protected override Expression VisitLike(QueryTranslatorContext context, LikeExpression expression)
{
// Is the left side a collection?
if (expression.Left is CollectionExpression collection)
{
// Build the collection accessor parameter.
var parameter = collection.Accept(this, context);
// Build the predicate expression.
context.PushParameter(collection.ItemType);
var predicate = Expression.Lambda(
new LikeExpression(
collection.ItemAccessor,
expression.Right).Accept(this, context),
context.Parameter);
context.PopParameter();
// We need to use an Enumerable.Any together with the LIKE predicate.
return(Expression.Call(typeof(Enumerable), "Any", new Type[] { collection.ItemType }, parameter, predicate));
}
var left = expression.Left.Accept(this, context);
var right = expression.Right.Accept(this, context);
return(Expression.Call(
null, typeof(DbFunctionsExtensions).GetMethod("Like", new[] { typeof(DbFunctions), typeof(string), typeof(string) }),
Expression.Constant(EF.Functions), left, right));
}
protected override Expression VisitRelation(QueryTranslatorContext context, RelationalExpression expression)
{
// Is the left side a collection?
if (expression.Left is CollectionExpression collection)
{
// Build the collection accessor parameter.
var parameter = collection.Accept(this, context);
// Build the predicate expression.
context.PushParameter(collection.ItemType);
var predicate = Expression.Lambda(
new RelationalExpression(
collection.ItemAccessor,
expression.Right,
expression.Operator).Accept(this, context),
context.Parameter);
context.PopParameter();
// Combine them into an Enumerable.Any or Enumerable.All call.
var method = expression.Operator == RelationalOperator.NotEqualTo ? "All" : "Any";
return(Expression.Call(typeof(Enumerable), method, new Type[] { collection.ItemType }, parameter, predicate));
}
var left = expression.Left.Accept(this, context);
var right = expression.Right.Accept(this, context);
switch (expression.Operator)
{
case RelationalOperator.EqualTo:
return(Expression.Equal(left, right));
case RelationalOperator.NotEqualTo:
return(Expression.NotEqual(left, right));
case RelationalOperator.GreaterThan:
return(Expression.GreaterThan(left, right));
case RelationalOperator.GreaterThanOrEqualTo:
return(Expression.GreaterThanOrEqual(left, right));
case RelationalOperator.LessThan:
return(Expression.LessThan(left, right));
case RelationalOperator.LessThanOrEqualTo:
return(Expression.LessThanOrEqual(left, right));
}
throw new InvalidOperationException($"Unknown operator '{expression.Operator}'.");
}