else { 65: //Delete selected sub row 66: dtCurrentData.Rows.RemoveAt(row.RowIndex); 67: } 68:   69: BindGridView(dtCurrentData); 70: ViewState["CurrentTable"] = dtCurrentData; 71: } 72:   73: protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e) { 74: if (e.Row.RowType == DataControlRowType.DataRow) { 75: if (e.Row.Cells[0].Text.Contains("-sub")) { 76: ((LinkButton)e.Row.FindControl("LinkButton1")).Text = "Delete"; 77: } 78: } 79: }   As you can see the code above is pretty straight forward and self explainatory but just to give you a short explaination the code above is composed of three (3) private methods which are the FillData(), BindGridView and InsertRow(). The FillData() method is a method that returns a DataTable and basically creates a dummy data in the DataTable to be used as the GridView DataSource. You can replace the code in that method if you want to use actual data from database but for the purpose of this example I just fill the DataTable with a dummy data on it. The BindGridVew is a method that handles the actual binding of GridVew. The InsertRow() is a method that returns a DataRow. This method handles the insertion of the sub row. Now in the LinkButton OnClick event, we casted the sender to a LinkButton to determine the specific object that fires up the event and get the row values. We then reference the Data from ViewState to get the current data that is being used in the GridView. If the LinkButton text is "Insert" then we will insert new row to the DataSource ( in this case the DataTable) based on the rowIndex if not then Delete the sub row that was added. Here are some screen shots of the output below: On initial load:   After inserting a sub row:   That's it! I hope someone find this post useful!   Technorati Tags: ASP.NET,C#,GridView

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  • Behaviour of insertion trigger when defining autoincrement in Oracle

    - by Genba
    I have been looking for a way to define an autoincrement data type in Oracle and have found these questions on Stack Overflow: Autoincrement in Oracle Autoincrement Primary key in Oracle database The way to use autoincrement types consists in defining a sequence and a trigger to make insertion transparent, where the insertion trigger looks so: create trigger mytable_trg before insert on mytable for each row when (new.id is null) begin select myseq.nextval into :new.id from dual; end; I have some doubts about the behaviour of this trigger: What does this trigger do when the supplied value of "id" is different from NULL? What does the colon before "new" mean? I want the trigger to insert the new row with the next value of the sequence as ID whatever the supplied value of "new.id" is. I imagine that the WHEN statement makes the trigger to only insert the new row if the supplied ID is NULL (and it will not insert, or will fail, otherwise). Could I just remove the WHEN statement in order for the trigger to always insert using the next value of the sequence?

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  • How can I write query to output this format in SQLite?

    - by GivenPie
    I would like to output in this format: e.EE_id e.FNAME e.LNAME SUPer_id s.FNAME s.LNAME --- --------- -------------- --- ------------- ------------------- 1 Ziqiao Li 2 Charlie Li 1 Ziqiao Li 3 George Pee 2 Charlie Li 4 Jason Dee 2 Charlie Li 5 Petey Wee 2 Charlie Li From this table created : I need to display the Primary key and foreign key in the same results while displaying the foreign key name values for the primary key names. Create table Employees( ee_id integer, fname varchar(20), lname varchar(20), super_id integer, Constraint emp_Pk Primary Key (ee_id), Constraint emp_Fk Foreign Key (super_id) references employees (ee_id) ); INSERT INTO Employees VALUES(1,'Charlie','Li',null); INSERT INTO Employees VALUES(2,'Ziqiao','Lee',1); INSERT INTO Employees VALUES(3,'George','Pee',2); INSERT INTO Employees VALUES(4,'Jason','Dee',2); INSERT INTO Employees VALUES(5,'Petey','Wee',2); Select ee_id, fname, lname, super_id from employees; ee_id fname lname super_id ---------- ---------- ---------- ---------- 1 Charlie Li 2 Ziqiao Lee 1 3 George Pee 2 4 Jason Dee 2 5 Petey Wee 2 Do I need to create a view?

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  • Check For Duplicate Records VS try/catch Unique Key Constraint

    - by Jed
    I have a database table that has a Unique Key constraint defined to avoid duplicate records from occurring. I'm curious if it is bad practice to NOT manually check for duplicate records prior to running an INSERT statement on the table. In other words, should I run a SELECT statement using a WHERE clause that checks for duplicate values of the record that I am about to INSERT. If a record is found, then do not run the INSERT statement, otherwise go ahead and run the INSERT.... OR Just run the INSERT statement and try/catch the exception that may be thrown due to a Unique Key violation. I'm weighing the two perspectives and can't decide which is best- 1. Don't waste a SELECT call to check for duplicates when I can just trap for an exception VS 2. Don't be lazy by implementing ugly try/catch logic VS 3. ???Your thoughts here??? :)

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  • JPA and MySQL transaction isolation level

    - by armandino
    I have a native query that does a batch insert into a MySQL database: String sql = "insert into t1 (a, b) select x, y from t2 where x = 'foo'"; EntityTransaction tx = entityManager.getTransaction(); try { tx.begin(); int rowCount = entityManager.createNativeQuery(sql).executeUpdate(); tx.commit(); return rowCount; } catch(Exception ex) { tx.rollback(); log.error(...); } This query causes a deadlock: while it reads from t2 with insert .. select, another process tries to insert a row into t2. I don't care about the consistency of reads from t2 when doing an insert .. select and want to set the transaction isolation level to READ_UNCOMMITTED. How do I go about setting it in JPA?

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  • std::deque: How do I get an iterator pointing to the element at a specified index?

    - by Ptah- Opener of the Mouth
    I have a std::deque, and I want to insert an element at a specified index (I'm aware that std::list would be better at this). The deque::insert() function takes an iterator to specify the location to insert. Given an index, how can I get an iterator pointing to that location, so that I can pass that iterator to insert()? For example: void insertThing ( deque<Thing> & things, Thing thing, size_t index ) { deque<Thing>::iterator it = /* what do I do here? */ things.insert ( it, thing ); } I'm sure this is a very basic question, and I apologize for it. It's been a long time since I've used the STL, and I don't see anything in std::deque's member list that obviously does what I want. Thanks.

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  • What is the easiest way to find a sql query returns a result or not?

    - by bala3569
    Consider the following sql server query , DECLARE @Table TABLE( Wages FLOAT ) INSERT INTO @Table SELECT 20000 INSERT INTO @Table SELECT 15000 INSERT INTO @Table SELECT 10000 INSERT INTO @Table SELECT 45000 INSERT INTO @Table SELECT 50000 SELECT * FROM ( SELECT *, ROW_NUMBER() OVER(ORDER BY Wages DESC) RowID FROM @Table ) sub WHERE RowID = 3 The result of the query would be 20000 ..... Thats fine as of now i have to find the result of this query, SELECT * FROM ( SELECT *, ROW_NUMBER() OVER(ORDER BY Wages DESC) RowID FROM @Table ) sub WHERE RowID = 6 It will not give any result because there are only 5 rows in the table..... so now my question is What is the easiest way to find a sql query returns a result or not?

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  • MySQL ignores the NOT NULL constraint

    - by Marga Keuvelaar
    I have created a table with NOT NULL constraints on some columns in MySQL. Then in PHP I wrote a script to insert data, with an insert query. When I omit one of the NOT NULL columns in this insert statement I would expect an error message from MySQL, and I would expect my script to fail. Instead, MySQL inserts empty strings in the NOT NULL fields. In other omitted fields the data is NULL, which is fine. Could someone tell me what I did wrong here? I'm using this table: CREATE TABLE IF NOT EXISTS tblCustomers ( cust_id int(11) NOT NULL AUTO_INCREMENT, custname varchar(50) NOT NULL, company varchar(50), phone varchar(50), email varchar(50) NOT NULL, country varchar(50) NOT NULL, ... date_added timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP, PRIMARY KEY (cust_id) ) ; And this insert statement: $sql = "INSERT INTO tblCustomers (custname,company) VALUES ('".$customerName."','".$_POST["CustomerCompany"]."')"; $res = mysqli_query($mysqli, $sql);

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  • IS NULL doesn't work as expected in SQL Server 2000 with no Service Pack on it

    - by user306825
    The following batch executed on different instances of SQL Server 2000 illustrates the problem. select @@version create table a (a int) create table b (b int) insert into a(a) values (1) insert into a(a) values (2) insert into a(a) values (3) insert into b(b) values (1) insert into b(b) values (2) select * from a left outer join (select 1 as test, b from b) as j on j.b = a.a where j.test IS NULL drop table a drop table b Output 1: Microsoft SQL Server 2000 - 8.00.194 (Intel X86) Aug 6 2000 00:57:48 Copyright (c) 1988-2000 Microsoft Corporation Developer Edition on Windows NT 6.1 (Build 7600: ) (1 row(s) affected) (1 row(s) affected) (1 row(s) affected) (1 row(s) affected) (1 row(s) affected) (1 row(s) affected) a test b ----------- ----------- ----------- (0 row(s) affected) Output 2: Microsoft SQL Server 2000 - 8.00.2039 (Intel X86) May 3 2005 23:18:38 Copyright (c) 1988-2003 Microsoft Corporation Developer Edition on Windows NT 5.2 (Build 3790: Service Pack 2) (1 row(s) affected) (1 row(s) affected) (1 row(s) affected) (1 row(s) affected) (1 row(s) affected) (1 row(s) affected) a test b ----------- ----------- ----------- 3 NULL NULL (1 row(s) affected) If someone encounters the same problem - make sure you have the SP installed!

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  • NHibernate parent-childs save redundant sql update executed

    - by Broken Pipe
    I'm trying to save (insert) parent object with a collection of child objects, all objects are new. I prefer to manually specify what to save\update and when so I do not use any cascade saves in mappings and flush sessions by myself. So basically I save this object graph like: session.Save(Parent) foreach (var child in Parent.Childs) { session.Save(child); } session.Flush() I expect this code to insert Parent row, then each child row, however NHibernate executes this SQL: INSERT INTO PARENT.... INSERT INTO CHILD .... UPDATE CHILD SET ParentId=@1 WHERE Id=@2 This update statement is absolutely unnecessary, ParentId was already set correctly in INSERT. How do I get rid of it? Performance is very important for me.

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  • triggers for generating userID based on user's information.

    - by nectar
    I have complaint table 1. tblProfile with columns userId | name | age | address | mobileno | 2. tblUserId with columns userId | role | status now when user fills the form I want to insert one row in tblProfile, before inserting a new row I want to create userId by combining starting letters of name and mobile no and then insert into tblprofile with userId after this I want to insert that UserId into tblUserId table. for this I have to use two triggers one is before insert trigger and another is after insert trigger.but I dont know how to capture user information to create userId and how to pass that Id to second trigger.

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  • Why does MySQL autoincrement increase on failed inserts?

    - by Sorcy
    A co-worker just made me aware of a very strange MySQL behavior. Assuming you have a table with an auto_increment field and another field that is set to unique (e.g. a username-field). When trying to insert a row with a username thats already in the table the insert fails, as expected. Yet the auto_increment value is increased as can be seen when you insert a valid new entry after several failed attempts. For example, when our last entry looks like this... ID: 10 Username: myname ...and we try five new entries with the same username value on our next insert we will have created a new row like so: ID: 16 Username: mynewname While this is not a big problem in itself it seems like a very silly attack vector to kill a table by flooding it with failed insert requests, as the MySQL Reference Manual states: "The behavior of the auto-increment mechanism is not defined if [...] the value becomes bigger than the maximum integer that can be stored in the specified integer type." Is this expected behavior?

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  • IS NULL doesn't work as expected in MSSQL 2000 with no Service Pack on it

    - by user306825
    The following batch executed on different instances of mssql 2000 illustrates the problem. select @@version create table a (a int) create table b (b int) insert into a(a) values (1) insert into a(a) values (2) insert into a(a) values (3) insert into b(b) values (1) insert into b(b) values (2) select * from a left outer join (select 1 as test, b from b) as j on j.b = a.a where j.test IS NULL drop table a drop table b Output 1: Microsoft SQL Server 2000 - 8.00.194 (Intel X86) Aug 6 2000 00:57:48 Copyright (c) 1988-2000 Microsoft Corporation Developer Edition on Windows NT 6.1 (Build 7600: ) (1 row(s) affected) (1 row(s) affected) (1 row(s) affected) (1 row(s) affected) (1 row(s) affected) (1 row(s) affected) a test b (0 row(s) affected) Output 2: Microsoft SQL Server 2000 - 8.00.2039 (Intel X86) May 3 2005 23:18:38 Copyright (c) 1988-2003 Microsoft Corporation Developer Edition on Windows NT 5.2 (Build 3790: Service Pack 2) (1 row(s) affected) (1 row(s) affected) (1 row(s) affected) (1 row(s) affected) (1 row(s) affected) (1 row(s) affected) a test b 3 NULL NULL (1 row(s) affected) If someone encounters the same problem - make sure you have the SP installed!

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  • mysql ignores not null constraint?

    - by Marga Keuvelaar
    I have created a table with NOT NULL constraints on some columns in MySQL. Then in PHP I wrote a script to insert data, with an insert query. When I omit one of the NOT NULL columns in this insert statement I would expect an error message from MySQL, and I would expect my script to fail. Instead, MySQL inserts empty strings in the NOT NULL fields. In other omitted fields the data is NULL, which is fine. Could someone tell me what I did wrong here? I'm using this table: CREATE TABLE IF NOT EXISTS tblCustomers ( cust_id int(11) NOT NULL AUTO_INCREMENT, custname varchar(50) NOT NULL, company varchar(50), phone varchar(50), email varchar(50) NOT NULL, country varchar(50) NOT NULL, ... date_added timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP, PRIMARY KEY (cust_id) ) ; And this insert statement: $sql = "INSERT INTO tblCustomers (custname,company) VALUES ('".$customerName."','".$_POST["CustomerCompany"]."')"; $res = mysqli_query($mysqli, $sql);

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  • Spring Jdbc Template + MySQL = TransientDataAccessResourceException : Invalid Argument Value : Java.

    - by Vanchinathan
    I was using spring jdbc template to insert some data into the database and I was getting this error. Here is my code : JdbcTemplate insert = new JdbcTemplate(dataSource); for(ResultType result : response.getResultSet().getResult()) { Object[] args = new Object[] {result.getAddress(), result.getCity(), result.getState(), result.getPhone(), result.getLatitude(), result.getLongitude(),result.getRating().getAverageRating(), result.getRating().getAverageRating(), result.getRating().getTotalRatings(), result.getRating().getTotalReviews(), result.getRating().getLastReviewDate(), result.getRating().getLastReviewIntro(), result.getDistance(), result.getUrl(), result.getClickUrl(), result.getBusinessUrl(), result.getBusinessClickUrl()}; insert.update("INSERT INTO data.carwashes ( address, city, state, phone, lat, lng, rating, average_rating, total_ratings, total reviews, last_review_date, last_review_intro, distance, url, click_url, business_url, business_click_url, category_id, zipcode_id) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?,96925724,78701)", args); } Quite lengthy code.. but, basically it gets the value from a object and sticks it to a array and passed that array to insert method of jdbc template. Any help will be appreciated.

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  • Find Date From Non Contiguous Ranges

    - by AGoodDisplayName
    I am looking to find an best way to find a date from date ranges that may or may not be contiguous (I am trying to avoid a cursor, or a heavy function if possible). Lets say I have hotel guests that come and go (check in, check out). I want to find the date that a certain guest stayed their 45th night with us. The database we use records the data as so: Create Table #GuestLog( ClientId int, StartDate DateTime, EndDate DateTime) Here is some data Insert Into #GuestLog Values(1, '01/01/2010', '01/10/2010') Insert Into #GuestLog Values(1, '01/16/2010', '01/29/2010') Insert Into #GuestLog Values(1, '02/13/2010', '02/26/2010') Insert Into #GuestLog Values(1, '04/05/2010', '06/01/2010') Insert Into #GuestLog Values(1, '07/01/2010', '07/21/2010') So far I can only think of solutions that involve functions with temp tables and crazy stuff like that, I feel like I'm over thinking it. Thanks ahead of time.

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  • Tsql to find the start and end date(set based)

    - by priyanka.sarkar_2
    I have the below Name Date A 2011-01-01 01:00:00.000 A 2011-02-01 02:00:00.000 A 2011-03-01 03:00:00.000 B 2011-04-01 04:00:00.000 A 2011-05-01 07:00:00.000 The desired output being Name StartDate EndDate ------------------------------------------------------------------- A 2011-01-01 01:00:00.000 2011-04-01 04:00:00.000 B 2011-04-01 04:00:00.000 2011-05-01 07:00:00.000 A 2011-05-01 07:00:00.000 NULL How to achieve the same using TSQL in Set based approach DDL is as under DECLARE @t TABLE(PersonName VARCHAR(32), [Date] DATETIME) INSERT INTO @t VALUES('A', '2011-01-01 01:00:00') INSERT INTO @t VALUES('A', '2011-01-02 02:00:00') INSERT INTO @t VALUES('A', '2011-01-03 03:00:00') INSERT INTO @t VALUES('B', '2011-01-04 04:00:00') INSERT INTO @t VALUES('A', '2011-01-05 07:00:00') Select * from @t

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