/// <summary>
/// Provides policy specific query translations. This is where choices about inclusion of related objects and how
/// heirarchies are materialized affect the definition of the queries.
/// </summary>
/// <param name="expression"></param>
/// <returns></returns>
public virtual Expression Translate(MetaMapping mapping, Expression expression)
{
// add included relationships to client projection
expression = RelationshipIncluder.Include(mapping, this, expression);
expression = UnusedColumnRemover.Remove(expression);
expression = RedundantColumnRemover.Remove(expression);
expression = RedundantSubqueryRemover.Remove(expression);
expression = RedundantJoinRemover.Remove(expression);
// convert any singleton (1:1 or n:1) projections into server-side joins (cardinality is preserved)
expression = SingletonProjectionRewriter.Rewrite(mapping.Language, expression);
expression = UnusedColumnRemover.Remove(expression);
expression = RedundantColumnRemover.Remove(expression);
expression = RedundantSubqueryRemover.Remove(expression);
expression = RedundantJoinRemover.Remove(expression);
// convert projections into client-side joins
expression = ClientJoinedProjectionRewriter.Rewrite(mapping.Language, expression);
expression = UnusedColumnRemover.Remove(expression);
expression = RedundantColumnRemover.Remove(expression);
expression = RedundantSubqueryRemover.Remove(expression);
expression = RedundantJoinRemover.Remove(expression);
return expression;
}
private QueryBinder(MetaMapping mapping, Expression root)
{
this.mapping = mapping;
this.map = new Dictionary<ParameterExpression, Expression>();
this.groupByMap = new Dictionary<Expression, GroupByInfo>();
this.root = root;
}
public static Expression Bind(MetaMapping mapping, Expression expression)
{
return new RelationshipBinder(mapping).Visit(expression);
}
private RelationshipBinder(MetaMapping mapping)
{
this.mapping = mapping;
}
/// <summary>
/// Converts a query into an execution plan. The plan is an function that executes the query and builds the
/// resulting objects.
/// </summary>
/// <param name="projection"></param>
/// <param name="provider"></param>
/// <returns></returns>
public virtual Expression BuildExecutionPlan(MetaMapping mapping, Expression query, Expression provider)
{
return ExecutionBuilder.Build(mapping, this, query, provider);
}
public static Expression Include(MetaMapping mapping, QueryPolicy policy, Expression expression)
{
return new RelationshipIncluder(mapping, policy).Visit(expression);
}
private RelationshipIncluder(MetaMapping mapping, QueryPolicy policy)
{
this.mapping = mapping;
this.policy = policy;
}
public static Expression Bind(MetaMapping mapping, Expression expression)
{
return new QueryBinder(mapping, expression).Visit(expression);
}