예제 #1
0
        public static Expression Find(Expression expression)
        {
            RootQueryableFinder finder = new RootQueryableFinder();

            finder.Visit(expression);
            return(finder.root);
        }
예제 #2
0
 internal void Compile(params object[] args)
 {
     if (this.fnQuery == null)
     {
         // first identify the query provider being used
         Expression         body = this.query.Body;
         ConstantExpression root = RootQueryableFinder.Find(body) as ConstantExpression;
         if (root == null && args != null && args.Length > 0)
         {
             Expression replaced = ExpressionReplacer.ReplaceAll(
                 body,
                 this.query.Parameters.ToArray(),
                 args.Select((a, i) => Expression.Constant(a, this.query.Parameters[i].Type)).ToArray()
                 );
             body = PartialEvaluator.Eval(replaced);
             root = RootQueryableFinder.Find(body) as ConstantExpression;
         }
         if (root == null)
         {
             throw new InvalidOperationException("Could not find query provider");
         }
         // ask the query provider to compile the query by 'executing' the lambda expression
         IQueryProvider provider = ((IQueryable)root.Value).Provider;
         Delegate       result   = (Delegate)provider.Execute(this.query);
         System.Threading.Interlocked.CompareExchange(ref this.fnQuery, result, null);
     }
 }
예제 #3
0
        /// <summary>
        /// Convert the query expression into an execution plan
        /// </summary>
        /// <param name="expression"></param>
        /// <returns></returns>
        protected virtual Expression GetExecutionPlan(Expression expression)
        {
            // strip off lambda for now
            LambdaExpression lambda = expression as LambdaExpression;

            if (lambda != null)
            {
                expression = lambda.Body;
            }

            // translate query into client and server parts
            ProjectionExpression projection = Translate(expression);

            Expression rootQueryable = RootQueryableFinder.Find(expression);
            Expression provider      = Expression.Convert(
                Expression.Property(rootQueryable, typeof(IQueryable).GetProperty("Provider")),
                typeof(DbQueryProvider)
                );

            return(policy.BuildExecutionPlan(projection, provider));
        }