>>>>> Glynn Clements <[EMAIL PROTECTED]> writes:
>>>>> SQLite doesn't have VARCHAR. If you create a VARCHAR column, the
>>>>> driver translates it to TEXT. The size you specify when the table
>>>>> is created isn't stored anywhere.
>> Not exactly. While I don't know of the GRASS SQLite driver
>> specifics, the CREATE TABLE commands are preserved by SQLite:
[...]
>> Of course, any width limit specified via VARCHAR () is ignored by
>> SQLite itself.
> Interesting. But not particularly useful unless we add our own SQL
> parser to the SQLite driver.
> Well, it should only need to handle
> CREATE TABLE statements, but it would still need to understand
> exactly the syntax which SQLite supports (and the table might have
> been created by a future version).
[...]
> IOW, change db/drivers/sqlite/describe.c to parse the sqlite_master
> table according to the syntax used by
> db/drivers/sqlite/create_table.c.
Hm. Now I see sqlite3_column_decltype () in the SQLite API
reference?
[...]
>> IIUC, the very reason to allow SQL type specifications to be used in
>> CREATE TABLE was the interoperability with other SQL
>> implementations.
> SQLite allows them, but essentially ignores them (other than the
> information it puts into sqlite_master).
That's the point -- while it behaves its own way, it allows
standards-compliant database schemata to be reused with little
or no modification. (Or, rather, it relies on de-facto
standards, for that matter.)
> If you create a VARCHAR(10) column, it will happily allow you to
> store a 1000-character string in that column, and to retrieve it
> without truncation.
Yes.
>> But then, don't the major SQL RDBMS support the TEXT type? It has
>> unlimited width and thus implies no incompatibility with SQLite.
> They support the TEXT type, but the DBMI seems to assume fixed sizes,
> e.g. the aforementioned problem with the PostgreSQL driver failing to
> report the size for TEXT fields.
> The MySQL driver simply reports the length reported by MySQL; I have
> no idea what that will be for TEXT columns.
Shouldn't there be a separate value for the ``no size limit''
case?
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