/// <summary>
/// Builds the execute command.
/// </summary>
/// <param name="command">The command.</param>
/// <returns></returns>
protected virtual Expression BuildExecuteCommand(CommandExpression command)
{
// parameterize query
var expression = this.Parameterize(command);
string commandText = this.linguist.Format(expression);
ReadOnlyCollection <NamedValueExpression> namedValues = NamedValueGatherer.Gather(expression);
QueryCommand qc = new QueryCommand(commandText, namedValues.Select(v => new QueryParameter(v.Name, v.Type)));
Expression[] values = namedValues.Select(v => Expression.Convert(this.Visit(v.Value), typeof(object))).ToArray();
ProjectionExpression projection = ProjectionFinder.FindProjection(expression);
if (projection != null)
{
return(this.ExecuteProjection(projection, false, qc, values));
}
Expression plan = Expression.Call(this.executor, "ExecuteCommand", null,
Expression.Constant(qc),
Expression.NewArrayInit(typeof(object), values)
);
return(plan);
}
/// <summary>
/// Finds the projection.
/// </summary>
/// <param name="expression">The expression.</param>
/// <returns></returns>
internal static ProjectionExpression FindProjection(Expression expression)
{
var finder = new ProjectionFinder();
finder.Visit(expression);
return(finder.found);
}
/// <summary>
/// Builds the execute batch.
/// </summary>
/// <param name="batch">The batch.</param>
/// <returns></returns>
protected virtual Expression BuildExecuteBatch(BatchExpression batch)
{
// parameterize query
Expression operation = this.Parameterize(batch.Operation.Body);
string commandText = this.linguist.Format(operation);
var namedValues = NamedValueGatherer.Gather(operation);
QueryCommand command = new QueryCommand(commandText, namedValues.Select(v => new QueryParameter(v.Name, v.Type)));
Expression[] values = namedValues.Select(v => Expression.Convert(this.Visit(v.Value), typeof(object))).ToArray();
Expression paramSets = Expression.Call(typeof(Enumerable), "Select", new Type[] { batch.Operation.Parameters[1].Type, typeof(object[]) }, batch.Input, Expression.Lambda(Expression.NewArrayInit(typeof(object), values), new[] { batch.Operation.Parameters[1] }));
Expression plan = null;
ProjectionExpression projection = ProjectionFinder.FindProjection(operation);
if (projection != null)
{
var saveScope = this.scope;
ParameterExpression reader = Expression.Parameter(typeof(FieldReader), "r" + nReaders++);
this.scope = new Scope(this.scope, reader, projection.Select.Alias, projection.Select.Columns);
LambdaExpression projector = Expression.Lambda(this.Visit(projection.Projector), reader);
this.scope = saveScope;
var entity = EntityFinder.Find(projection.Projector);
command = new QueryCommand(command.CommandText, command.Parameters);
plan = Expression.Call(this.executor, "ExecuteBatch", new Type[] { projector.Body.Type },
Expression.Constant(command),
paramSets,
projector,
Expression.Constant(entity, typeof(MappingEntity)),
batch.BatchSize,
batch.Stream
);
}
else
{
plan = Expression.Call(this.executor, "ExecuteBatch", null, Expression.Constant(command), paramSets, batch.BatchSize, batch.Stream);
}
return(plan);
}
