static void AppendLimitCondition(DbSqlQueryExpression sqlQuery, int limitCount)
{
DbLessThanExpression lessThanExp = DbExpression.LessThan(OracleSemantics.DbMemberExpression_ROWNUM, DbExpression.Constant(limitCount + 1));
DbExpression condition = lessThanExp;
if (sqlQuery.Condition != null)
{
condition = DbExpression.And(sqlQuery.Condition, condition);
}
sqlQuery.Condition = condition;
}
protected override Expression VisitBinary(BinaryExpression node)
{
var expression = base.VisitBinary(node) as BinaryExpression;
DbExpression dbExpression;
// Need special handling for comparisons against the null constant. If we don't translate these
// using an "IsNull" expression, EF will convert it literally as "= null" which doesn't work in SQL Server.
if (IsNullConstantExpression(expression.Right))
{
dbExpression = MapNullComparison(expression.Left, expression.NodeType);
}
else if (IsNullConstantExpression(expression.Left))
{
dbExpression = MapNullComparison(expression.Right, expression.NodeType);
}
else
{
DbExpression leftExpression = GetDbExpressionForExpression(expression.Left);
DbExpression rightExpression = GetDbExpressionForExpression(expression.Right);
switch (expression.NodeType)
{
case ExpressionType.Equal:
// DbPropertyExpression = class property that has been mapped to a database column
// DbParameterReferenceExpression = lambda parameter
if (IsNullableExpressionOfType <DbPropertyExpression>(leftExpression) && IsNullableExpressionOfType <DbParameterReferenceExpression>(rightExpression))
{
dbExpression = CreateEqualComparisonOfNullablePropToNullableParam(leftExpression, rightExpression);
}
else if (IsNullableExpressionOfType <DbPropertyExpression>(rightExpression) && IsNullableExpressionOfType <DbParameterReferenceExpression>(leftExpression))
{
dbExpression = CreateEqualComparisonOfNullablePropToNullableParam(rightExpression, leftExpression);
}
else
{
dbExpression = leftExpression.Equal(rightExpression);
}
break;
case ExpressionType.NotEqual:
dbExpression = leftExpression.NotEqual(rightExpression);
break;
case ExpressionType.GreaterThan:
dbExpression = leftExpression.GreaterThan(rightExpression);
break;
case ExpressionType.GreaterThanOrEqual:
dbExpression = leftExpression.GreaterThanOrEqual(rightExpression);
break;
case ExpressionType.LessThan:
dbExpression = leftExpression.LessThan(rightExpression);
break;
case ExpressionType.LessThanOrEqual:
dbExpression = leftExpression.LessThanOrEqual(rightExpression);
break;
case ExpressionType.AndAlso:
dbExpression = leftExpression.And(rightExpression);
break;
case ExpressionType.OrElse:
dbExpression = leftExpression.Or(rightExpression);
break;
default:
throw new NotImplementedException(string.Format("Unhandled NodeType of {0} in LambdaToDbExpressionVisitor.VisitBinary", expression.NodeType));
}
}
MapExpressionToDbExpression(expression, dbExpression);
return(expression);
}