Querybuilder Joins

Overview

Runway’s Querybuilder technology is capable of joining across many different tables, using many different join types.

Left Joins

The following is an example of Left Join chaining using Runway’s Querybuilder.

    SynonymRelationshipQuery relationshipQuery = new SynonymRelationshipQuery(vQuery);
    SynonymQuery synonymQuery = new SynonymQuery(vQuery);
    SynonymDisplayLabelQuery labelQuery = new SynonymDisplayLabelQuery(vQuery);

    vQuery.WHERE(new LeftJoinEq(geQuery.getOid(), relationshipQuery.parentOid()));
    vQuery.AND(new LeftJoinEq(relationshipQuery.childOid(), synonymQuery.getOid()));
    vQuery.AND(new LeftJoinEq(synonymQuery.getDisplayLabel(), labelQuery.getOid()));

This particular example was pulled from SynonymRestriction.java in the GeoRegistry server project. This example joins a GeoEntity table with it’s associated Synonym, and then joins in the Synonym’s Display label.

When using left joins, ordering is extremely important. Here is an example of correct joining ordering:

    A join B
    B join C
    C join D