I need to insert records into a production table. The problem is that one of the fields needs to be the same value as the primary key.
In the example below, the Insert query is dropping '99' into [AlsoMyID]. But that's just a placeholder. It needs to be whatever value is going into [MyID].
How do I write the Insert query so that the system will add the same PK value to both [MyID] and [AlsoMyID]?
Drop table #mylittletable
Create table #Mylittletable (
[MyID] int IDENTITY(1,1) NOT FOR REPLICATION NOT NULL,
[AlsoMyID] int,
[ActualData] varchar(1))
Select * from #Mylittletable
Insert into #Mylittletable values (99,'x')
Select * from #Mylittletable
If you're interested in the background, the developer is using AlsoMyID as a linking field so any number of records can be linked together using the original primary key value. That said, I have no control over the table structure.
Firstly, you cannot specify the value for identity column unless you use set identity_insert on. so according to your requirement, you need to insert the same value to AlsoMyID as MyID.
You can work it out as flowing:
insert into Mylittletable
select ##IDENTITY+1,'1'
With this trigger on the table you can insert anything on the alsoMyID-column and that will be overwritten with what get's set in the myID-column.
create trigger tr_Mylittletable ON Mylittletable
AFTER INSERT AS
BEGIN
declare #ID int = (select MyID from inserted)
update Mylittletable set AlsoMyID = #ID where MyID = #ID
END
NOTE: This only works when making inserts of one line at a time!
Related
i have two table userGold and AspNetUserRoles(UserId,RoleId) .
primary key type of UserGold is nvarchar(450)
same for AspNetUserRole.
my problem is that i want to get the last inserted primary key in UsereGold and insert it in AspNetUserRoles table using a trigger.
SCOPE_IDENTITY didn't work cause my primary key type is nvarchar.
i don't know what to do.
i saw solution like output inserted but it didn't work
create trigger addrole
on UserGold
after Insert
as
Begin
declare
#userid nvarchar(450)
set #userid=CAST(SCOPE_IDENTITY() AS nvarchar(450))
insert into AspNetUserRoles(UserId,RoleId)
values(#userid,'2c258e8d-c648-4b38-9b01-989d4dd525fe')
end
You should not write triggers - or anything else in a database - that only expect a single row to change. Databases work with sets of information, not single "records". Imagine what happens if someone create 5 rows in UserGold in a single insert statement. You can't put 5 userid values into a single #userId variable.
What you want is something like
-- assuming your tables are in the dbo schema! Make sure you include the schema name
create trigger AddDefaultRole on dbo.UserGold after insert as begin
set nocount on;
insert dbo.AspNetUserRoles (UserId, RoleId)
select UserId, '2c258e8d-c648-4b38-9b01-989d4dd525fe'
from inserted;
end
For more information, see Inserted and Deleted tables for triggers
I have one table called [FridgeTemperture], when any record inserted it should add one value in the new table MpSensors. But records are not being inserted in the new table when a record is inserted.
Error
Explicit value must be specified for identity column in table
'MpSensors' either identity_insert is set to ON or when a replication
user is inserting into a not for replication identity column.
CREATE TRIGGER [dbo].[FridgeTemperature_INSERT]
ON [dbo].[FridgeTemperture]
AFTER INSERT
AS
BEGIN
SET IDENTITY_INSERT MpSensors ON;
SET NOCOUNT ON;
DECLARE #fridge_temp varchar(10)
INSERT INTO MpSensors(fridge_temp)
VALUES(#fridge_temp)
SET IDENTITY_INSERT MpSensors OFF;
END
GO
table schema
CREATE TABLE [dbo].[MpSensors](
[id] [int] IDENTITY(1,1) NOT NULL,
[fridge_temp] [varchar](10) NULL
) ON [PRIMARY]
CREATE TABLE [dbo].[FridgeTemperture](
[Id] [int] IDENTITY(1,1) NOT NULL,
[ShopId] [nvarchar](4) NULL,
[Fridgetemp] [decimal](4, 2) NOT NULL,
[UpdatedDate] [datetime2](7) NOT NULL
GO
You don't need the set identity_insert on if you are not attempting to insert values to the identity column. Also, your current insert statement, if you loose the set identity_insert, will simply inside a single null row for any insert statement completed successfully on the FridgeTemperture table.
When using triggers, you have access to the records effected by the statement that fired the trigger via the auto-generated tables called inserted and deleted.
I think you are after something like this:
CREATE TRIGGER [dbo].[FridgeTemperature_INSERT]
ON [dbo].[FridgeTemperture]
AFTER INSERT
AS
BEGIN
INSERT INTO MpSensors(fridge_temp)
SELECT CAST(Fridgetemp as varchar(10))
FROM inserted
END
Though I can't really see any benefit of storing the same value in two different places, and in two different data types.
Update
Following our conversation in the comments, you can simply use an update statement in the trigger instead of an insert statement:
UPDATE MpSensors
SET fridge_temp = (
SELECT TOP 1 CAST(Fridgetemp as varchar(10))
FROM inserted
ORDER BY Id DESC
)
This should give you the latest record in case you have an insert statement that inserts more than a single record into the FridgeTemperture table in a single statement.
create TRIGGER [dbo].[FridgeTemperature_INSERT]
ON [dbo].[FridgeTemperture]
AFTER INSERT
AS
BEGIN
UPDATE MpSensors
SET fridge_temp = CAST(Fridgetemp as varchar(10))
FROM inserted
END
You need to use Select statement with CAST as [fridge_temp] is varchar in MpSensors table in Trigger. Try like this:
CREATE trigger <table_name>
ON <table_name>
AFTER Insert
AS
BEGIN
INSERT INTO <table_name>(column_name)
Select CAST(column_name as varchar(10))
FROM inserted
END
The inserted table stores copies of the affected rows during INSERT and UPDATE statements. During an insert or update transaction, new rows are added to both the inserted table and the trigger table. The rows in the inserted table are copies of the new rows in the trigger table.
How could I set a constraint on a table so that only one of the records has its isDefault bit field set to 1?
The constraint is not table scope, but one default per set of rows, specified by a FormID.
Use a unique filtered index
On SQL Server 2008 or higher you can simply use a unique filtered index
CREATE UNIQUE INDEX IX_TableName_FormID_isDefault
ON TableName(FormID)
WHERE isDefault = 1
Where the table is
CREATE TABLE TableName(
FormID INT NOT NULL,
isDefault BIT NOT NULL
)
For example if you try to insert many rows with the same FormID and isDefault set to 1 you will have this error:
Cannot insert duplicate key row in object 'dbo.TableName' with unique
index 'IX_TableName_FormID_isDefault'. The duplicate key value is (1).
Source: http://technet.microsoft.com/en-us/library/cc280372.aspx
Here's a modification of Damien_The_Unbeliever's solution that allows one default per FormID.
CREATE VIEW form_defaults
AS
SELECT FormID
FROM whatever
WHERE isDefault = 1
GO
CREATE UNIQUE CLUSTERED INDEX ix_form_defaults on form_defaults (FormID)
GO
But the serious relational folks will tell you this information should just be in another table.
CREATE TABLE form
FormID int NOT NULL PRIMARY KEY
DefaultWhateverID int FOREIGN KEY REFERENCES Whatever(ID)
From a normalization perspective, this would be an inefficient way of storing a single fact.
I would opt to hold this information at a higher level, by storing (in a different table) a foreign key to the identifier of the row which is considered to be the default.
CREATE TABLE [dbo].[Foo](
[Id] [int] NOT NULL,
CONSTRAINT [PK_Foo] PRIMARY KEY CLUSTERED
(
[Id] ASC
) ON [PRIMARY]
) ON [PRIMARY]
GO
CREATE TABLE [dbo].[DefaultSettings](
[DefaultFoo] [int] NULL
) ON [PRIMARY]
GO
ALTER TABLE [dbo].[DefaultSettings] WITH CHECK ADD CONSTRAINT [FK_DefaultSettings_Foo] FOREIGN KEY([DefaultFoo])
REFERENCES [dbo].[Foo] ([Id])
GO
ALTER TABLE [dbo].[DefaultSettings] CHECK CONSTRAINT [FK_DefaultSettings_Foo]
GO
You could use an insert/update trigger.
Within the trigger after an insert or update, if the count of rows with isDefault = 1 is more than 1, then rollback the transaction.
CREATE VIEW vOnlyOneDefault
AS
SELECT 1 as Lock
FROM <underlying table>
WHERE Default = 1
GO
CREATE UNIQUE CLUSTERED INDEX IX_vOnlyOneDefault on vOnlyOneDefault (Lock)
GO
You'll need to have the right ANSI settings turned on for this.
I don't know about SQLServer.But if it supports Function-Based Indexes like in Oracle, I hope this can be translated, if not, sorry.
You can do an index like this on suposed that default value is 1234, the column is DEFAULT_COLUMN and ID_COLUMN is the primary key:
CREATE
UNIQUE
INDEX only_one_default
ON my_table
( DECODE(DEFAULT_COLUMN, 1234, -1, ID_COLUMN) )
This DDL creates an unique index indexing -1 if the value of DEFAULT_COLUMN is 1234 and ID_COLUMN in any other case. Then, if two columns have DEFAULT_COLUMN value, it raises an exception.
The question implies to me that you have a primary table that has some child records and one of those child records will be the default record. Using address and a separate default table here is an example of how to make that happen using third normal form. Of course I don't know if it's valuable to answer something that is so old but it struck my fancy.
--drop table dev.defaultAddress;
--drop table dev.addresses;
--drop table dev.people;
CREATE TABLE [dev].[people](
[Id] [int] identity primary key,
name char(20)
)
GO
CREATE TABLE [dev].[Addresses](
id int identity primary key,
peopleId int foreign key references dev.people(id),
address varchar(100)
) ON [PRIMARY]
GO
CREATE TABLE [dev].[defaultAddress](
id int identity primary key,
peopleId int foreign key references dev.people(id),
addressesId int foreign key references dev.addresses(id))
go
create unique index defaultAddress on dev.defaultAddress (peopleId)
go
create unique index idx_addr_id_person on dev.addresses(peopleid,id);
go
ALTER TABLE dev.defaultAddress
ADD CONSTRAINT FK_Def_People_Address
FOREIGN KEY(peopleID, addressesID)
REFERENCES dev.Addresses(peopleId, id)
go
insert into dev.people (name)
select 'Bill' union
select 'John' union
select 'Harry'
insert into dev.Addresses (peopleid, address)
select 1, '123 someplace' union
select 1,'work place' union
select 2,'home address' union
select 3,'some address'
insert into dev.defaultaddress (peopleId, addressesid)
select 1,1 union
select 2,3
-- so two home addresses are default now
-- try adding another default address to Bill and you get an error
select * from dev.people
join dev.addresses on people.id = addresses.peopleid
left join dev.defaultAddress on defaultAddress.peopleid = people.id and defaultaddress.addressesid = addresses.id
insert into dev.defaultaddress (peopleId, addressesId)
select 1,2
GO
You could do it through an instead of trigger, or if you want it as a constraint create a constraint that references a function that checks for a row that has the default set to 1
EDIT oops, needs to be <=
Create table mytable(id1 int, defaultX bit not null default(0))
go
create Function dbo.fx_DefaultExists()
returns int as
Begin
Declare #Ret int
Set #ret = 0
Select #ret = count(1) from mytable
Where defaultX = 1
Return #ret
End
GO
Alter table mytable add
CONSTRAINT [CHK_DEFAULT_SET] CHECK
(([dbo].fx_DefaultExists()<=(1)))
GO
Insert into mytable (id1, defaultX) values (1,1)
Insert into mytable (id1, defaultX) values (2,1)
This is a fairly complex process that cannot be handled through a simple constraint.
We do this through a trigger. However before you write the trigger you need to be able to answer several things:
do we want to fail the insert if a default exists, change it to 0 instead of 1 or change the existing default to 0 and leave this one as 1?
what do we want to do if the default record is deleted and other non default records are still there? Do we make one the default, if so how do we determine which one?
You will also need to be very, very careful to make the trigger handle multiple row processing. For instance a client might decide that all of the records of a particular type should be the default. You wouldn't change a million records one at a time, so this trigger needs to be able to handle that. It also needs to handle that without looping or the use of a cursor (you really don't want the type of transaction discussed above to take hours locking up the table the whole time).
You also need a very extensive tesing scenario for this trigger before it goes live. You need to test:
adding a record with no default and it is the first record for that customer
adding a record with a default and it is the first record for that customer
adding a record with no default and it is the not the first record for that customer
adding a record with a default and it is the not the first record for that customer
Updating a record to have the default when no other record has it (assuming you don't require one record to always be set as the deafault)
Updating a record to remove the default
Deleting the record with the deafult
Deleting a record without the default
Performing a mass insert with multiple situations in the data including two records which both have isdefault set to 1 and all of the situations tested when running individual record inserts
Performing a mass update with multiple situations in the data including two records which both have isdefault set to 1 and all of the situations tested when running individual record updates
Performing a mass delete with multiple situations in the data including two records which both have isdefault set to 1 and all of the situations tested when running individual record deletes
#Andy Jones gave an answer above closest to mine, but bearing in mind the Rule of Three, I placed the logic directly in the stored proc that updates this table. This was my simple solution. If I need to update the table from elsewhere, I will move the logic to a trigger. The one default rule applies to each set of records specified by a FormID and a ConfigID:
ALTER proc [dbo].[cpForm_UpdateLinkedReport]
#reportLinkId int,
#defaultYN bit,
#linkName nvarchar(150)
as
if #defaultYN = 1
begin
declare #formId int, #configId int
select #formId = FormID, #configId = ConfigID from csReportLink where ReportLinkID = #reportLinkId
update csReportLink set DefaultYN = 0 where isnull(ConfigID, #configId) = #configId and FormID = #formId
end
update
csReportLink
set
DefaultYN = #defaultYN,
LinkName = #linkName
where
ReportLinkID = #reportLinkId
(forgive me - I'm new to both StackOverflow & SQL)
Tl;dr - When using ##identity (or any other option such as scope_identity or output variable), is it possible to also use a view? Here is an example of a stored procedure using ##identity:
--SNIP--
DECLARE #AID INT
DECLARE #BID INT
INSERT INTO dbo.A (oct1)
VALUES
(#oct1)
SELECT #AID = ##IDENTITY;
INSERT INTO dbo.B (duo1)
VALUES
(#duo2)
SELECT #BID = ##IDENTITY
INSERT INTO dbo.tblAB (AID, BID)
VALUES
(#AID, #BID)
GO
Longer:
When inserting into a table, you can capture the current value of the identity seed using ##identity. This is useful if you want to insert into table A and B, capture the identity value, then insert into table AB relating A to B. Obviously this is for purposes of data normalization.
Let's say you were to abstract the DB Schema with a few that performs inner joins on your tables to make the data easier to work with. How would you populate the cross reference tables properly in that case? Can it be done the same way, if so, how?
Avoid using ##IDENTITY or SCOPE_IDENTITY() if your system is using Parallel plans as there is a nasty bug. Please refer -
http://connect.microsoft.com/SQL/feedback/ViewFeedback.aspx?FeedbackID=328811
Better way to fetch the inserted Identity ID would be to use OUTPUT clause.
CREATE TABLE tblTest
(
Sno INT IDENTITY(1,1) NOT NULL,
FirstName VARCHAR(20)
)
DECLARE #pk TABLE (ID INT)
INSERT INTO tblTest(FirstName)
OUTPUT INSERTED.Sno INTO #pk
SELECT 'sample'
SELECT * FROM #pk
EDIT:
It would work with Views as well. Please see the sample below. Hope this is what you were looking for.
CREATE VIEW v1
AS
SELECT sno, firstname FROM tbltest
GO
DECLARE #pk TABLE (ID INT)
INSERT INTO v1(FirstName)
OUTPUT INSERTED.Sno INTO #pk
SELECT 'sample'
SELECT ID FROM #pk
##IDENTITY returns the last IDENTITY value produced on a connection, regardless of the table that produced the value, and regardless of the scope of the statement that produced the value.
SCOPE_IDENTITY() returns the last IDENTITY value produced on a connection and by a statement in the same scope, regardless of the table that produced the value. SCOPE_IDENTITY(), like ##IDENTITY, will return the last identity value created in the current session, but it will also limit it to your current scope as well
Although the issue with either of these is fixed by microsoft , I would suggest you should go with "OUTPUT", and yes, it can be used with view as well
I have a simple details table like so:
listid
custid
status
last_changed
The primary key consists of both listid and custid.
Now I'm trying to setup a trigger that sets the last_changed column to the current datetime every time an insert or update happens. I've found lots of info on how to do that with a single PK column, but with multiple PKs it gets confusing on how to correctly specify the PKs from the INSERTED table.
The trigger has to work in SQL Server 2005/2008/R2.
Thanks for a working trigger code!
Bonus would be to also check if the data was actually altered and only update last_changed in that case but for the sake of actually understanding how to correctly code the main question I'd like to see this as a separate code block if at all.
Hmm.... just because the primary key is made up of two columns shouldn't really make a big difference....
CREATE TRIGGER dbo.trgAfterUpdate ON dbo.YourTable
AFTER INSERT, UPDATE
AS
UPDATE dbo.YourTable
SET last_changed = GETDATE()
FROM Inserted i
WHERE dbo.YourTable.listid = i.listid AND dbo.YourTable.custid = i.custid
You just need to establish the JOIN between the two tables (your own data table and the Inserted pseudo table) on both columns...
Are am I missing something?? .....
CREATE TRIGGER dbo.trgAfterUpdate ON dbo.YourTable
AFTER INSERT, UPDATE
AS
UPDATE dbo.YourTable
SET last_changed = GETDATE()
FROM Inserted i
JOIN dbo.YourTable.listid = i.listid AND dbo.YourTable.custid = i.custid
WHERE NOT EXISTS
(SELECT 1 FROM Deleted D Where D.listid=I.listid AND D.custid=i.custid AND (D.status=i.status)
Here i assuming that stasus column is not nullable. If yes, you should add additional code to check if one of columns is NULL
You can check every field in trigger by comparing data from inserted and deleted table like below :
CREATE TRIGGER [dbo].[tr_test] ON [dbo].[table]
AFTER INSERT, UPDATE
AS
BEGIN
DECLARE #old_listid INT
DECLARE #old_custid INT
DECLARE #old_status INT
DECLARE #new_listid INT
DECLARE #new_custid INT
DECLARE #new_status INT
SELECT #old_listid=[listid], #old_custid=[custid], #old_status = [status] FROM [deleted]
SELECT #new_listid=[listid], #new_custid=[custid], #new_status = [status] FROM [inserted]
IF #oldstatus <> #new_status
BEGIN
UPDATE TABLE table SET last_changed = GETDATE() WHERE [listid] = #new_listid AND [custid] = #new_custid
END
END