B.4. Sybase

Example B.10. Sybase Datasource

<?xml version="1.0" encoding="UTF-8"?>

<datasources>
  <local-tx-datasource>
    <jndi-name>jdbc/SybaseDB</jndi-name>
    <!-- Sybase jConnect URL for the database. 
	 NOTE: The hostname and port are made up values. The optional
	 database name is provided, as well as some additinal Driver
	 parameters.
    -->
    <connection-url>jdbc:sybase:Tds:host.at.some.domain:5000/db_name?JCONNECT_VERSION=6</connection-url>
    <driver-class>com.sybase.jdbc2.jdbc.SybDataSource</driver-class>
    <user-name>x</user-name>
    <password>y</password>
    <exception-sorter-class-name>org.jboss.resource.adapter.jdbc.vendor.SybaseExceptionSorter</exception-sorter-class-name>
    <!-- sql to call when connection is created
	 <new-connection-sql>some arbitrary sql</new-connection-sql>
    -->

    <!-- sql to call on an existing pooled connection when it is obtained from pool 
	 <check-valid-connection-sql>some arbitrary sql</check-valid-connection-sql>
    -->

    <!-- corresponding type-mapping in the standardjbosscmp-jdbc.xml (optional) -->
    <metadata>
      <type-mapping>Sybase</type-mapping>
    </metadata>
  </local-tx-datasource>

</datasources>
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B.4.1. Sybase Limitations

Sybase has some configuration anomalies, which you should be aware of.
DDL statements in transactions
Hibernate, which is an integral part of the Enterprise Platform, allows the SQL Dialect to decide whether or not the database supports DDL statements within a transaction. Sybase does not override this. the default is to query the JDBC metadata to see whether DDL is allowed within transactions. However, Sybase does not correct report whether it is set up to use this option.
Sybase recommends against using DDL statements in transactions, because of locking issues. Review the Sybase documentation for how to enable or disable the ddl in tran option.
Sybase does not throw an exception if a value overflows the constraints of the underlying column.
Sybase ASE does not throw an exception when Parameterized Sql is in use. jconn3.jar uses Parameterized Sql for insertion by default, so no exception is thrown if a value overflows the constraints of the underlying column. Since no exception is thrown, Hibernate cannot tell that the insert failed. By using Dynamic Prepare instead of Parameterized SQL, ASE throws an exception. Hibernate can catch this exception and act accordingly.
For that reason, set the Dynamic prepare parameter to true in Hibernate's configuration file. 
<property name="connection.url">jdbc:sybase:Tds:aurum:1503/masterDb?DYNAMIC_PREPARE=true</property>
jconn4.jar uses Dynamic Prepare by default.
SchemaExport cannot create stored procedures in chained transaction mode
On Sybase, SchemaExport cannot be used to create stored procedures while in while in chained transaction mode. The workaround for this case is to add the following code immediately after the definition of the new stored procedure: 
<database-object>
  <create>
    sp_procxmode paramHandling, 'chained'
  </create>
  <drop/>
</database-object>