I'm trying to export/import a BD from one system to another but the import fails with the following error:
ERROR 1062 (23000) at line 8232: Duplicate entry '0-3-30168717-com_liferay_product_navigation_product_menu_web_...' for key 'IX_C7057FF7'
That table is defined as such:
CREATE TABLE `PortletPreferences` (
`portletPreferencesId` bigint(20) NOT NULL,
`ownerId` bigint(20) DEFAULT NULL,
`ownerType` int(11) DEFAULT NULL,
`plid` bigint(20) DEFAULT NULL,
`portletId` varchar(200) DEFAULT NULL,
`preferences` longtext DEFAULT NULL,
`mvccVersion` bigint(20) NOT NULL DEFAULT 0,
`companyId` bigint(20) DEFAULT NULL,
PRIMARY KEY (`portletPreferencesId`),
UNIQUE KEY `IX_C7057FF7` (`ownerId`,`ownerType`,`plid`,`portletId`),
In the mysql dump file, I see these two entries:
(31453178,0,3,30168717,'com_liferay_product_navigation_product_menu_web_portlet_ProductMenuPortlet','<portlet-preferences />',0,10132)
(31524539,0,3,30168717,'com_liferay_product_navigation_product_menu_web_portlet_ProductMenuPortlet','<portlet-preferences />',0,10132)
So, yep, there are two entries with the same unique key. How is that possible?!?
Knowing this, I ran the following select statement against the source DB:
select portletPreferencesId, ownerId, ownerType, plid, portletId from PortletPreferences where ownerId = 0 AND ownerType = 3 AND plid = 30168717 AND portletId like 'com_liferay_product_navigation_product_menu_web%';
And it outputs just ONE LINE!
+----------------------+---------+-----------+----------+----------------------------------------------------------------------------+
| portletPreferencesId | ownerId | ownerType | plid | portletId |
+----------------------+---------+-----------+----------+----------------------------------------------------------------------------+
| 31524539 | 0 | 3 | 30168717 | com_liferay_product_navigation_product_menu_web_portlet_ProductMenuPortlet |
+----------------------+---------+-----------+----------+----------------------------------------------------------------------------+
By the portletPreferencesId field, it outputs the second entry in the dump file. So I did one more select for the other row as such:
select portletPreferencesId, ownerId, ownerType, plid, portletId from PortletPreferences where portletPreferencesId = 31453178;
And I get:
+----------------------+---------+-----------+----------+----------------------------------------------------------------------------+
| portletPreferencesId | ownerId | ownerType | plid | portletId |
+----------------------+---------+-----------+----------+----------------------------------------------------------------------------+
| 31453178 | 0 | 3 | 30168717 | com_liferay_product_navigation_product_menu_web_portlet_ProductMenuPortlet |
+----------------------+---------+-----------+----------+----------------------------------------------------------------------------+
My question is, what's going on?!? Why is that entry not output by the first select statement and why is it there in the first place if those fields were supposed to be unique???
I have a bad feeling about the state of the source database :-( Oh, and that's just one. I have multiple duplicate keys like that in that table :-(
Thanks
There are occasional bugs like MDEV-15250 that can cause duplicate entries to occur.
Sometimes you may not see these as parts of the optimizer expect only a single row because of the unique constraint so won't search beyond it. Maybe a query across a range including the entries would be more likely to show it (which is what mysqldump would have done).
If you don't think its related to ALTER TABLE occurring at the same time as insertions (like MDEV-15250), and have a good hunch as the set of operations on the table that may have escaped the unique key enforcement, can you please create a bug report.
Is there a way to get a list of tables that have one-on-one relationship to a given table in SQLite3?
For example, here table ab has a one-on-one relationship with both table abc and abd. Is there a query or queries to return abc and abd for the given table name ab?
-- By default foreign key is diabled in SQLite3
PRAGMA foreign_keys = ON;
CREATE TABLE a (
aid INTEGER PRIMARY KEY
);
CREATE TABLE b (
bid INTEGER PRIMARY KEY
);
CREATE TABLE ab (
aid INTEGER,
bid INTEGER,
PRIMARY KEY (aid, bid)
FOREIGN KEY (aid) REFERENCES a(aid)
FOREIGN KEY (bid) REFERENCES b(bid)
);
-- tables 'ab' and 'abc' have a one-on-one relationship
CREATE TABLE abc (
aid INTEGER,
bid INTEGER,
name TEXT NOT NULL,
PRIMARY KEY (aid, bid) FOREIGN KEY (aid, bid) REFERENCES ab(aid, bid)
);
-- tables 'ab' and 'abd' have a one-on-one relationship
CREATE TABLE abd (
aid INTEGER,
bid INTEGER,
value INTEGER CHECK( value > 0 ),
PRIMARY KEY (aid, bid) FOREIGN KEY (aid, bid) REFERENCES ab(aid, bid)
);
CREATE TABLE w (
id INTEGER PRIMARY KEY
);
The following tedious precedure may get me the list of tables I want:
Get primary keys for table ab:
SELECT l.name FROM pragma_table_info('ab') as l WHERE l.pk > 0;
get foreign keys for other tables (this case is for table abd):
SELECT * from pragma_foreign_key_list('abd');
Do parsing to get what the list of tables of one-on-one relationships.
However, there must exist a more elegant way, I hope.
For SQL Server, there are sys.foreign_keys and referenced_object_id avaible (see post). Maybe there is something similar to that in SQLite?
Edit: adding two more tables for test
-- tables 'ab' and 'abe' have a one-on-one relationship
CREATE TABLE abe (
aid INTEGER,
bid INTEGER,
value INTEGER CHECK( value < 0 ),
PRIMARY KEY (aid, bid) FOREIGN KEY (aid, bid) REFERENCES ab
);
-- tables 'ab' and 'abf' have a one-on-one relationship
CREATE TABLE abf (
aidQ INTEGER,
bidQ INTEGER,
value INTEGER,
PRIMARY KEY (aidQ, bidQ) FOREIGN KEY (aidQ, bidQ) REFERENCES ab(aid, bid)
);
Edit: verify FK for table abe
sqlite> PRAGMA foreign_keys;
1
sqlite> .schema abe
CREATE TABLE abe (
aid INTEGER,
bid INTEGER,
value INTEGER CHECK( value < 0 ),
PRIMARY KEY (aid, bid) FOREIGN KEY (aid, bid) REFERENCES ab
);
sqlite> DELETE FROM abe;
sqlite> INSERT INTO abe (aid, bid, value) VALUES (2, 1, -21);
sqlite> INSERT INTO abe (aid, bid, value) VALUES (-2, 1, -21);
Error: FOREIGN KEY constraint failed
sqlite> SELECT * FROM ab;
1|1
1|2
2|1
Alternative
Although not a single query solution the following only requires submission/execution of a series of queries and is therefore platform independent.
It revolves around using two tables:-
a working copy of sqlite_master
a working table to store the the output of SELECT pragma_foreign_key_list(?)
Both tables are created via a CREATE-SELECT, although neither has any rows copied, so the tables are empty.
A trigger is applied to the working copy of sqlite_master to insert into the table that stores the result of SELECT pragma_foreign_key_list(table_name_from_insert);
The relevant rows are copied from sqlite_master via a SELECT INSERT and thus the triggering populates the store table.
The following is the testing code :-
DROP TABLE IF EXISTS fklist;
DROP TABLE IF EXISTS master_copy;
DROP TRIGGER IF EXISTS load_fklist;
/* Working version of foreign_key_list to store ALL results of SELECT pragma_foreign_key_list invocation */
CREATE TABLE IF NOT EXISTS fklist AS SELECT '' AS child,*
FROM pragma_foreign_key_list((SELECT name FROM sqlite_master WHERE type = 'not a type' LIMIT 1));
/* Working version of sqlite master */
CREATE TABLE IF NOT EXISTS master_copy AS SELECT * FROM sqlite_master WHERE type = 'not a type';
/* Add an after insert trigger for master copy to add to fklist */
CREATE TRIGGER IF NOT EXISTS load_fklist
AFTER INSERT ON master_copy
BEGIN
INSERT INTO fklist SELECT new.name,* FROM pragma_foreign_key_list(new.name);
END
;
/* Populate master_copy from sqlite_master (relevant rows)
and thus build the fklist
*/
INSERT INTO master_copy SELECT *
FROM sqlite_master
WHERE type = 'table'
AND instr(sql,' REFERENCES ') > 0
;
SELECT * FROM fklist;
DROP TABLE IF EXISTS fklist;
DROP TABLE IF EXISTS master_copy;
DROP TRIGGER IF EXISTS load_fklist;
Using a similar test base as per the previous answer the above results in :-
Is there a way to get a list of tables that have one-on-one relationship to a given table in SQLite3?
Not with certainty as coding a Foreign Key constraint does not define a relationship (rather it supports a relationship), that is relationships can exists without a FK constraint.
A Foreign Key constraint defines:-
a) a rule that enforces referential integrity
b) optionally maintains/alters referential integrity when the referred to column is changed (ON DELETE and ON UPDATE )
As such looking at the Foreign Key List only tells you where/if a FK constraint has been coded.
Saying that the following will get the tables with the constraint and the referenced tables.
More elegant is a matter of opinion, so it's up to you :-
WITH cte_part(name,reqd,rest) AS (
SELECT name,'',substr(sql,instr(sql,' REFERENCES ') + 12)||' REFERENCES '
FROM sqlite_master
WHERE sql LIKE '% REFERENCES %(%'
UNION ALL
SELECT
name,
substr(rest,0,instr(rest,' REFERENCES ')),
substr(rest,instr(rest,' REFERENCES ') + 12)
FROM cte_part
WHERE length(rest) > 12
)
SELECT DISTINCT
CASE
WHEN length(reqd) < 1 THEN name
ELSE
CASE substr(reqd,1,1)
WHEN '''' THEN substr(replace(reqd,substr(reqd,1,1),''),1,instr(reqd,'(')-3)
WHEN '[' THEN substr(replace(replace(reqd,'[',''),']',''),1,instr(reqd,'(')-3)
WHEN '`' THEN substr(replace(reqd,substr(reqd,1,1),''),1,instr(reqd,'(')-3)
ELSE substr(reqd,1,instr(reqd,'(')-1)
END
END AS tablename
FROM cte_part
;
As an example of it's use/results :-
screenshot from Navicat
Here's an adaptation of the above that includes, where appropriate, the child table that references the parent :-
WITH cte_part(name,reqd,rest) AS (
SELECT name,'',substr(sql,instr(sql,' REFERENCES ') + 12)||' REFERENCES '
FROM sqlite_master
WHERE sql LIKE '% REFERENCES %(%'
UNION ALL
SELECT
name,
substr(rest,0,instr(rest,' REFERENCES ')),
substr(rest,instr(rest,' REFERENCES ') + 12)
FROM cte_part
WHERE length(rest) > 12
)
SELECT DISTINCT
CASE
WHEN length(reqd) < 1 THEN name
ELSE
CASE substr(reqd,1,1)
WHEN '''' THEN substr(replace(reqd,substr(reqd,1,1),''),1,instr(reqd,'(')-3)
WHEN '[' THEN substr(replace(replace(reqd,'[',''),']',''),1,instr(reqd,'(')-3)
WHEN '`' THEN substr(replace(reqd,substr(reqd,1,1),''),1,instr(reqd,'(')-3)
ELSE substr(reqd,1,instr(reqd,'(')-1)
END
END AS tablename,
CASE WHEN length(reqd) < 1 THEN '' ELSE name END AS referrer
FROM cte_part
;
Example of the Result :-
the artists table is referenced by albums as the SQL used to create the albums table is CREATE TABLE 'albums'([AlbumId] INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL ,[Title] TEXT NOT NULL ,[ArtistId] INTEGER NOT NULL , FOREIGN KEY ([ArtistId]) REFERENCES 'artists'([ArtistId]))
i.e. FOREIGN KEY ([ArtistId]) REFERENCES 'artists'([ArtistId]))
the employees table is self-referencing as per CREATE TABLE 'employees'(.... REFERENCES 'employees'([EmployeeId]))
Additional re comment:-
(I am still trying to understand your code...)
The code is based upon selecting rows from sqlite_master where the row is for a table (type = 'table'), as opposed to an index, trigger or view and where the sql column contains the word REFERENCES with a space before and after and there is a following left parenthesis.
The last condition used to weed out the likes of CREATE TABLE oops (`REFERENCES` TEXT, `x REFERENCES Y`);
For each selected row 3 columns are output:-
name which is the name of the table as extracted from the name column of sqlite_master,
reqd is initially an empty string (i.e. initial)
rest the rest of sql that follows the referred to table name with suffixed with REFERENCES.
The UNION ALL adds rows that are built upon what is newly added to the CTE, i.e. the three columns are extracted as per :-
name is the name
reqd is the sql from the rest column up until the first REFERENCES term (i.e. the table and referenced column(s))
rest is the sql from after the REFERENCES term
As with any recursion the end needs to be detected, this is when the entire sql statement has been reduced to being less than 12 (i.e the length of " REFERENCES ", the term used for splitting the sql statement).
This is what is termed as a RECURSIVE CTE
Finally the resultant CTE is then queried. If the reqd field is empty then the tablename column is the name column otherwise (i.e. the reqd column contains data(part of the sql)) the table name is extracted (part up to left parenthesis if not enclosed (`,' or [ with ])) or extracted from between the enclosure.
The following is what the final query results in if all the CTE columns are included (some data has been truncated):-
As can clearly be seen the extracted sql progressively reduces
The answer is intended as in-principle and has not been extensively tested to consider all scenarios, it may well need tailoring.
SqlServer
Suppose I have 2 tables:
Table 1 - having column A
Table 2 - having column B [Bit] Not Null
Is it possible to have a Check Constraint, such that value of Column B can be "0", only when Column A is NOT NULL.
OR put it other way, value of Column B can be "1", only when Column A is NULL.
Thanks in advance.
Assuming that these tables are already related by a suitable foreign key, we can implement this check using a computed column and a new foreign key.
Make sure you read to the end
So if we have:
CREATE TABLE Table1 (
Table1ID char(5) not null,
ColumnA int null,
constraint PK_Table1 PRIMARY KEY (Table1ID)
)
CREATE TABLE Table2 (
Table2ID char(7) not null,
Table1ID char(5) not null,
ColumnB bit not null,
constraint PK_Table2 PRIMARY KEY (Table2ID),
constraint FK_Table2_Table1 FOREIGN KEY (Table1ID) references Table1 (Table1ID)
)
We can run this script:
alter table Table1 add
ColumnBPrime as CAST(CASE WHEN ColumnA is NULL THEN 1 ELSE 0 END as bit) PERSISTED
go
alter table Table1 add constraint UQ_Table1_WithColumnBPrime UNIQUE (Table1ID, ColumnBPrime)
go
alter table Table2 add constraint FK_Table2_Table1_CheckColumnB FOREIGN KEY (Table1ID, ColumnB) references Table1 (Table1ID,ColumnBPrime)
Hopefully you can see how this enforces the relationship between the two tables1.
However, there's an issue. In T-SQL, any DML statement may only make changes to one table. So there's no way to issue an update that both changes whether ColumnA is null or not and changes Column B to suit it.
This is another good reason not to have Column B in the database at all - it's derived information, and in our quest to ensure it always matches its definition, we'd have to always delete from Table 2, update Table 1 and re-insert in Table 2.
1It's now a matter of personal taste whether you remove the previous foreign key or leave it in place as the "real" one.
I have the following SQLite table:
CREATE TABLE podcast_search (
_id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
search TEXT NOT NULL UNIQUE
)
Whenever a user inserts/updates a row in the table, I want to sort that row at the end of the table. Thus, if I insert the following values:
_id | search | sort
===================
1 | foo | 1
2 | bar | 2
3 | quiz | 3
And then later update the 1 row from foo to foo2, the values should look like:
_id | search | sort
===================
2 | bar | 2
3 | quiz | 3
1 | foo2 | 4
I've implemented this thusly:
CREATE TABLE podcast_search (
_id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
search TEXT NOT NULL UNIQUE,
update_date TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP
)
CREATE TRIGGER update_date_update_trigger
AFTER UPDATE ON podcast_search FOR EACH ROW
BEGIN
UPDATE podcast_search
SET update_date = CURRENT_TIMESTAMP
WHERE _id = OLD._id;
END
However, my unit tests require a 1000ms sleep between insert/update operations in order to reliably sort, and this amount of delay is very annoying for unit testing.
I thought I could implement a vector clock instead, but it seems that AUTOINCREMENT values only exist for primary key columns. Does SQLite offer any other AUTOINCREMENT or AUTOINCREMENT-like option?
I'm running this on Android P, but this should be a generic SQLite problem.
UPDATE
I'm now using an sort INTEGER NOT NULL UNIQUE column, and SELECT-ing the largest row in that column and manually incrementing it before an INSERT/UPDATE:
CREATE TABLE podcast_search (
_id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
search TEXT NOT NULL UNIQUE,
sort INTEGER NOT NULL UNIQUE
)
SELECT sort from podcast_search ORDER BY sort DESC
either increment sort in application code, or set it to 0
Could I do this in a TRIGGER instead?
I thought I could implement a vector clock instead, but it seems that
AUTOINCREMENT values only exist for primary key columns. Does SQLite
offer any other AUTOINCREMENT or AUTOINCREMENT-like option?
They are not in fact AUTOINCREMENT values rather a column with AUTOINCREMENT will be an alias of the rowid column; not because AUTOINCREMENT has been coded but because INTEGER PRIMARY KEY has been coded.
All coding AUTOINCREMENT does is add a constraint that an auto-generated value MUST be greater than any other existing or used value. This only in fact becomes apparent if when a rowid with the value of 9223372036854775807 exists. In which case an attempt to insert a new row with an auto-generated rowid (i.e. no value is specified for the rowid column or an alias thereof) will result in an SQLITE_FULL error.
Without AUTOINCREMENT and when the highest rowid is 9223372036854775807 (the highest possible value for a rowid) an attempt is made to use a free value, which would obviously be lower than 9223372036854775807.
SQLite Autoincrement
You may wish to note the very first line of the linked page which says :-
The AUTOINCREMENT keyword imposes extra CPU, memory, disk space, and
disk I/O overhead and should be avoided if not strictly needed. It is
usually not needed.
I can't see any need from your description.
So what you want is a means of assigning a value for the column that is to be sorted that is 1 greater than the highest current value for that column, so it becomes the latest for sorting purposes, a subquery that retrieves max(the_column) + 1 would do what you wish. This could be in an UPDATE, TRIGGER or in an INSERT.
rowid = max(rowid) + 1 is basically how SQLite assigns a value to rowid unless AUTOINCREMENT is used when 1 is added to the greater of max(rowid) and the value, for the respective table, obtained from the table sqlite_sequence (will only exist if AUTOINCREMENT is used). It is referencing and maintaining sqlite_sequence that incurs the penalties.
For example you could use the following (which eliminates the need for an additional column and the additional index) :-
-- SETUP THE DATA FOR TESTING
DROP TABLE IF EXISTS podcast_searchv1;
CREATE TABLE IF NOT EXISTS podcast_searchv1 (
_id INTEGER NOT NULL PRIMARY KEY,
search TEXT NOT NULL UNIQUE
);
INSERT INTO podcast_searchv1 (search)
VALUES('foo'),('bar'),('guide')
;
-- Show original data
SELECT * FROM podcast_searchv1;
-- DO THE UPDATE
UPDATE podcast_searchv1 SET search = 'new value', _id = (SELECT max(_id) + 1 FROM podcast_searchv1) WHERE search = 'foo';
-- Show the changed data
SELECT * FROM podcast_searchv1;
The results being :-
and then :-
I am trying to use this code to extract data from a big csv file and insert into a database. The schema of the
database is provided in the code. However, I am doing something wrong in the last line. The
code is giving me value error. I am using pandas to read the csv file. Could someone help me point out where am I going wrong ?
import pandas as pd
import sqlite3
conn = sqlite3.connect('newdb.sqlite')
cur = conn.cursor()
cur.executescript('''
DROP TABLE IF EXISTS Policy;
DROP TABLE IF EXISTS Statecode;
DROP TABLE IF EXISTS County;
DROP TABLE IF EXISTS Line;
DROP TABLE IF EXISTS Construction;
DROP TABLE IF EXISTS Point_Granularity;
CREATE TABLE Statecode (
id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT UNIQUE,
name TEXT UNIQUE
);
CREATE TABLE County (
id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT UNIQUE,
name TEXT UNIQUE
);
CREATE TABLE Line(
id INTEGER NOT NULL PRIMARY KEY
AUTOINCREMENT UNIQUE,
name TEXT UNIQUE);
CREATE TABLE Construction(
id INTEGER NOT NULL PRIMARY KEY
AUTOINCREMENT UNIQUE,
name TEXT UNIQUE);
CREATE TABLE Point_Granularity(
id INTEGER NOT NULL PRIMARY KEY
AUTOINCREMENT UNIQUE,
number INTEGER UNIQUE);
CREATE TABLE Policy (
id INTEGER NOT NULL PRIMARY KEY
AUTOINCREMENT UNIQUE,
policyID INTEGER ,
eq_site_line FLOAT,
hu_site_line INTEGER,
statecode_id INTEGER,
county_id INTEGER,
line_id INTEGER,
construction_id INTEGER,
point_granularity_id INTEGER
);
''')
df = pd.read_csv('FL_insurance_sample.csv')
for policy in df.policyID:
cur.execute('INSERT INTO Policy (policyID) VALUES (?)',policy)
conn.commit()
I believe, using policy.astype(int) should work for this case ? Could anyone confirm ?
Basically you don't want to loop through your data frames - you would loose all pandas benefits then and it'll be too slow as well. You want to work with data frames:
df = pd.read_csv('FL_insurance_sample.csv')
df.to_sql('Policy', conn)
PS you might want to "massage" your data before so it will fit into your table structure
PPS if you want a working example you should provide a sample of your input data - 5-10 rows would be enough