How can I use an auto-generated column to populate another column during an INSERT statement?
Long story short: we are reusing a database table and an related ASP page to display completely different data than was originally intended.
I have a table similar in structure to the following. It's structure is out of my control.
ID int NON-NULL, IDENTITY(1,1)
OrderNo varchar(50) NON-NULL, UNIQUE
More ...
The table has been repurposed and we are not using the OrderNo column. However, it's NON-NULL and UNIQUE. As dummy data, I want to populate it with the row's ID column.
I have the following SQL so far, but can't work out how to use the row's generated ID.
INSERT INTO MyTable (OrderNo, More)
OUTPUT INSERTED.ID
VALUES (CAST(ID AS varchar(50)))
This just gives:
Msg 207, Level 16, State 1, Line 3
Invalid column name 'ID'.
Here's a solution using the OUTPUT clause. Unfortunately, you won't be able to do it in a single statement.
CREATE TABLE Orders (
ID int not null identity(1,1),
OrderNo varchar(50) not null unique
)
CREATE TABLE #NewIDs ( ID int )
INSERT Orders (OrderNo)
OUTPUT INSERTED.ID INTO #NewIDs
SELECT 12345
UPDATE o
SET o.OrderNo = i.ID
FROM Orders o
JOIN #NewIDs i
ON i.ID = o.ID
SELECT * FROM Orders
One option would be:
create trigger YourTable_Trigger
on YourTable
INSTEAD OF INSERT
as begin
INSERT INTO YourTable (OrderNo, AnotherField)
SELECT 0, AnotherField FROM Inserted
UPDATE YourTable SET OrderNo = SCOPE_IDENTITY() WHERE ID = SCOPE_IDENTITY()
end;
And here is the Fiddle.
Good luck.
Related
I have a table, let's call it A. I want to delete rows with IDs 1 and 2 from that table. For that, I created a table variable #B, containing values 1 and 2 but that column I will name PK.
Now I do this:
DELETE FROM A
WHERE ID IN (
SELECT ID
FROM #B
)
Notice my (deliberate) programming error. In the sub-select, I have used a wrong column name. Accidentally it is the same name used in table A.
This should result in an 'invalid column name' error, right? Except it does not. It executes. Not only that, all data from table A gets deleted. As if there is no more predicate.
I have created a full demo script:
-- What happened to my data???
IF OBJECT_ID('tempdb..#JustATable') IS NOT NULL
DROP TABLE #JustATable
CREATE TABLE #JustATable (
PK INT NOT NULL PRIMARY KEY IDENTITY(1, 1),
ID INT NOT NULL,
NOTE VARCHAR(100) NOT NULL
)
INSERT INTO #JustATable (ID, NOTE)
SELECT database_id, DB_NAME(database_id)
FROM sys.databases;
SELECT NULL [inserted all the rows from sys.databases into the temptable], *
FROM #JustATable;
DECLARE #JustATableVariable TABLE (
PK INT NOT NULL PRIMARY KEY IDENTITY(1, 1),
ID_2 INT NOT NULL,
NOTE VARCHAR(100) NOT NULL
)
INSERT INTO #JustATableVariable (ID_2, NOTE)
SELECT database_id, DB_NAME(database_id)
FROM sys.databases
WHERE database_id = 2;
SELECT NULL [this is my table variable data], *
FROM #JustATableVariable;
DELETE FROM #JustATable
WHERE ID IN (
SELECT ID_2
FROM #JustATableVariable
);
SELECT NULL [I have just removed tempdb from the temptable], *
FROM #JustATable;
DELETE FROM #JustATable
WHERE ID IN (
SELECT ID /* this is the wrong column name but the same name as used in the temptable column */
FROM #JustATableVariable
);
SELECT NULL [wait...where is my data?], *
FROM #JustATable;
Can someone explain to me what is going on here? Has anyone seen this behavior before? Could this be a bug?
In the subquery ... (select id from #b) the column id is not fully qualified. So according to SQL specs, the RDBMS will first see if id column exists in table #b. If it does not, it will search "upwards" until it finds the id column in table a. The query is effectively identical to:
delete from a where id in (select a.id from #b)
Syntactically correct, semantically wrong.
I found following link to assign identical ID to duplicates in SQL server,
my understanding there is no sql server function to automatically generate it rather than using insert and update queries in link attached, is that statement True, if yes, then what would be the trigger if for example someone insert data to MyTable then run insert and update query from link:
Assign identical ID to duplicates in SQL server
INSERT INTO secondTable (word) SELECT distinct word FROM MyTable;
UPDATE MyTable SET ID = (SELECT id from secondTable where MyTable.word = secondTable.word)
thanks,
S
Is this what you want? I can't think of an "automatic" solution that would just increase the Id for new words.
CREATE TABLE MyTable (
Id INT NOT NULL,
Word NVARCHAR(255) NOT NULL
PRIMARY KEY (Id, Word)); -- primary key will make it impossible to have more than one combination of word and id
DECLARE #word NVARCHAR(255) = 'Hello!';
-- Get existing id or calculate a new id
DECLARE #Id INT = (SELECT Id FROM MyTable WHERE Word = #word);
IF(#id IS NULL) SET #Id = (SELECT MAX(Id) + 1 FROM MyTable);
INSERT INTO MyTable (Id, Word)
VALUES (#id, #word)
SELECT * FROM MyTable
If you can't for some reason have id and word as a combined primary key, you may use an unique index to make sure that there is only one combination
I have table of transaction which contains a column transactionId that has values like |H000021|B1|.
I need to make a join with table Category which has a column CategoryID with values like H000021.
I cannot apply join unless data is same.
So I want to split or remove the unnecessary data contained in TransctionId so that I can join both tables.
Kindly help me with the solutions.
Create a computed column with the code only.
Initial scenario:
create table Transactions
(
transactionId varchar(12) primary key,
whatever varchar(100)
)
create table Category
(
transactionId varchar(7) primary key,
name varchar(100)
)
insert into Transactions
select'|H000021|B1|', 'Anything'
insert into Category
select 'H000021', 'A category'
Add computed column:
alter table Transactions add transactionId_code as substring(transactionid, 2, 7) persisted
Join using the new computed column:
select *
from Transactions t
inner join Category c on t.transactionId_code = c.transactionId
Get a straighforward query plan:
You should fix your data so the columns are the same. But sometimes we are stuck with other people's bad design decisions. In particular, the transaction data should contain a column for the category -- even if the category is part of the id.
In any case:
select . . .
from transaction t join
category c
on transactionid like '|' + categoryid + |%';
Or if the category id is always 7 characters:
select . . .
from transaction t join
category c
on categoryid = substring(transactionid, 2, 7)
You can do this using query :
CREATE TABLE #MyTable
(PrimaryKey int PRIMARY KEY,
KeyTransacFull varchar(50)
);
GO
CREATE TABLE #MyTransaction
(PrimaryKey int PRIMARY KEY,
KeyTransac varchar(50)
);
GO
INSERT INTO #MyTable
SELECT 1, '|H000021|B1|'
INSERT INTO #MyTable
SELECT 2, '|H000021|B1|'
INSERT INTO #MyTransaction
SELECT 1, 'H000021'
SELECT * FROM #MyTable
SELECT * FROM #MyTransaction
SELECT *
FROM #MyTable
JOIN #MyTransaction ON KeyTransacFull LIKE '|'+KeyTransac+'|%'
DROP TABLE #MyTable
DROP TABLE #MyTransaction
Can someone help explain this to me and resolve it?
http://sqlfiddle.com/#!6/2adc7/9
The INSERT statement conflicted with the FOREIGN KEY constraint "FK_tblMobileForms_tblForms". The conflict occurred in database "db_6_2adc7", table "dbo.tblForms", column 'fm_id'.: insert into tblMobileForms(fm_name) values ('lol')
My schema has the ID from tblMobileForms be a foreign key to tblForms.fm_id
To do what you are trying to do you cannot set up the FK on tblMobileForms as an identity. See my fiddle below for more information.
http://sqlfiddle.com/#!6/be6f7/2
Alternatively what you could do is to have tblMobileForms have it's own separate surrogate key and have a different FK column to the tblForms table.
The PK on the tblMobileForms table has the same name as the FK on the same table. Seeing the PK is an IDENTITY column, you can end up with non-matching values.
In my fiddle, the tblForms table contained IDs in the upper 60s. Running the INSERT in the child table would add a record with id 1, which does not exist in the parent table.
I'd create a new row in the tblMobileForms table, and reference that to the parent table.
You could use an INSTEAD OF trigger to apply a random ID to each mobile form as it is inserted:
CREATE TRIGGER dbo.tblMobileForms_Insert
ON dbo.tblMobileForms
INSTEAD OF INSERT
AS
BEGIN
DECLARE #Inserted TABLE (fm_ID INT, fm_html_file VARBINARY(MAX), fm_name NVARCHAR(50));
INSERT #Inserted (fm_ID, fm_html_File, fm_Name)
SELECT fm_ID, fm_html_File, fm_Name
FROM inserted;
IF EXISTS (SELECT 1 FROM #Inserted WHERE fm_ID IS NULL)
BEGIN
WITH NewRows AS
( SELECT fm_ID, fm_html_File, fm_Name, RowNumber = ROW_NUMBER() OVER (ORDER BY fm_name)
FROM #Inserted
WHERE fm_ID IS NULL
), AvailableIDs AS
( SELECT fm_ID, RowNumber = ROW_NUMBER() OVER (ORDER BY fm_ID)
FROM tblForms f
WHERE NOT EXISTS
( SELECT 1
FROM tblMobileForms m
WHERE f.Fm_ID = m.fm_ID
)
AND NOT EXISTS
( SELECT 1
FROM inserted i
WHERE f.fm_ID = i.fm_ID
)
)
UPDATE NewRows
SET fm_ID = a.fm_ID
FROM NewRows n
INNER JOIN AvailableIDs a
ON a.RowNumber = n.RowNumber
IF EXISTS (SELECT 1 FROM #Inserted WHERE fm_ID IS NULL)
BEGIN
RAISERROR ('Not enough free Form IDs to allocate an ID to the inserted rows', 16, 1);
RETURN;
END
END
INSERT dbo.tblMobileForms (fm_ID, fm_html_File, fm_Name)
SELECT fm_ID, fm_html_file, fm_name
FROM #Inserted
END
When each row is inserted the trigger will check for the next available ID in tblForms and apply it sequentially to the inserted rows where fm_id is not specified. If there are no free ID's in tblForms then the trigger will throw an error so a 1 to 1 relationship is maintained (The error would be thrown anyway since tblMobileForms.fm_id is also a PK).
N.b. this requires tblForms.fm_ID to just be an int column, and not identity.
I'm writing a SQL script to generate test data for our database. I'm generating the data in table variables (so I can track it later) and then inserting it into the real tables. The problem is, I need to track which rows I've added to the parent table, so that I can generate its child data later on in the script. For example:
CREATE TABLE Customer (
CustomerId INT IDENTITY,
Name VARCHAR(50)
)
CREATE TABLE Order (
OrderId INT IDENTITY,
CustomerId INT,
Product VARCHAR(50)
)
So, in my script, I create equivalent table variables:
DECLARE #Customer TABLE (
CustomerId INT IDENTITY,
Name VARCHAR(50)
) -- populate customers
DECLARE #Order TABLE (
OrderId INT IDENTITY,
CustomerId INT,
Product VARCHAR(50)
) -- populate orders
And I generate and insert sample data into each table variable.
Now, when I go to insert customers from my table variable into the real table, the CustomerId column in the table variable will become meaningless, as the real table has its own identity seed for its CustomerId column.
Is there a way I can track the new identity of each row inserted into the real table, in my table variable, so I can use a proper CustomerId for the order records? Or, is there a better way I should be going about this?
(Note: I originally started with an application to generate the test data, but it ran too slow during insert as > 1,000,000 records need to be generated.)
WHy do you need identity values on the table variables? If you use just int, you can isnert the ids after the insert is done. Grab them using the output clause. YOu might need an input values and an output values table varaiable to get this just right like this:
DECLARE #CustomerInputs TABLE (Name VARCHAR(50) )
DECLARE #CustomerOutputs TABLE (CustomerId INT ,Name VARCHAR(50) )
INSERT INTO CUSTOMERS (name)
OUTPUT inserted.Customerid, inserted.Name INTO #CustomerOutputs
SELECT Name FROM #CustomerInputs
SELECT * from #CustomerOutputs
You can insert the data to the table with a cursor and use the built-in function SCOPE_IDENTITY() to get the last id which was inserted in the current scope (by your script).
See this MSDN article for more information on SCOPE_IDENTITY.
Here is one way of doing it. If you can use it depends on your situation. You should not do it in production environment when users use your db.
-- Get the next identity values for Customer and Order
declare #NextCustomerID int
declare #NextOrderID int
set #NextCustomerID = IDENT_CURRENT('Customer')+1
set #NextOrderID = IDENT_CURRENT('Order')+1
-- Create tmp tables
create table #Customer (CustomerID int identity, Name varchar(50))
create table #Order (OrderID int identity, CustomerID int, Product varchar(50))
-- Reseed the identity columns in temp tables
dbcc checkident(#Customer, reseed, #NextCustomerID)
dbcc checkident(#Order, reseed, #NextOrderID)
-- Populate #Customer
-- Populate #Order
-- Allow insert to identity column on Customer
set identity_insert Customer on
-- Add rows to Customer
insert into Customer(CustomerId, Name)
select CustomerID, Name
from #Customer
-- Restore identity functionality on Customer
set identity_insert Customer off
-- Add rows to Order
set identity_insert [Order] on
insert into [Order](OrderID, CustomerID, Product)
select OrderID, CustomerID, Product
from #Order
set identity_insert [Order] off
-- Drop temp tables
drop table #Customer
drop table #Order
-- Check result
select * from [Order]
select * from Customer
The way I'd do it its first obtain the MAX(CustomerId) from your Customer Table. Then I'd get rid of the IDENTITY column on your variable table and do my own CustomerId using ROW_NUMBER() and the MaxCustomerId. It should be something like this:
DECLARE #MaxCustomerId INT
SELECT #MaxCustomerId = ISNULL(MAX(CustomerId),0)
FROM Customer
DECLARE #Customer TABLE (
CustomerId INT,
Name VARCHAR(50)
)
INSERT INTO #Customer(CustomerId, Name)
SELECT #MaxCustomerId + ROW_NUMBER() OVER(ORDER BY SomeColumn), Name
FROM YourDataTable
Or insert the values on a temp table, so you can use the same ids to fill your Order table.