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Core Java™ Data Objects by Heiko Bobzin, Michael Vorburger, Keiron McCammon, Sameer Tyagi

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6.4. JDOQL

The filter is essentially a string passed to the query facility that is used by the query facility to refine the results returned. The syntax for the filter is specified using JDOQL or the JDO query language. This begs the question: Why use a new syntax? Why not use Structured Query Language (SQL) that is standard to all relational databases? One of the goals of JDO is to isolate the developer from the specifics of the underlying datastore. This means that the query language must be vendor- and implementation-agnostic. The vendor is free to choose SQL, Object Query Language (OQL), or whatever other query language the underlying data-store supports. To quote the specifications, the primary design goals for the query language were:

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