Difference between revisions of "EclipseLink/Development/DatabasePlatform/SymfowarePlatform"
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SymfowarePlatform is in the main
SymfowarePlatform is in the main jar file and in the org.eclipse.persistence.core bundle.
Revision as of 14:22, 3 March 2010
This is a subclass of DatabasePlatform that can be used by customers using the Symfoware database.
SymfowarePlatform is included in our automatic database platform detection feature and, as such, should automatically be detected when you login if you are using JPA.
If either you are not using JPA, or automatic detection is not working, it can be configured as follows:
- In JPA set the persistence unit property "eclipselink.target-database" to "Symfoware"
- In other configuration set the DatabasePlatform to org.eclipse.persistence.platform.database.SymfowarePlatform
- This setting is available in sessions.xml and deployment.xml
- This setting is also available through direct API on the session
Automatic Table Generation
The following table shows the default SQL data types and sizes used for table generation.
|Java data type||Symfoware SQL data type|
|SMALLINT default 0|
|java.util.Date||Refer to the specified TemporalType mapping|
|enum(ordinal)||Refer to the java.lang.Integer mapping|
|enum(String)||Refer to the java.lang.String mapping|
SymfowarePlatform inherits the limitations of Symfoware Server and its JDBC driver. For example, note the following restrictions. Refer to the database manual for details.
- Reserved SQL keywords cannot be used as table, column or sequence names. Use a different name, or enclose the name in double quotes. For example:
- The default table name of the TABLE generator is "SEQUENCE", with double quotes, which makes it a legal name.
- Spaces cannot be used in table, column or sequence names.
- The MOD(x, y) function is executed as 'CASE WHEN y = 0 THEN x ELSE (x - y * TRUNC( x / y )) END' on Symfoware database, which gives the same result as the MOD function on Oracle database. Input parameters cannot be used for both its arguments at the same time. In such case, calculate the modulus in Java code first and pass the result to the query instead.
- No more than one input parameter can be used as argument to the LOCATE function.
- The first argument to the SUBSTRING function cannot be an input parameter.
- Input parameters cannot be used as adjacent arguments to the CONCAT function. Concatenate the values in Java code first and pass the result to the query instead.
- Input parameters cannot be used at both sides of an operand at the same time in an SQL statement (e.g. '? * ?'). Perform the operation in Java code first and pass the result to the query instead.
- Input parameters cannot be used as arguments to the COALESCE function when it is used in the select list.
- When an input parameter is used as argument to the UPPER, LOWER or LENGTH functions, it is substituted with its value before the SQL statement is sent to the JDBC driver.
- When input parameters are used as arguments to the TRIM function, they are substituted with their values before the SQL statement is sent to the JDBC driver.
- Identity fields cannot be used. When primary key generation type IDENTITY is specified, a database sequence will be used instead.
- Pessimistic Locking adds 'FOR UPDATE' to the SELECT statement, and cannot be used with queries that use DISTINCT.
- Pessimistic Locking cannot be used with queries that select from multiple tables.
- The LockNoWait option of Pessimistic Locking cannot be used; it is ignored when specified (i.e. only 'FOR UPDATE' is added to the SELECT statement).
- Query timeout cannot be used; the timeout value is silently ignored.
- Bulk update and delete operations that require multiple tables to be accessed cannot be used (e.g. bulk operation on an entity that is part of an inheritance hierarchy, etc.). (See bug 298193). When the tables have only a single primary key column, it might be possible to override the query with a native query without EXISTS:
E.g. JPQL statement: DELETE FROM Employee e WHERE (e.salary > 1000) (where 'salary' is stored in secondary table SALARY) Generated SQL: uses EXISTS with a subquery whose FROM clause includes the same table as the DELETE's (fails on Symfoware) Override with native SQL: DELETE FROM EMPLOYEE WHERE ID = ( SELECT s.EMP_ID FROM SALARY s WHERE s.salary > 1000 )
- Dropping of tables, sequences and procedures while the database connection is still open can fail due to unreleased locks. Shut down the Java process that executed the create operation before performing the drop operation, or have the create operation use an unpooled connection that is closed after use (GlassFish's deploy-time table generation function uses an unpooled connection).
The following restrictions are related to EclipseLink specific functionality (outside of JPA scope):
- The standard deviation (STDDEV) and variance (VARIANCE) functions cannot be used.
- '= NULL' and '<> NULL' cannot be used for null comparisons in the WHERE clause. Use 'IS (NOT) NULL' instead.
- A scrollable cursor policy of CONCUR_UPDATABLE mode cannot be used with queries that select from multiple tables.
- UpdateAll and DeleteAll queries on multi-table objects (see limitation of JPA's bulk update and delete operations).
- Columns and literals of different type may need casting to allow them to be compared or assigned. For example:
'SELECT ... WHERE CAST(PHONE_ORDER_VARCHAR AS INTEGER) BETWEEN 0 AND 1'
SymfowarePlatform is in the main EclipseLink jar file and in the org.eclipse.persistence.core bundle.