The following code snippet shows an example of opening more multiple DB2DataReader objects on a connection at the same time: //Open connection to the databaseĭB2Connection conn = new DB2Connection (“database=sample ”) In fact, this new capability can be extended to support the entire DB2 UDB family – although you will need the DB2 Connect product to support this feature with DB2 UDB for z/OS and DB2 UDB for i5/OS databases. This will also enable common language runtime (CLR) stored procedures – supported in the DB2 UDB product since September 2004 – to return multiple result sets too.Ĭoncurrent data reader capability is not just limited to the DB2 UDB product running on Linux, UNIX, or Windows operating systems. Quite simply, this feature delivers the capability for your applications to have multiple DB2DataReader objects open on a connection at the same time when each instance of the DB2DataReader is started from a separate command. Prior to V8.2.2, each database connection could only support one open result set on a connection at any one time. The concurrent data reader support in DB2 UDB enables an application to access more than one result set over the same database connection and query them concurrently. Of course, I will give the usual advice about holding any locks held until a statement is closed, but that is business-as-usual and not specific to using multiple active statements at the same time.Ĭoncurrent Data Readers in DB2 UDB Version 8.2.2 or later However, in the DB2 UDB case, associated overhead seems very limited in my tests. Keep in mind that this capability is not a panacea: there are costs to having multiple statements executing. The CLI, JDBC, and SQLJ interfaces in DB2 UDB, for example, have had this support for years. In fact, enabling this feature in DB2 UDB was as simple as removing the client side restriction that stood in the way of externalizing this support. To enable this support in DB2 UDB, the IBM development teams did not have to address the same limitations that the Microsoft teams apparently faced, so they could deliver this feature quickly in response to customer demand. This implementation was done by adding an abstract layer (session) between the connection and the statement, which may indicate a potential overhead cost to having multiple sessions opened. feature) to enable multiple statements on a single connection. In SQL Server 2005, Microsoft appears to have changed their model (with their M.A.R.S. If you exceeded this restriction, an open cursor would block out all other statements, not just other cursors. SQL Server 2000 has been unable to have more than a single statement open at a time on a connection. Given the nature of SELECT, INSERT, UPDATE, and DELETE statements, it is easier to have multiple cursors open where the application can alternate fetches between two cursors to show they are concurrent. The type of statement is irrelevant (SELECT, INSERT, UPDATE, or DELETE). MARS is actually more than this, but this is the crux of the new feature scheduled for SQL Server 2005.Īll the DB2 UDB family servers have fully supported having multiple statements open per connection for a very long time. Microsoft refers to what I am calling Concurrent Data Readers as Multiple Active Result Sets (MARS). This sounds a lot like Multiple Active Results Sets (MARS) support SQL Server 2005 release… How did DB2 UDB manage to do this so early? In this article, I want to introduce you to this new feature and show you some sample code that you can use to deliver this powerful functionality to your DB2 UDB applications. You can download this product, which came out in April 2005, at. Once you have extracted the relevant jar file to your disk, you need to configure SQL Developer to tell it where this driver resides.Since its Version 8.2.2 release, also known as Fix Pack 9, the IBM DB2 Universal Database product (DB2 UDB) has provided the capability for a concurrent data reader to access more than one result set in the same database connection and query both of those result sets concurrently. Both the Teradata JDBC Driver 12.0 and 13.0 use the jar files terajdbc4.jar and tdgssconfig.jar. Teradata: Use Teradata JDBC Driver 12.0 or above.The jar file is called mysql-connector-java-5.0.4-bin.jar. The binary driver is located within the mysql-connector-java-5.0.4.tar.gz (or. MySQL: MySQL JDBC Driver, version 5.04.The binary driver is located within the. Microsoft SQL Server and Sybase:jTDS driver version 1.2.Microsoft Access:No additional driver is required.IBM DB2: You need the binary driver jar files db2jcc.jar and db2jcc_license_cu.jar.SQL Developer supports the following JDBC drivers. Database vendors offer JDBC drivers as free downloads. JDBC is the Java Database Connectivity standard and it provides a mechanism for Java programs to connect to databases.To access databases using JDBC, you must use a JDBC driver.
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