Examples of org.datanucleus.store.rdbms.sql.DiscriminatorStatementGenerator

org.datanucleus.store.rdbms.sql.DiscriminatorStatementGenerator

Class to generate an SQLStatement for iterating through instances of a particular type (and optionally subclasses). Based around the candidate type having subclasses the candidate has a discriminator column, and so can be used as the way of determining the type of the object. Also allows select of the discriminator column to allow retrieval of the type of the object. Please refer to the specific constructors for the usages. Note that the statement returned by getStatement() has nothing selected, solely providing the basic structure. Column selection should be performed when generating the mapping definition.

Supported options

This generator supports the following "options" :-

restrictDiscriminator : Whether to add a WHERE clause to restrict the discriminator to only valid values (default="true")
allowNulls : whether we allow for null objects (only happens when we have a join table collection.

                Class[] cls = new Class[clsNames.length];
                for (int i=0; i<clsNames.length; i++)
                {
                    cls[i] = clr.classForName(clsNames[i]);
                }
                sqlStmt = new DiscriminatorStatementGenerator(storeMgr, clr, cls, true, null, null).getStatement();
            }
            else
            {
                sqlStmt = new DiscriminatorStatementGenerator(storeMgr, clr,
                    clr.classForName(elementInfo[0].getClassName()), true, null, null).getStatement();
            }
            iterateUsingDiscriminator = true;


            // Select the required fields (of the element class)

Examples of org.datanucleus.store.rdbms.sql.DiscriminatorStatementGenerator

Supported options

Related Classes of org.datanucleus.store.rdbms.sql.DiscriminatorStatementGenerator