Package handling the compilation of queries. Provides compilation of "string-based" queries. Provides handling for different query languages such as JDOQL and JPQL. Compilation of a string-based query goes through two steps.

1. Parse of the string converting each component of the query into a Node tree
2. Compilation of the Node tree into an expression tree

From this tree the evaluation process can be configured to convert it into the native query language for the datastore; this part is handled within each datastore plugin. From this tree an in-memory evaluation can be performed. This is provided in the org.datanucleus.query.evaluator package and subpackage(s).