protected virtual Expression VisitCommand(CommandExpression command)
{
switch ((DbExpressionType)command.NodeType)
{
case DbExpressionType.Insert:
return(VisitInsert((InsertCommand)command));
case DbExpressionType.Update:
return(VisitUpdate((UpdateCommand)command));
case DbExpressionType.Delete:
return(VisitDelete((DeleteCommand)command));
case DbExpressionType.If:
return(VisitIf((IFCommand)command));
case DbExpressionType.Block:
return(VisitBlock((BlockCommand)command));
case DbExpressionType.Declaration:
return(VisitDeclaration((DeclarationCommand)command));
default:
return(VisitUnknown(command));
}
}
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, v.QueryType)));
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);
}
protected override Expression VisitCommand(CommandExpression command)
{
if (this.linguist.Language.AllowsMultipleCommands || !IsMultipleCommands(command))
{
return(this.BuildExecuteCommand(command));
}
else
{
return(base.VisitCommand(command));
}
}
protected virtual bool IsMultipleCommands(CommandExpression command)
{
if (command == null)
{
return(false);
}
switch ((DbExpressionType)command.NodeType)
{
case DbExpressionType.Insert:
case DbExpressionType.Delete:
case DbExpressionType.Update:
return(false);
default:
return(true);
}
}
protected override Expression VisitCommand(CommandExpression command)
{
this.isTopLevel = true;
return(base.VisitCommand(command));
}
protected virtual Expression VisitCommand(CommandExpression command)
{
this.Write(this.FormatQuery(command));
return(command);
}