public TransformVisitor(ITypeConverter converter)
{
this.converter = converter;
this.edmTypeConverter = new EdmTypeConverter(converter);
this.queryMethodExpressionBuilder = new LinqMethodExpressionBuilder();
this.currentVariables = new VariableCollection();
this.parameters = new Dictionary <string, Tuple <TypeUsage, int> >();
this.functionMapper = new CanonicalFunctionMapper(converter);
this.methodProvider = new Effort.Internal.DbManagement.DbMethodProvider();
}
public static Expression GetEnumeratorExpression(
DbExpression predicate,
DbModificationCommandTree commandTree,
DbContainer container,
out ITable table)
{
TransformVisitor visitor = new TransformVisitor(container.TypeConverter);
visitor.TableProvider = container;
// Get the source expression
ConstantExpression source =
visitor.Visit(commandTree.Target.Expression) as ConstantExpression;
// This should be a constant expression
if (source == null)
{
throw new InvalidOperationException();
}
table = source.Value as ITable;
// Get the the type of the elements of the table
Type elementType = TypeHelper.GetElementType(source.Type);
// Create context
ParameterExpression context = Expression.Parameter(elementType, "context");
using (visitor.CreateVariable(context, commandTree.Target.VariableName))
{
// Create the predicate expression
LambdaExpression predicateExpression =
Expression.Lambda(
visitor.Visit(predicate),
context);
// Create Where expression
LinqMethodExpressionBuilder queryMethodBuilder =
new LinqMethodExpressionBuilder();
return queryMethodBuilder.Where(source, predicateExpression);
}
}
