I have a column with a normal INDEX, and I would like to turn it into an
UNIQUE index, but I'm a bit worried about the performance implications for
inserts. Can someone give some insight into how UNIQUE is implemented in
SQLite, does it create extra tables compared to a normale index, are there
Fabian fabianpi...@gmail.com wrote:
I have a column with a normal INDEX, and I would like to turn it into an
UNIQUE index, but I'm a bit worried about the performance implications for
inserts. Can someone give some insight into how UNIQUE is implemented in
SQLite, does it create extra tables
No, a UNIQUE index and a regular index are implemented the exact same way.
It's just that, at INSERT and UPDATE time, after finding a proper place to
insert the new value, an additional check is made that the place isn't
already occupied.
So the only overhead for UNIQUE is that extra
On 23 Oct 2011, at 3:49pm, Fabian wrote:
So the only overhead for UNIQUE is that extra check? [snip]
Right. When doing an INSERT or UPDATE, it checks to see whether the value it's
trying to add to the index already exists in the index. If it does, the result
is an error. There is no
2011/10/23 Simon Slavin slav...@bigfraud.org
In this example, the indexed column is a text column. The text fields
could have been very long, and checking long text fields for uniqueness can
involve comparing every byte. Nevertheless, I do not understand the results
you quoted. I wonder
A. Pagaltzis [EMAIL PROTECTED] wrote:
It's a pity that INSERT OR IGNORE (apparently?) does not set
last_insert_id properly regardless of outcome,
Consider this case:
CREATE TABLE t1(x INTEGER PRIMARY KEY, y UNIQUE, z UNIQUE);
INSERT INTO t1 VALUES(1,'a','b');
INSERT INTO t1
Shane Harrelson [EMAIL PROTECTED] wrote:
I have two tables, an Objects table with a foreign key into a second
Strings table which is composed of unique values. It is a many to
one relationship, that is, several Objects may reference the same
String. When an Object is added, its associated
when i try to insert a row into a table that has a UNIQUE constraint
on a column, and I get the SQLITE_CONSTRAINT result code because i'm
inserting a duplicate value, is there anyway to determine the rowid of
the conflict?
looking at the internals of the VDBE, i found that the rowid of the
Shane Harrelson [EMAIL PROTECTED] wrote:
when i try to insert a row into a table that has a UNIQUE constraint
on a column, and I get the SQLITE_CONSTRAINT result code because i'm
inserting a duplicate value, is there anyway to determine the rowid of
the conflict?
looking at the internals of
On 1/31/07, [EMAIL PROTECTED] [EMAIL PROTECTED] wrote:
Shane Harrelson [EMAIL PROTECTED] wrote:
when i try to insert a row into a table that has a UNIQUE constraint
on a column, and I get the SQLITE_CONSTRAINT result code because i'm
inserting a duplicate value, is there anyway to determine
Shane Harrelson wrote:
On 1/31/07, [EMAIL PROTECTED] [EMAIL PROTECTED] wrote:
The official way to find the conflicting entry is to do a query.
SELECT rowid FROM table WHERE uniquecolumn=?;
Thank you for the reply. I assumed this was most likely the case, and
as I said in my original
Hi Shane,
On Wed, 31 Jan 2007 09:29:24 -0500, you wrote:
On 1/31/07, [EMAIL PROTECTED] [EMAIL PROTECTED] wrote:
Shane Harrelson [EMAIL PROTECTED] wrote:
when i try to insert a row into a table that has a UNIQUE constraint
on a column, and I get the SQLITE_CONSTRAINT result code because i'm
On 1/31/07, Dennis Cote [EMAIL PROTECTED] wrote:
Shane Harrelson wrote:
On 1/31/07, [EMAIL PROTECTED] [EMAIL PROTECTED] wrote:
The official way to find the conflicting entry is to do a query.
SELECT rowid FROM table WHERE uniquecolumn=?;
Thank you for the reply. I assumed this was
On Wed, Jan 31, 2007 at 05:23:29PM -0500, Shane Harrelson wrote:
I have two tables, an Objects table with a foreign key into a second
Strings table which is composed of unique values. It is a many to
one relationship, that is, several Objects may reference the same
String. When an Object
Shane Harrelson [EMAIL PROTECTED] wrote:
I have two tables, an Objects table with a foreign key into a second
Strings table which is composed of unique values. It is a many to
one relationship, that is, several Objects may reference the same
String. When an Object is added, its associated
when i try to insert a row into a table that has a UNIQUE constraint
on a column, and I get the SQLITE_CONSTRAINT result code because i'm
inserting a duplicate value, is there anyway to determine the rowid of
the conflict?
looking at the internals of the VDBE, i found that the rowid of the
Hi,
I need to create a unique constraint on a column of type varchar, but it is
not case sensitive by default.
Does any one know how to make a unique constraint case sensitive?
CREATE TABLE abc(a UNIQUE COLLATE NOCASE);
Bear in mind that the NOCASE collation sequence only knows about
Hi,
I need
to create a unique constraint on a column of type varchar, but it is not case
sensitive by default.
Does any one know how to make a unique constraint case sensitive?
Thanks
and best regards,
Ajay Sonawane
18 matches
Mail list logo
