| | 42 | == More stricter OGR SQL syntax to distinguish literals from identifiers == |
| | 43 | |
| | 44 | Current OGR SQL syntax interprets as equivalent single-quoting and double-quoting. However there are situations where using carefully single-quoting or double-quoting is the only way to understand the intent of the user. The SQL standard (at least as implemented in sqlite and postgresql) being : 'a_literal' and "a_identifier" (identifier being column or table name). See http://www.sqlite.org/lang_keywords.html |
| | 45 | |
| | 46 | Example : SELECT CONCAT('x',PRFEDEA) FROM poly is OK. But now imagine that the PRFEDEA field is in fact called DESC, which is a reserved SQL keyword, thus needing quoting. And here we realize that we can't distinguish between a literal and a field name (should we concat 'x' with 'DESC'-the-string of 'x' with 'DESC'-the-field ?), if we consider single and double quoting as equivalent... |
| | 47 | |
| | 48 | Not strictly an API/ABI issue, but fixing this would break user scripts/code/practice if they don't follow the SQL standard and use indifferently single and double-quotes. |
| | 49 | |
