Cayenne User Documentation
Queries Stored in DataMap

To facilitate reuse of queries users can assign symbolic names to them and store such named queries in a DataMap. Normally this is done by creating a query in CayenneModeler. Storing queries in a DataMap reduces the amount of code and speeds up query creation process.

This example shows how to get a shared instance of a stored query, and use it as a template for customized query.

    DataContext context = ... // assume this exists

    // 1. lookup prototype

    // note a cast to SelectQuery... Generally DataMap can store any type of queries
    SelectQuery prototype = (SelectQuery) context.getEntityResolver().lookupQuery("MySelect");

    // 2. customize query
    Map params = new HashMap();
    params.put("aname", "Monet");
    SelectQuery query = prototype.queryWithParameters(params);

    // 3. execute query
    List objects = context.performQuery(query);

DataContext supports running a named query with preset parameters directly:

    DataContext context = ... // assume this exists

    // "false" indicates that a cached result should be used if available
    List objects = context.performQuery("MySelect", false);

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