protected virtual Expression VisitBatch(BatchExpression batch)
{
LambdaExpression operation = (LambdaExpression)Visit(batch.Operation);
Expression batchSize = Visit(batch.Size);
Expression stream = Visit(batch.Stream);
return(UpdateBatch(batch, batch.Input, operation, batchSize, stream));
}
protected BatchExpression UpdateBatch(BatchExpression batch, Expression input,
LambdaExpression operation, Expression batchSize, Expression stream)
{
if (input != batch.Input || operation != batch.Operation ||
batchSize != batch.Size || stream != batch.Stream)
{
return(new BatchExpression(input, operation, batchSize, stream));
}
return(batch);
}
protected virtual Expression BuildExecuteBatch(BatchExpression batch)
{
// parameterize query
Expression operation = this.Parameterize(batch.Operation.Body);
string commandText = this.mapping.Language.Format(operation);
var namedValues = NamedValueGatherer.Gather(operation);
QueryCommand command = new QueryCommand(commandText, namedValues.Select(v => new QueryParameter(v.Name, v.Type, v.DbType)), null);
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;
DbProjectionExpression projection = ProjectionFinder.FindProjection(operation);
if (projection != null)
{
var saveScope = this.scope;
ParameterExpression reader = Expression.Parameter(typeof(IDataReader), "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 columns = ColumnGatherer.Gather(projection.Projector);
command = new QueryCommand(command.CommandText, command.Parameters, columns);
plan = Expression.Call(this.provider, "ExecuteBatch", new Type[] { projector.Body.Type },
Expression.Constant(command),
paramSets,
projector,
batch.Size,
batch.Stream
);
}
else
{
plan = Expression.Call(this.provider, "ExecuteBatch", null,
Expression.Constant(command),
paramSets,
batch.Size,
batch.Stream
);
}
return(plan);
}
protected override Expression VisitBatch(BatchExpression batch)
{
if (this.mapping.Language.AllowsMultipleCommands || !IsMultipleCommands(batch.Operation.Body as DbStatementExpression))
{
return(this.BuildExecuteBatch(batch));
}
else
{
var source = this.Visit(batch.Input);
var op = this.Visit(batch.Operation.Body);
var fn = Expression.Lambda(op, batch.Operation.Parameters[1]);
return(Expression.Call(this.GetType(), "Batch", new Type[] { source.Type.GetSequenceElementType(),
batch.Operation.Body.Type }, source, fn, batch.Stream));
}
}
protected BatchExpression UpdateBatch(BatchExpression batch, Expression input,
LambdaExpression operation, Expression batchSize, Expression stream)
{
if (input != batch.Input || operation != batch.Operation ||
batchSize != batch.Size || stream != batch.Stream)
return new BatchExpression(input, operation, batchSize, stream);
return batch;
}
protected virtual Expression VisitBatch(BatchExpression batch)
{
LambdaExpression operation = (LambdaExpression)Visit(batch.Operation);
Expression batchSize = Visit(batch.Size);
Expression stream = Visit(batch.Stream);
return UpdateBatch(batch, batch.Input, operation, batchSize, stream);
}
protected virtual bool CompareBatch(BatchExpression x, BatchExpression y)
{
return(Compare(x.Input, y.Input) && Compare(x.Operation, y.Operation) &&
Compare(x.Size, y.Size) && Compare(x.Stream, y.Stream));
}
protected virtual bool CompareBatch(BatchExpression x, BatchExpression y)
{
return Compare(x.Input, y.Input) && Compare(x.Operation, y.Operation)
&& Compare(x.Size, y.Size) && Compare(x.Stream, y.Stream);
}
