Example #1
0
        private void CorrectSkip(SelectQuery selectQuery)
        {
            ((ISqlExpressionWalkable)selectQuery).Walk(new WalkOptions(), e =>
            {
                if (e is SelectQuery q && q.Select.SkipValue != null && SqlProviderFlags.GetIsSkipSupportedFlag(q) && q.OrderBy.IsEmpty)
                {
                    if (q.Select.Columns.Count == 0)
                    {
                        var source = q.Select.From.Tables[0].Source;
                        var keys   = source.GetKeys(true);

                        foreach (var key in keys)
                        {
                            q.Select.AddNew(key);
                        }
                    }

                    for (var i = 0; i < q.Select.Columns.Count; i++)
                    {
                        q.OrderBy.ExprAsc(new SqlValue(i + 1));
                    }

                    if (q.OrderBy.IsEmpty)
                    {
                        throw new LinqToDBException("Order by required for Skip operation.");
                    }
                }
                return(e);
            }
Example #2
0
        protected void CorrectRootSkip(SelectQuery selectQuery)
        {
            if (selectQuery != null && selectQuery.Select.SkipValue != null && SqlProviderFlags.GetIsSkipSupportedFlag(selectQuery) && selectQuery.OrderBy.IsEmpty)
            {
                if (selectQuery.Select.Columns.Count == 0)
                {
                    var source = selectQuery.Select.From.Tables[0].Source;
                    var keys   = source.GetKeys(true);

                    foreach (var key in keys)
                    {
                        selectQuery.Select.AddNew(key);
                    }
                }

                for (var i = 0; i < selectQuery.Select.Columns.Count; i++)
                {
                    selectQuery.OrderBy.ExprAsc(new SqlValue(i + 1));
                }

                if (selectQuery.OrderBy.IsEmpty)
                {
                    throw new LinqToDBException("Order by required for Skip operation.");
                }
            }
        }
Example #3
0
        public override SqlStatement TransformStatement(SqlStatement statement)
        {
            statement = SeparateDistinctFromPagination(statement, q => q.Select.SkipValue != null);
            statement = ReplaceDistinctOrderByWithRowNumber(statement, q => q.Select.SkipValue != null);
            statement = ReplaceTakeSkipWithRowNumber(statement, query => query.Select.SkipValue != null && SqlProviderFlags.GetIsSkipSupportedFlag(query.Select.TakeValue, query.Select.SkipValue), true);

            return(statement.QueryType switch {
                QueryType.Delete => GetAlternativeDelete((SqlDeleteStatement)statement),
                QueryType.Update => GetAlternativeUpdate((SqlUpdateStatement)statement),
                _ => statement,
            });
Example #4
0
        public override SqlStatement TransformStatement(SqlStatement statement)
        {
            // DB2 LUW 9/10 supports only FETCH, v11 adds OFFSET, but for that we need to introduce versions into DB2 provider first
            statement = SeparateDistinctFromPagination(statement, q => q.Select.SkipValue != null);
            statement = ReplaceDistinctOrderByWithRowNumber(statement, q => q.Select.SkipValue != null);
            statement = ReplaceTakeSkipWithRowNumber(statement, query => query.Select.SkipValue != null && SqlProviderFlags.GetIsSkipSupportedFlag(query), true);

            return(statement.QueryType switch
            {
                QueryType.Delete => GetAlternativeDelete((SqlDeleteStatement)statement),
                QueryType.Update => GetAlternativeUpdate((SqlUpdateStatement)statement),
                _ => statement,
            });