string GetOperator(SqlBinaryExpression expression)
{
switch (expression.NodeType)
{
case SqlNodeType.BitwiseAnd:
return "&";
case SqlNodeType.And:
return " AND ";
case SqlNodeType.BitwiseOr:
return "|";
case SqlNodeType.Or:
return " OR ";
case SqlNodeType.LessThan:
return " < ";
case SqlNodeType.LessThanOrEqual:
return " <= ";
case SqlNodeType.GreaterThan:
return " > ";
case SqlNodeType.GreaterThanOrEqual:
return " >= ";
case SqlNodeType.Equal:
return " = ";
case SqlNodeType.NotEqual:
return " <> ";
case SqlNodeType.In:
return " IN ";
case SqlNodeType.Is:
return " IS ";
case SqlNodeType.IsNot:
return " IS NOT ";
default:
throw new ArgumentOutOfRangeException();
}
}
protected override SqlExpression Visit(SqlBinaryExpression expression)
{
switch (expression.NodeType)
{
case SqlNodeType.And:
case SqlNodeType.BitwiseAnd:
case SqlNodeType.Or:
case SqlNodeType.BitwiseOr:
return base.Visit(expression);
}
return expression;
}
protected override SqlExpression Visit(SqlBinaryExpression expression)
{
if (expression.Right.NodeType == SqlNodeType.Constant &&
((SqlConstantExpression) expression.Right).Value == null)
{
switch (expression.NodeType)
{
case SqlNodeType.Equal:
return new SqlBinaryExpression(SqlNodeType.Is, expression.Left, new SqlConstantExpression(typeof(object), null));
case SqlNodeType.NotEqual:
return new SqlBinaryExpression(SqlNodeType.IsNot, expression.Left, new SqlConstantExpression(typeof(object), null));
}
}
return base.Visit(expression);
}
protected override SqlExpression Visit(SqlBinaryExpression expression)
{
sql.Append("(");
switch (expression.NodeType)
{
case SqlNodeType.BitwiseAnd:
case SqlNodeType.And:
case SqlNodeType.BitwiseOr:
case SqlNodeType.Or:
case SqlNodeType.LessThan:
case SqlNodeType.LessThanOrEqual:
case SqlNodeType.GreaterThan:
case SqlNodeType.GreaterThanOrEqual:
case SqlNodeType.Equal:
case SqlNodeType.NotEqual:
case SqlNodeType.In:
case SqlNodeType.Is:
case SqlNodeType.IsNot:
Visit(expression.Left);
sql.Append(GetOperator(expression));
Visit(expression.Right);
break;
case SqlNodeType.LikeStartsWith:
Visit(expression.Left);
sql.Append(" LIKE ");
Visit(expression.Right);
sql.Append(" + '%'");
break;
case SqlNodeType.LikeContains:
Visit(expression.Left);
sql.Append(" LIKE ");
sql.Append("'%' + ");
Visit(expression.Right);
sql.Append(" + '%'");
break;
default:
throw new ArgumentOutOfRangeException();
}
sql.Append(")");
return expression;
}
protected virtual SqlExpression Visit(SqlBinaryExpression expression)
{
return new SqlBinaryExpression(expression.NodeType, Visit(expression.Left), Visit(expression.Right));
}
