You need a UNIQUE index on the PARENT KEY because when you operate on a child,
you need to be able to look up the PARENT. If there is no index on the PARENT
KEY then you have to do a table scan. A table scan of a billion parent records
many take quite some time.
Similarly, you need an index
Hello Yuri,
Friday, August 03, 2018, 12:06:14 AM, Yuri wrote:
> On 8/2/18 3:46 PM, Keith Medcalf wrote:
>> You are required to have a UNIQUE index on the PARENT KEYS in a foreign key
>> relationship.
>>
>> Depending on whether the PARENT:CHILD is 1:1 or 1:N you need either
>> a UNIQUE (1:1) or
On 8/2/18 3:46 PM, Keith Medcalf wrote:
You are required to have a UNIQUE index on the PARENT KEYS in a foreign key
relationship.
Depending on whether the PARENT:CHILD is 1:1 or 1:N you need either a UNIQUE
(1:1) or regular index on the child key.
Why is index on PARENT KEY in a foreign
It is. If you create the missing index then your "testcase" does not
demonstrate any slowdown.
After this line:
doSql(db, "create table a (id int PRIMARY KEY, name text, aid int not null,
FOREIGN KEY(aid) REFERENCES a(id))");
insert this line:
doSql(db, "create index aid on a (aid)");
On 8/2/18 3:17 PM, Keith Medcalf wrote:
.lint fkey-indexes
and it will tell you what indexes you forgot to create that cause the issue you
are seeing.
But this problem isn't about a missing index.
Yuri
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Many versions ago a CLI command (that is, the sqlite3 Command Line Interface)
was created so that folks would stop complaining about referential integrity
enforcement being slow when they did not create the indexes that were necessary
to enforce referential integrity (because failing to have
Well, ok, but it is not really creating an index drawing data from multiple
tables. The table definition part "interleaves" data with the same value for
the same column into a "cluster" of pages, and the creation of the index on the
cluster is an index of the "common column data".
Creating
On 8/2/18 7:02 AM, David Raymond wrote:
So for your test script there, try inserting a record with the violation ID a
little bit later and see if it suddenly speeds up again. In my Python version
of your script it does indeed speed back up again once the outstanding
violation is fixed.
The
On 2018/08/02 10:29 PM, Csányi Pál wrote:
Hi,
I just want to know why the following SQLite query does not work as I expected?
WITH RECURSIVE dates(dateD) AS ( VALUES('2015-10-03') UNION ALL SELECT
date(dateD, '+1 year') FROM dates WHERE date(dateD) <=
date('2016-11-01') ) SELECT max(dateD),
On 02/08/2018 20:50, Keith Medcalf wrote:
In no DBMS known can you index data sourced from multiple tables in the same index --
this applies to "Relational" databases and all other database models (such as
pure hierarchical, network, network extended, etc.) In all DBMS systems the contents of
Hi,
I just want to know why the following SQLite query does not work as I expected?
WITH RECURSIVE dates(dateD) AS ( VALUES('2015-10-03') UNION ALL SELECT
date(dateD, '+1 year') FROM dates WHERE date(dateD) <=
date('2016-11-01') ) SELECT max(dateD), count(dateD) FROM dates;
2017-10-03|3
which is
On 2 Aug 2018, at 7:44pm, John R. Sowden wrote:
> another point that I did not make clear. The accounting programs are not
> associated with the technical programs, different people, different security
> access. The tech databases and programs are in portable computers that go
> out in the
>SQLite3 stores the table (.DBF) and all the indexes associated with
>that table in a single file called a database. You can also have
>multiple tables in one database (rather than one table per file) and
>all the indexes associates with all those tables are stored in the
>same database file.
You misunderstand how dBase databases work. An index is created on a table
(.DBF file) and stored in an index file (.NDX). You can have multiple indexes
associated with a single .DBF file (which means multiple .NDX files). FoxPro
has a non-standard index format that permits the multiple
Hi,
On Thu, Aug 2, 2018 at 1:44 PM, John R. Sowden
wrote:
> another point that I did not make clear. The accounting programs are not
> associated with the technical programs, different people, different security
> access. The tech databases and programs are in portable computers that go
> out
another point that I did not make clear. The accounting programs are
not associated with the technical programs, different people, different
security access. The tech databases and programs are in portable
computers that go out in the field, but not the accounting, etc. There
indexes would
The "index" is on what's actually in the "table". So the index on each
database's tables are always up to date.
What you're saying is that each satellite database should have a complete, up
to date copy of the customer ID "table". The only way to do that would be to
have a centrally accessible
Hi,
On Thu, Aug 2, 2018 at 1:27 PM, John R. Sowden
wrote:
> I made a mistake. I should have said table, not database. My concern is if
> I have 4 databases each with tables associated with a particular use, like
> accounting, technical, etc., which may reside on different computers, how do
> I
I made a mistake. I should have said table, not database. My concern
is if I have 4 databases each with tables associated with a particular
use, like accounting, technical, etc., which may reside on different
computers, how do I keep the index in each database file current. I
assume that I
On 2 Aug 2018, at 6:11pm, John R. Sowden wrote:
> I do not want these databases to all reside in one sqlite file. How do I
> index each database on this customer account number when each database and
> associated index are in separate files? Is this what seems to be referred to
> as an
Each SQLite file will be its own database with its own tables and indexes. So
for each database you just define an index on the appropriate tables.
I'm not sure why you want multiple files, but it's fine. You can always have
one master db from which you ATTACH the others as needed. You just
I have been reviewing sqlite for a couple of years, but still use
foxpro. I have a question regarding an index issue.
Currently I have several types of databases (in foxpro, one per file)
that all point to an index of a common field, a customer account
number. The databases are for
On 8/1/18, Charles Leifer wrote:
> You can simply use:
>
> PRAGMA table_info('my_table')
>
> To get a list of columns, which you can check against and then
> conditionally add your column.
From C-code, you can use the sqlite_table_column_metadata() interface
[1] to quickly check for the
The way I it happens with deferred foreign keys is this (Gut feeling
from observations. Experts please correct me if I'm way off):
Keep track with an integer, let's call it "netBroken"
While netBroken = 0 then when you insert a row you don't have to check if
anything references it, only if it
This is also a problem on FreeBSD, I just haven’t noticed it because the ports
guys are on top of keeping their sqlite3 build up to date, and they do the
smart thing and build --with-system-sqlite.
If you’re building sqlite-autoconf-3xx/tea, then why would the “system
sqlite” ever be
On Thu, Aug 2, 2018 at 10:34 AM Keith Medcalf wrote:
>
> Yes. Look at the CREATE TABLE for table A (completely ignore table B as
> it serves no purpose whatsoever)
>
Rah, silly me... I assumed A.aid referenced B.id. Why have a B table at all
then.
> Also, if you create an index on the
This is the line that create the violation:
sprintf(s, "insert into a values(%d, 'The name field for %d', %d)",
NROWS+i, i, NROWS+i+VIOLATION);
if VIOLATION is 0 then you are inserting a record with id = NROWS+i and aid =
NROWS+i. Since the referential constraint is that aid
Yes. Look at the CREATE TABLE for table A (completely ignore table B as it
serves no purpose whatsoever)
If you change the database to write to a database on disk so you can examine it
after (or modify doSql so that it outputs the SQL so that you can read it)
everything will become much
I didn't say I knew how you to do it in SQLitespeed, I said you your
use-case was very likely the same as mine.
I did notice the new keyword API and will move to 3.24 so I can use that.
Will look further into using explain to solve this problem, but guess the
output of explain may change in future
On Thu, Aug 2, 2018 at 9:35 AM Keith Medcalf wrote:
> You observe no violation when VIOLATION is 0 because there is no
> referential integrity violation to report ...
>
Really Keith? Parent IDs are in range [0, NROWS)
Child/FK IDs inserted are in range [NROWS, 2*NROWS)
How's that not an FK
Our application is an ASP.NET MVC application with an N-Tier architecture
running on Mono in Linux. Interaction with SQLite DB is done
through ADO.Net using System.Data.SQLite provider.
Can you suggest best approach for implementing and applying migrations to
the DB?
On Thu, Aug 2, 2018 at 12:57 AM Yuri wrote:
> The attached testcase injects the foreign key violation into a long
> transaction. This makes the remainder of the transaction much slower,
> even though the foreign key is deferred, and should only be checked in
> the end of the transaction.
>
You observe no violation when VIOLATION is 0 because there is no referential
integrity violation to report ...
However, you are correct that when inserting data the as shown in your code
(where there is a referential integrity violation) the insertion is much slower
after the violation
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