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Package org.datanucleus.store.rdbms.query

Package providing the querying mechanism for DataNucleus for RDBMS datastores.

See: Description

Package org.datanucleus.store.rdbms.query Description

Package providing the querying mechanism for DataNucleus for RDBMS datastores.

Query Generation

Queries are supported on RDBMS datastore using JDOQL, JPQL, SQL, or alternatively StoredProcedures. JDOQL queries are converted into SQL using a query compilation process, firstly compiling generically, and then converting the generic compilation into SQL using
QueryToSQLMapper
. JPQL queries are converted into SQL using a query compilation process, firstly compiling generically, and then converting the generic compilation into SQL using
QueryToSQLMapper
.

Query Result Processing

A query is executed and returns a JDBC ResultSet. The ResultSet is then converted into the requisite result format using either of
PersistentClassROF
,
ResultClassROF
or
ResultMetaDataROF
. These "result object factories" convert each row of the ResultSet into the required object(s). Where part of the result is a persistable object, it makes use of ResultSetGetter to populate the fields of the persistable object.
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