Sorry misread that you are attempting to write a custom collation. -----Ursprüngliche Nachricht----- Von: sqlite-users [mailto:sqlite-users-boun...@mailinglists.sqlite.org] Im Auftrag von Hick Gunter Gesendet: Donnerstag, 02. Februar 2017 09:06 An: 'SQLite mailing list' <sqlite-users@mailinglists.sqlite.org> Betreff: Re: [sqlite] Help with custom collation
The interface your (simple) function must support is: void xFunc(sqlite3_context*,int,sqlite3_value**) with the first parameter being the sqlite3_context, the second parameter being the number of arguments passed in, and the third parameter being an array of pointers to unprotected sqlite3_value objects To access the arguments, you must call one of the sqlite3_value() functions. When implementign an aggregate function, you must provide callbacks for aggregation (xStep) and returning the value (xFinal) See http://sqlite.org/c3ref/create_function.html Gunter -----Ursprüngliche Nachricht----- Von: sqlite-users [mailto:sqlite-users-boun...@mailinglists.sqlite.org] Im Auftrag von x Gesendet: Mittwoch, 01. Februar 2017 17:45 An: sqlite-users@mailinglists.sqlite.org Betreff: [sqlite] Help with custom collation The collation function used was as follows int Compare(void* Data, int Len1, const void *s1, int Len2, const void *s2) { const UTF8String *S1 = static_cast<const UTF8String*>(s1), *S2 = static_cast<const UTF8String*>(s2); return 0; } Which was registered with the following code if (sqlite3_create_collation(SQLiteDB, "Compare", SQLITE_UTF8, NULL, &Compare) != SQLITE_OK) throw Exception("Collation creation error"); The above is merely a tester where I’ve set a breakpoint at the ‘return 0’ line. I tried it with the following stmt ‘select ID from IDTbl order by Name collate Compare’. I’m having the following problems 1. When it stops at the breakpoint the debugger shows the Len1 and Len2 params with correct looking values but the S1 and S2 appear to point to NULL values. I just keep getting ‘???’ values. Am I casting wrongly or something. 1. If I change the select to ‘select ID from IDTbl order by ID collate Compare’ the Compare function is never entered. Is this because ID is an integer column? Is there no way to implement a custom collation on an integer column? 1. If I change the registration to if (sqlite3_create_collation16(SQLiteDB, "Compare", SQLITE_UTF16, NULL, &Compare) != SQLITE_OK) throw Exception("Collation creation error"); it seems to register OK but running the select yields a “no such collation sequence: Compare” error. Can any kind soul cast any light on this for me. PS I’m using Embarcadero C++ builder 10.1 Berlin on windows 10 with the sqlite3.c amalgamation included in my project. _______________________________________________ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users ___________________________________________ Gunter Hick Software Engineer Scientific Games International GmbH FN 157284 a, HG Wien Klitschgasse 2-4, A-1130 Vienna, Austria Tel: +43 1 80100 0 E-Mail: h...@scigames.at This communication (including any attachments) is intended for the use of the intended recipient(s) only and may contain information that is confidential, privileged or legally protected. Any unauthorized use or dissemination of this communication is strictly prohibited. If you have received this communication in error, please immediately notify the sender by return e-mail message and delete all copies of the original communication. Thank you for your cooperation. _______________________________________________ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users ___________________________________________ Gunter Hick Software Engineer Scientific Games International GmbH FN 157284 a, HG Wien Klitschgasse 2-4, A-1130 Vienna, Austria Tel: +43 1 80100 0 E-Mail: h...@scigames.at This communication (including any attachments) is intended for the use of the intended recipient(s) only and may contain information that is confidential, privileged or legally protected. Any unauthorized use or dissemination of this communication is strictly prohibited. If you have received this communication in error, please immediately notify the sender by return e-mail message and delete all copies of the original communication. Thank you for your cooperation. _______________________________________________ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
