[SailfishDevel] SQLite: ON DELETE CASCADE with Foreign Keys not working

[TE]

Sorry for being ambiguous. It returns: {"foreign_keys":0}


On 24.08.2016 15:53, David Greaves wrote:
> What does
>
>  function queryForeignKeysEnabled()
>  {
>      instance().transaction(function(tx) {
>          var rs = tx.executeSql("PRAGMA foreign_keys = ON; PRAGMA
> foreign_keys;");
>          console.log(JSON.stringify(rs.rows.item(0)))
>      });
>  }
>
> return?
>
> David
>
> On 24/08/16 13:45, TE wrote:
>> Hello Matthias,
>>
>> thanks for the quick reply! I access the database from the QML/JS
>> domain. To open a connection I use the following function:
>>
>> function instance()
>> {
>>     var db = Storage.LocalStorage.openDatabaseSync("Db", "", "Nodes",
>> 5000000);  /* DB Size: 5MB */
>>     db.transaction(function(tx) {
>>         tx.executeSql("PRAGMA foreign_keys = ON;");
>>     });
>>     return db
>> }
>>
>> The following test function
>>
>> function queryForeignKeysEnabled()
>> {
>>     instance().transaction(function(tx) {
>>         var rs = tx.executeSql("PRAGMA foreign_keys;");
>>         console.log(JSON.stringify(rs.rows.item(0)))
>>     });
>> }
>>
>> returns
>>
>> {"foreign_keys":0}.
>>
>> Can you map this implementation to your C++ code and tell the
>> difference?
>>
>> Cheers,
>> Thomas
>>
>>
>>
>>
>> On 24.08.2016 13:54, Matthias Fehring wrote:
>>> Hello Thomas,
>>>
>>> for me foreign key support is working. Directly after establishing the
>>> connection to the SQLite database (QSqlDatabase::open()) I use
>>> QSqlQuery to
>>> execute "PRAGMA foreign_keys = ON".
>>>
>>> I think you have to do it every time you open a closed database, so I
>>> implemented it in my database connection methods that it is executed
>>> if the
>>> database connection was closed before.
>>>
>>> Best greetings
>>> Matthias
>>>
>>>
>>> Am Mittwoch, 24. August 2016, 12:39:04 CEST schrieb TE:
>>>> Hello fellow devs,
>>>>
>>>> I have two SQLite tables. The second table references a key from the
>>>> first table as foreign key. Now when I delete a row in the first
>>>> table I
>>>> want all rows from the second table referencing the deleted key to be
>>>> deleted as well. For this the action ON DELETE CASCADE seems to be
>>>> appropriate. Unfortunately this doesn't work and the corresponding
>>>> rows
>>>> in the second table are *not* deleted.
>>>>
>>>> Here are the table definitions:
>>>>
>>>> First table:
>>>> CREATE TABLE IF NOT EXISTS NodeMetaData (id INTEGER PRIMARY KEY,
>>>> parentId INTEGER);
>>>>
>>>> Second table:
>>>> CREATE TABLE IF NOT EXISTS NodeConcreteData (refId INTEGER NOT NULL,
>>>> FOREIGN KEY(refId) REFERENCES NodeMetaData(id) ON DELETE CASCADE);
>>>>
>>>> In the sqlite docs, it is mentioned that foreign key support has to be
>>>> acitvated. So I tried tx.executeSql("PRAGMA foreign_keys = ON;"). But
>>>> the query tx.executeSql("PRAGMA foreign_keys;") returns 0.
>>>>
>>>> When I recreate the scenario in an interactive SQLite session, the
>>>> above
>>>> works (PRAGMA foreign_keys = ON has to be executed).
>>>>
>>>> Any ideas?
>>>> Is the SFOS Qt lib compiled with foreign key support?
>>>> What am I missing?
>>>>
>>>> Many thanks in advance!
>>>> Thomas
>>>> _______________________________________________
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>>>
>>>
>>>
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>>
>>
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