I've the dump of a table of a database and I have to transfer the rows on a table with the same structure on a new database.
On the new table there are already some rows so I've to insert the new values only if the primary key is not already present.
As database I'm using Oracle 11.6.
...
INSERT INTO TABLE1 (KEY, FIELD1, FIELD2) VALUES ('1111111','aaa','xxx');
INSERT INTO TABLE1 (KEY, FIELD1, FIELD2) VALUES ('2222222','bbb','yyy');
INSERT INTO TABLE1 (KEY, FIELD1, FIELD2) VALUES ('3333333','ccc','zzz');
...
If the key '2222222' is already in the database how can I avoid to have an error from the execution of the query?
Thank you
You can do this for each record:
MERGE INTO TABLE1 mt
USING (
SELECT '2222222' as KEY,
'bbb' as FIELD1,
'yyy' as FIELD2
FROM dual
) t on (mt.key = t.key)
WHEN NOT MATCHED THEN
INSERT (KEY, FIELD1, FIELD2)
VALUES (t.KEY, t.FIELD1, t.FIELD2);
However, it might help to first insert everything in a temporary table TABLE1_TEMP.
then run only one merge statement:
MERGE INTO TABLE1 mt
USING (
SELECT KEY, -- more interesting
FIELD1, -- to merge all this
FIELD2 -- at once instead of
FROM TABLE1_TEMP -- just one record
) t on (mt.key = t.key)
WHEN NOT MATCHED THEN
INSERT (KEY, FIELD1, FIELD2)
VALUES (t.KEY, t.FIELD1, t.FIELD2);
Then drop TABLE1_TEMP
Related
In a sqlite3 database I would like to create a trigger on a view so that I can insert data over the view. Inside the trigger I would like to insert something in the tblmedia table. The id of the inserted row should be now also inserted into the tblbook as id.
In sqlite there are no variables. Otherwise I would store the returning value in the variable and would use it in the second query.
Can this even be achieved in sqlite?
Following my sql schema:
CREATE TABLE tblmedia(
id INTEGER PRIMARY KEY NOT NULL,
title VARCHAR NOT NULL,
raiting INTEGER,
file_name VARCHAR NOT NULL,
media_type TEXT NOT NULL
);
CREATE TABLE tblbook(
id INTEGER PRIMARY KEY NOT NULL,
author VARCHAR,
FOREIGN KEY (id) REFERENCES tblmedia(id) ON DELETE CASCADE
);
CREATE VIEW book AS
SELECT
m.id as id,
m.title as title,
b.author as author,
m.raiting as raiting,
m.file_name as file_name
FROM tblbook b
LEFT JOIN tblmedia m ON m.id = b.id;
CREATE TRIGGER insert_book
INSTEAD OF INSERT ON book
BEGIN
INSERT INTO tblmedia(title, raiting, file_name)
VALUES(new.title, new.raiting, new.file_name);
INSERT INTO tblbook(id, author)
VALUES (xx, new.author); -- xx should be the id from the previous insert
END
I need to understand how to add a statement that will delete the results of the following query:
I understand that a DELETE statement with a WHERE clause would normally be used, but because I'm SELECTING two different columns, the where clause doesn't accept the comma. I've not yet been able to figure out how to turn this into a CTE (but maybe that's overkill?) and then call it in a DELETE statement later (assuming that's even an option). Examples always have the DELETE FROM..., or WHICH statements, neither of which seem implementable under this code. Do I have to rewrite my code so it includes a WHICH statement?
SELECT field1, field2
FROM table
GROUP BY field1, field2
HAVING SUM(field3) IS NULL
Expecting to be able to institute a DELETE statement to delete the results of the query.
I believe that you could use (assuming that the table is not a WITHOUT ROWID table) :-
DELETE FROM mytable WHERE rowid IN (SELECT rowid FROM mytable GROUP BY field1, field2 HAVING SUM(field3) IS NULL);
An alternative using a CTE (where the CTE has been given the name deletions) would be :-
WITH deletions(rowid) AS (SELECT rowid
FROM mytable
GROUP BY field1, field2
HAVING SUM(field3) IS NULL
)
DELETE FROM mytable WHERE rowid IN (SELECT rowid FROM deletions);
note that mytable has been used as the table name instead of table.
Considering the comment
Primary key is field1
then :-
DELETE FROM mytable WHERE field1 IN (SELECT field1 FROM mytable GROUP BY field1, field2 HAVING SUM(field3) IS NULL);
could be used, this would then work whether or not the table is defined as a WITHOUT ROWID table, a similar change could be applied to the CTE version.
Notes
Using GROUP BY on a PRIMARY KEY, as it is UNIQUE, will result in as many groups and therefore rows, as there are rows. Effectively the query could be SELECT field1 FROM mytable WHERE field3 IS NULL and therefore the deletion could simply be DELETE FROM mytable WHERE field3 IS NULL.
If this were not the case and field1 was not the PRIMARY KEY, then the complication is that values per group that are not aggregated values are values from an arbitrarily selected row. In short you would delete 1 from a number of the rows that where grouped.
Good day SO,
I'm working on a program in PowerShell to manipulate an SQLite DB I created. I've never written a serious applications to utilize a DB so right now I'm super interested in optimizing my querys, so I'm really interested in feed back. My primary issue is I have a lot of data that I want to include in a separate table that may or not exist already. All my research really seemed to lead to perform an INSERT and let the UNIQUE constraints sort it out, than do a select on the new record which seemed like two table scans and inefficient. So my solution was Create a temp table, insert into the temp table FROM the table with data I want and perform an INSERT if the data was not in the temporary table. I'm a few drinks in tonight and haven't tested the code so please don't critique small typos, I just want to know if my methodology is out to lunch, and if so please provide better direction.
My table is as shown:
CREATE TABLE Processes (
pk INTEGER PRIMARY KEY AUTOINCREMENT
UNIQUE,
hostname INTEGER NOT NULL,
artifacttype INTEGER REFERENCES ArtifactType (pk),
processname INTEGER REFERENCES ProcessesName (pk),
filelocation INTEGER NOT NULL
REFERENCES files (pk),
pid INTEGER,
ppid INTEGER,
starttime INTEGER,
stoptime INTEGER,
token STRING,
logonid INTEGER,
exitstatus INTEGER,
threadcount INTEGER,
commandline INTEGER REFERENCES ProcessesCommandline (pk),
user INTEGER REFERENCES users (pk),
PeakVirtualSize INTEGER,
VirtualSize INTEGER,
PeakWorkingSetSize INTEGER,
suspicious BOOLEAN,
malicious BOOLEAN
);
Transaction:
#"
CREATE TEMPORARY TABLE IF NOT EXISTS Results(pk INTEGER, data TEXT);
INSERT INTO Results(pk, data) VALUES ((SELECT pk, name FROM ProcessesName WHERE name = #processname));
INSERT INTO ProcessesName(name) VALUES (SELECT #processname WHERE NOT EXISTS (SELECT pk FROM Results WHERE data = #processname));
INSERT INTO Results (pk, data) VALUES ((SELECT last_insert_row_id, #processname WHERE NOT EXISTS (SELECT pk FROM Results WHERE data =#processname)));
INSERT INTO Results(pk, data) VALUES ((SELECT pk, file FROM Files WHERE file = #filelocation));
INSERT INTO Files(file) VALUES (SELECT #filelocation WHERE NOT EXISTS (SELECT pk FROM Results WHERE data = #filelocation));
INSERT INTO Results (pk, data) VALUES ((SELECT last_insert_row_id, #filelocation WHERE NOT EXISTS (SELECT pk FROM Results WHERE data =#filelocation)));
INSERT INTO Results(pk, data) VALUES ((SELECT pk, commandline FROM ProcessesCommandline WHERE commandline = #commandline));
INSERT INTO ProcesseCommandline(commandline) VALUES (SELECT #commandline WHERE NOT EXISTS (SELECT pk FROM Results WHERE data = #commandline));
INSERT INTO Results (pk, data) VALUES ((SELECT last_insert_row_id, #filelocation WHERE NOT EXISTS (SELECT pk FROM Results WHERE data =#commandline)));
INSERT INTO Results(pk, data) VALUES ((SELECT pk, SID FROM Users WHERE SID = #SID));
INSERT INTO Users(SID) VALUES (SELECT #SID WHERE NOT EXISTS (SELECT pk FROM Results WHERE data = #filelocation));
INSERT INTO Results (pk, data) VALUES ((SELECT last_insert_row_id, #SID WHERE NOT EXISTS (SELECT pk FROM Results WHERE data =#SID)));
INSERT INTO processes(hostname, artifacttype, processname, filelocation, pid, ppid, starttime, threadcount, commandline, user, PeakVirtualSize, VirtualSize, PeakWorkingSetSize)
VALUES (#hostname, #artifacttype, (SELECT pk FROM Results WHERE data = #processname), (SELECT pk FROM Results WHERE data #filelocation), #pid, #ppid, #starttime, #threadcount, (SELECT pk FROM Results where data = #commandline), SELECT pk FROM Results WHERE data = #SID, #PeakVirtualSize, #VirtualSize, #PeakWorkingSetSize);
DROP TABLE Results;
"#
*there are a few foreign keys where the data is being tracked application side so no complex queries are required.
So my core question is, is there a more efficient way to do this?
Thanks guys!
I'm trying to insert a parent and child at the same time.
My idea is to insert the parent, get the id using SELECT last_insert_rowid() AS [Id] and use this id to insert the child
I can get each part of this working independently but not as a whole. This is what I currently have:
INSERT INTO ParentTable (Col1)
VALUES( 'test')
SELECT last_insert_rowid() AS [Id]
The above works - so far so good. Now I want to use the result of this in the child insert. This is what I have:
INSERT INTO ChildTable (col1, col2, ParentId)
VALUES( 1, 2, SELECT Id FROM (
INSERT INTO ParentTable (Col1)
VALUES( 'test')
SELECT last_insert_rowid() AS [Id]
);
I get this error:
near "SELECT": syntax error:
Can anyone point me in the right direction?
You can't use INSERT in SELECT statement. You should first insert and then use last inserted id:
INSERT INTO ParentTable (Col1) VALUES( 'test');
INSERT INTO ChildTable (col1, col2, ParentId)
VALUES(1,2, (SELECT last_insert_rowid()));
Since you want to insert many records with parent ID, here is a workaround:
BEGIN TRANSACTION;
CREATE TEMPORARY TABLE IF NOT EXISTS temp(id integer);
DELETE FROM temp;
INSERT INTO ParentTable (Col1) VALUES( 'test');
INSERT INTO temp SELECT last_insert_rowid();
INSERT INTO ChildTable (col1, col2, ParentId)
VALUES(1,2, (SELECT id FROM temp LIMIT 1));
.............
COMMIT;
DROP TABLE temp;
Or you can create a permanent table to this effect.
That SQLite.Net PCL driver assumes that you use the ORM: inserting an object will automatically read back and assign the autoincremented ID value.
If you're using raw SQL, you have to manage the last_insert_rowid() calls yourself.
Your idea is correct, but you have to do everything in separate SQL statements:
BEGIN; -- better use RunInTransaction()
INSERT INTO Parent ...;
SELECT last_insert_rowid(); --> store in a variable in your program
INSERT INTO Child ...;
...
END;
(SQLite is an embedded database and has no client/server communication overhead; there is no reason to try to squeeze everything into a single statement.)
I'm working on a SQLite Database. The database is already filled, but I want to refactor it. Here is a sample of what I need to do:
I currently have one table:
CREATE TABLE Cars (ID INTEGER PRIMARY KEY,
Name VARCHAR(32),
TopSpeed FLOAT,
EngineCap FLOAT);
I want to split this into two tables:
CREATE TABLE Vehicles (ID INTEGER PRIMARY KEY,
Name VARCHAR(32),
TopSpeed FLOAT);
CREATE TABLE Cars (ID INTEGER PRIMARY KEY,
VehicleID INTEGER CONSTRAINT FK_Cars REFERENCES [Vehicles](ID),
EngineCap FLOAT);
I have figured out to create a temporary table with the Cars table contents, and I can fill up the Vehicles table with the contents of the Cars table:
CREATE TEMPORARY TABLE Cars_temp AS SELECT * FROM Cars;
INSERT INTO Vehicles (Name, TopSpeed)
SELECT Name, TopSpeed FROM Cars_temp;
But I am still looking for a way to go over that same selection, while putting the EngineCap field into the new Cars table and somehow extracting the corresponding ID value from the Vehicles table to put into the VehicleID foreign key field on the Cars table.
I'm open for workaround or alternative approaches.
Thanks.
Since #mateusza did not provide an example, I've made one:
Suppose you have this table:
CREATE TABLE [Customer] (
[name] TEXT,
[street] TEXT,
[city] TEXT);
Now you want to move street and city into a separate table Address, so you'll end up with two tables:
CREATE TABLE [Customer2] (
[name] TEXT,
[addr] INTEGER);
CREATE TABLE [Address] (
[rowid] INTEGER NOT NULL,
[street] TEXT,
[city] TEXT,
PRIMARY KEY ([rowid])
);
(For this example, I'm doing the conversion in the same database. You'd probably use two DBs, converting one into the other, with an SQL ATTACH command.)
Now we create a view (which imitates our original table using the new tables) and the trigger:
CREATE VIEW Customer1 (name, street, city) AS
SELECT C.name, A.street, A.city FROM Customer2 AS C
JOIN Address as A ON (C.addr == A.rowid);
CREATE TEMP TRIGGER TempTrig INSTEAD OF INSERT ON Customer1 FOR EACH ROW BEGIN
INSERT INTO Address (street, city) SELECT NEW.street, NEW.city;
INSERT INTO Customer2 (addr, name) SELECT last_insert_rowid(), NEW.name;
END;
Now you can copy the table rows:
INSERT INTO Customer1 (name, street, city) SELECT name, street, city FROM Customer;
The above is a simplified case where you'd only move some data into a single new table.
A more complex (and more general) case is where you want to...
Separate your original table's columns into several foreign tables, and
Have unique entries in the foreign tables (that's usually the reason why you'd refactor your table).
This adds some additional challenges:
You'll end up inserting into multiple tables before you can insert their rowids into the table with the referencing rowids. This requires storing the results of each INSERT's last_insert_rowid() into a temporary table.
If the value already exists in the foreign table, its rowid must be stored instead of the one from the (non-executed) insertion operation.
Here's a complete solution for this. It manages a database of music records, constisting of a song's name, album title and artist name.
-- Original table
CREATE TABLE [Song] (
[title] TEXT,
[album] TEXT,
[artist] TEXT
);
-- Refactored tables
CREATE TABLE [Song2] (
[title] TEXT,
[album_rowid] INTEGER,
[artist_rowid] INTEGER
);
CREATE TABLE [Album] (
[rowid] INTEGER PRIMARY KEY AUTOINCREMENT,
[title] TEXT UNIQUE
);
CREATE TABLE [Artist] (
[rowid] INTEGER PRIMARY KEY AUTOINCREMENT,
[name] TEXT UNIQUE
);
-- Fill with sample data
INSERT INTO Song VALUES ("Hunting Girl", "Songs From The Wood", "Jethro Tull");
INSERT INTO Song VALUES ("Acres Wild", "Heavy Horses", "Jethro Tull");
INSERT INTO Song VALUES ("Broadford Bazar", "Heavy Horses", "Jethro Tull");
INSERT INTO Song VALUES ("Statue of Liberty", "White Music", "XTC");
INSERT INTO Song VALUES ("Standing In For Joe", "Wasp Star", "XTC");
INSERT INTO Song VALUES ("Velvet Green", "Songs From The Wood", "Jethro Tull");
-- Conversion starts here
CREATE TEMP TABLE [TempRowIDs] (
[album_id] INTEGER,
[artist_id] INTEGER
);
CREATE VIEW Song1 (title, album, artist) AS
SELECT Song2.title, Album.title, Artist.name
FROM Song2
JOIN Album ON (Song2.album_rowid == Album.rowid)
JOIN Artist ON (Song2.artist_rowid == Artist.rowid);
CREATE TEMP TRIGGER TempTrig INSTEAD OF INSERT ON Song1 FOR EACH ROW BEGIN
INSERT OR IGNORE INTO Album (title) SELECT NEW.album;
UPDATE TempRowIDs SET album_id = (SELECT COALESCE (
(SELECT rowid FROM Album WHERE changes()==0 AND title==NEW.album), last_insert_rowid()
) ) WHERE rowid==1;
INSERT OR IGNORE INTO Artist (name) SELECT NEW.artist;
UPDATE TempRowIDs SET artist_id = (SELECT COALESCE (
(SELECT rowid FROM Artist WHERE changes()==0 AND name==NEW.artist), last_insert_rowid()
) ) WHERE rowid==1;
INSERT INTO Song2 (title, album_rowid, artist_rowid) SELECT
NEW.title, (SELECT album_id FROM TempRowIDs), (SELECT artist_id FROM TempRowIDs);
END;
INSERT INTO TempRowIDs DEFAULT VALUES;
INSERT INTO Song1 (title, album, artist) SELECT title, album, artist FROM Song;
DROP TRIGGER TempTrig;
DROP TABLE TempRowIDs;
-- Conversion ends here
-- Print results
SELECT * FROM Song;
SELECT * FROM Song1;
-- Check if original and copy are identical (https://stackoverflow.com/a/13865679/43615)
SELECT CASE WHEN (SELECT COUNT(*) FROM (SELECT * FROM Song UNION SELECT * FROM Song1)) == (SELECT COUNT() FROM Song) THEN 'Success' ELSE 'Failure' END;
Note that this example has one potential issue: If the constraints on the foreign table are more complex, the SELECT rowid FROM search for the existing entry needs to be updated accordingly. Ideally, SQLite should provide a way to determine the conflicting rowid somehow, but it doesn't, unfortunately (see this related question).
Simple solution without triggers:
create VEHICLES_TEMP table including the CAR_ID
create your new CARS table without the VEHICLES columns you don't want
update CARS with VEHICLE_ID taken from VEHICLES_TEMP (identified by the CAR_ID)
create final VEHICLES table without the CAR_ID
Create a table New_Cars and a INSTEAD OF INSERT trigger, which will insert data to both tables Vehicles and Cars. When inserting to Cars, you can use last_insert_rowid() function to refer to inserted row in Vehicles table.
This can be temporary solution, or you can leave it in your database for further modifications.