Module org.eclipse.persistence.core
Package org.eclipse.persistence.platform.database

Class MaxDBPlatform

  • All Implemented Interfaces:
    Serializable, Cloneable, CorePlatform<ConversionManager>, Platform
    public final class MaxDBPlatform
extends DatabasePlatform
    Database Platform for SAP MaxDB.

    Wiki page

    Usage

    The MaxDB platform is configured in the persistence.xml by the following property:

    <property name="eclipselink.target-database" value="MaxDB"/>

    Forward mapping with EclipseLink assumes that MaxDB is configured for unicode (in version 7.7, this is the default). Unicode mode also needs to be specified in the URL as follows:

    jdbc:sapdb://localhost/E32?unicode=yes

    Tested with:

    • DB: MaxDB, kernel 7.8.01 build 004-123-218-928
    • JDBC driver: MaxDB JDBC Driver, SAP AG, 7.6.06 Build 006-000-009-234 (Make-Version: 7.8.01 Build 003-123-215-703)
    Limitations:
    • The platform class must not be used with XA transactions - see bug 329773.
    • SetQueryTimeout or the hint "jakarta.persistence.query.timeout" do not work on MaxDB - see bug 326503.
    • The hint "jakarta.persistence.lock.timeout" has no effect with a positive value; a value of 0 is translated to NOWAIT.
    • The maximum width of an index is 1024 bytes on MaxDB. This also limits the size of a primary key. Moreover the primary key of join tables must not exceed this limit either. As it is composed of the primary key of the two tables that are joined, the combined width of the PKs of these two tables must not exceed this limit. See bug bug 326968.
    • VARCHAR [UNICODE] columns do not preserve trailing spaces - see bug 327435.
    • VARCHAR BYTE columns do not preserve trailing 0 bytes.
    • The hint "jakarta.persistence.lock.timeout=0" (NOWAIT) has no effect when atempting to pessimistically lock an entity with inheritance type JOINED - see bug 326799.
    • Pessimistic locking with lock scope EXTENDED should be used cautiously in the presence of foreign key constraints - see bug 327472.

    Author:
    Markus KARG (markus at headcrashing.eu), afischbach, agoerler, Sabine Heider (sabine.heider at sap.com), Konstantin Schwed (konstantin.schwed at sap.com)
    See Also:
    Serialized Form

    • Constructor Detail

      • MaxDBPlatform

        public MaxDBPlatform()

    • Method Detail

      • isForUpdateCompatibleWithDistinct

        public boolean isForUpdateCompatibleWithDistinct()
        Description copied from class: DatabasePlatform
        INTERNAL: Indicates whether SELECT DISTINCT ... FOR UPDATE is allowed by the platform (Oracle doesn't allow this).
        Overrides:
        isForUpdateCompatibleWithDistinct in class DatabasePlatform

      • supportsIndividualTableLocking

        public boolean supportsIndividualTableLocking()
        Description copied from class: DatabasePlatform
        INTERNAL: Indicates whether locking clause could be selectively applied only to some tables in a ReadQuery. Example: the following locks the rows in SALARY table, doesn't lock the rows in EMPLOYEE table: on Oracle platform (method returns true): SELECT t0.EMP_ID..., t1.SALARY FROM EMPLOYEE t0, SALARY t1 WHERE ... FOR UPDATE t1.SALARY on SQLServer platform (method returns true): SELECT t0.EMP_ID..., t1.SALARY FROM EMPLOYEE t0, SALARY t1 WITH (UPDLOCK) WHERE ...
        Overrides:
        supportsIndividualTableLocking in class DatabasePlatform

      • shouldOptimizeDataConversion

        public boolean shouldOptimizeDataConversion()
        Description copied from class: DatabasePlatform
        Return if our driver level data conversion optimization is enabled. This can be disabled as some drivers perform data conversion themselves incorrectly.
        Overrides:
        shouldOptimizeDataConversion in class DatabasePlatform

      • buildSelectQueryForSequenceObject

        public ValueReadQuery buildSelectQueryForSequenceObject​(String sequenceName,
                                                        Integer size)
        Description copied from class: DatasourcePlatform
        INTERNAL: Returns query used to read value generated by sequence object (like Oracle sequence). In case the other version of this method (taking no parameters) returns null, this method is called every time sequence object NativeSequence reads. If the platform supportsSequenceObjects then (at least) one of buildSelectQueryForSequenceObject methods should return non-null query.
        Overrides:
        buildSelectQueryForSequenceObject in class DatasourcePlatform

      • getCreateTempTableSqlPrefix

        protected String getCreateTempTableSqlPrefix()
        Description copied from class: DatabasePlatform
        INTERNAL: Override this method if the platform supports temporary tables. This should contain the beginning of sql string for creating temporary table - the sql statement name, for instance: "CREATE GLOBAL TEMPORARY TABLE ". Don't forget to end it with a space.
        Overrides:
        getCreateTempTableSqlPrefix in class DatabasePlatform

      • getMaxFieldNameSize

        public int getMaxFieldNameSize()
        Description copied from class: DatabasePlatform
        INTERNAL: returns the maximum number of characters that can be used in a field name on this platform.
        Overrides:
        getMaxFieldNameSize in class DatabasePlatform

      • supportsLocalTempTables

        public boolean supportsLocalTempTables()
        Description copied from class: DatabasePlatform
        INTERNAL: Indicates whether the platform supports local temporary tables. "Local" means that several threads may create temporary tables with the same name. Local temporary table is created in the beginning of UpdateAllQuery execution and dropped in the end of it. Override this method if the platform supports local temporary tables.
        Overrides:
        supportsLocalTempTables in class DatabasePlatform

      • shouldAlwaysUseTempStorageForModifyAll

        public boolean shouldAlwaysUseTempStorageForModifyAll()
        Description copied from class: DatabasePlatform
        INTERNAL: That method affects UpdateAllQuery and DeleteAllQuery execution. In case it returns false modify all queries would attempt to proceed without using temporary storage if it is possible. In case it returns true modify all queries would use temporary storage unless each modify statement doesn't reference any other tables. May need to override this method if the platform can't handle the sql generated for modify all queries without using temporary storage.
        Overrides:
        shouldAlwaysUseTempStorageForModifyAll in class DatabasePlatform

      • supportsSequenceObjects

        public boolean supportsSequenceObjects()
        Description copied from class: DatasourcePlatform
        INTERNAL: Indicates whether the platform supports sequence objects. This method is to be used *ONLY* by sequencing classes
        Overrides:
        supportsSequenceObjects in class DatasourcePlatform