![]() ![]() I'm aware any solution you'll come up with will take time to implement, especially since we're hitting a limitation of SQLite (compared to other database backends). Having a single flag on an attribute is way more practical than adding the same code over and over again to every query using that attribute. I think the case_insensitive parameter would be more useful, especially for attributes we want to be "user-searchable". If I wanted to use an SQL-like syntax I'd use the raw_sql/ select_by_sql functions Pony is already providing us with. ![]() Plus it would defeat the purpose of providing a pythonic way to write queries. lower() to the operand one wants to use with in or startswith/ endswith. You need to look at using the COLLATE operator for case insensitive comparison. So the displayname values with an '' in them are at the top, and then ordered by the displayname value in that each grouping (based on the CASE statement). ![]() But I chose to design my database schemas to be case insensitive on some fields, knowing it wouldn't be consistent with the Python language, for the ease of use it brings.Īdding like and ilike functions would be the same as not adding or adding. The ORDER BY clause supports more than one column, but the priority is read left to right. I'm also well aware that string operations are case sensitive in Python. I totally understand and that's what I would expect when working with a backend-agnostic library. I think we can add direct support of like and ilike (case-insensitive like) functions to Pony, so instead of But in SQLite the function that implements LIKE operator does not receive information about collations of its arguments, so it is not possible for LIKE in SQLite to be case-insensitive only when it is necessary. Turns out this works, the column gets created as a COLLATE NOCASE column and all your searches / ordering against it are now case insensitive and your query. In other databases, when LIKE operates on columns with case-insensitive collation, it provides case-insensitive result. These operations in Python are case-sensitive so it makes sense to keep them case-sensitive in query, so the result is the same as in Python. It is used for translation of Python string operations, like, in or startswith/ enswith. 'i' is uppercased to '' (U+130 Latin Capital I with dot above) UTF-8 strings add extra complexity to the question. The simple counter-example is 'i' <> 'I' The naive answer is no, but in Turkish these strings are unequal.Because of this, in 0.7.5 we made LIKE case-sensitive for ASCII symbols in SQLite.Īlso, at this moment we don't provide LIKE operator directly in Pony. There is no locale-independent, case-insensitive way of sorting strings. In other databases LIKE is case-sensitive for all symbols, except when special case-insensitive collation is specified. By default in SQLite LIKE is case-insensitive for ASCII symbols, but is case-sensitive for Unicode symbols. The default LIKE implementation in SQLite differs from another databases. Normalize all strings to the same case, - does not matter lower or upper: SELECT FROM items WHERE LOWER(text) 'string in lower case' - 3. Or, developers can write their own overloads based on their own Unicode-aware comparison routines already contained within their project.Our goal is maximum possible compatibility between different databases, so the same Pony query returns the same result in all databases. Use a NOCASE collation - (we will look at other ways for applying collations later): SELECT FROM items WHERE text 'String in AnY case' COLLATE NOCASE - 2. The SQLite source code includes an "ICU" extension that does these overloads. The application can overload the built-in NOCASE collating sequence (using sqlite3_create_collation()) and the built-in like(), upper(), and lower() functions (using sqlite3_create_function()). Instead of providing full Unicode case support by default, SQLite provides the ability to link against external Unicode comparison and conversion routines. The SQLite developers reason that any application that needs full Unicode case support probably already has the necessary tables and functions and so SQLite should not take up space to duplicate this ability. The reason for this is that doing full Unicode case-insensitive comparisons and case conversions requires tables and logic that would nearly double the size of the SQLite library. You can just convert everything to lowercase for the purposes of sorting: SELECT FROM NOTES ORDER BY LOWER (title) If you want to make sure that the uppercase ones still end up ahead of the lowercase ones, just add that as a secondary sort: SELECT FROM NOTES ORDER BY LOWER (title), title Share. ![]() The default configuration of SQLite only supports case-insensitive comparisons of ASCII characters. Quote (18) Case-insensitive matching of Unicode characters does not work. ![]()
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