Dear
i already create one table for employee information with ASP.net interface
now i show add one operation in my table as below,
i have four columns( WorkDatey,WorkDatem,WorkDated,absentday) all the columns from integer type in table name employee.
now i should add new column (realworkdays) and the result here should be automatic save after entering previous data as example:
WorkDatey= 2011 ,
WorkDatem= 2 ,
WorkDated=14 ,
absentday=6
the operation should be : (2011*365)+(2*30)+(14)-(6) and result will store in column (realworkdays).
i already try it as trigger but i have some thing wrong:
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TRIGGER daysResult
ON [dbo].[employee]
AFTER insert
As
DECLARE #realworkdays int
BEGIN
SET NOCOUNT ON;
select WorkDatey,WorkDatem,WorkDated,absent from [dbo].[employee]
#realworkdays= (workdatey*350)+(workdatem*29)+(workdated)-(absent)
insert into [dbo].[employee] (totaldays)values (#realworkdays)
END
GO
Since you are using sql server 2005, i would suggest you use a computed column
ALTER TABLE employee DROP COLUMN realworkdays;
ALTER TABLE employee ADD COLUMN realworkdays AS (
(WorkDatey * 365) +
(WorkDatem * 30) +
(WorkDated) -
(absentday)
)
You can add the PERSISTED so it will store the data, optionally indexing it.
On a side note, your trigger is inserted a new row, instead of updating the value of the current row.
You are supposed to update the inserted records, not insert new ones.
So, it should be the UPDATE statement, and you can do both the calculations and the updates in one go.
CREATE TRIGGER daysResult
ON [dbo].[employee]
AFTER insert
AS
BEGIN
UPDATE employee
SET realworkdays = (inserted.workdatey*350)+(inserted.workdatem*29)+
(inserted.workdated)-(inserted.absent)
FROM inserted
WHERE employee.ID = inserted.ID
END
Still it would be better to use a computed column, as #The Scrum Meister has suggested.
Related
I need to create a new DATETIME column in SQL Server that will always contain the date of when the record was created, and then it needs to automatically update whenever the record is modified. I've heard people say I need a trigger, which is fine, but I don't know how to write it. Could somebody help with the syntax for a trigger to accomplish this?
In MySQL terms, it should do exactly the same as this MySQL statement:
ADD `modstamp` timestamp NULL
DEFAULT CURRENT_TIMESTAMP on update CURRENT_TIMESTAMP
Here are a few requirements:
I can't alter my UPDATE statements to set the field when the row is modified, because I don't control the application logic that writes to the records.
Ideally, I would not need to know the names of any other columns in the table (such as the primary key)
It should be short and efficient, because it will happen very often.
SQL Server doesn't have a way to define a default value for UPDATE.
So you need to add a column with default value for inserting:
ADD modstamp DATETIME2 NULL DEFAULT GETDATE()
And add a trigger on that table:
CREATE TRIGGER tgr_modstamp
ON **TABLENAME**
AFTER UPDATE AS
UPDATE **TABLENAME**
SET ModStamp = GETDATE()
WHERE **ID** IN (SELECT DISTINCT **ID** FROM Inserted)
And yes, you need to specify a identity column for each trigger.
CAUTION: take care when inserting columns on tables where you don't know the code of the application. If your app have INSERT VALUES command without column definition, it will raise errors even with default value on new columns.
This is possible since SQL Server 2016 by using PERIOD FOR SYSTEM_TIME.
This is something that was introduced for temporal tables but you don't have to use temporal tables to use this.
An example is below
CREATE TABLE dbo.YourTable
(
FooId INT PRIMARY KEY CLUSTERED,
FooName VARCHAR(50) NOT NULL,
modstamp DATETIME2 GENERATED ALWAYS AS ROW START NOT NULL,
MaxDateTime2 DATETIME2 GENERATED ALWAYS AS ROW END HIDDEN NOT NULL,
PERIOD FOR SYSTEM_TIME (modstamp,MaxDateTime2)
)
INSERT INTO dbo.YourTable (FooId, FooName)
VALUES (1,'abc');
SELECT *
FROM dbo.YourTable;
WAITFOR DELAY '00:00:05'
UPDATE dbo.YourTable
SET FooName = 'xyz'
WHERE FooId = 1;
SELECT *
FROM dbo.YourTable;
DROP TABLE dbo.YourTable;
It has some limitations.
The time stored will be updated by the system and always be UTC.
There is a need to declare a second column (MaxDateTime2 above) that is completely superfluous for this use case. But it can be marked as hidden making it easier to ignore.
Okay, I always like to keep track of not only when something happened but who did it!
Lets create a test table in [tempdb] named [dwarfs]. At a prior job, a financial institution, we keep track of inserted (create) date and updated (modify) date.
-- just playing
use tempdb;
go
-- drop table
if object_id('dwarfs') > 0
drop table dwarfs
go
-- create table
create table dwarfs
(
asigned_id int identity(1,1),
full_name varchar(16),
ins_date datetime,
ins_name sysname,
upd_date datetime,
upd_name sysname,
);
go
-- insert/update dates
alter table dwarfs
add constraint [df_ins_date] default (getdate()) for ins_date;
alter table dwarfs
add constraint [df_upd_date] default (getdate()) for upd_date;
-- insert/update names
alter table dwarfs
add constraint [df_ins_name] default (coalesce(suser_sname(),'?')) for ins_name;
alter table dwarfs
add constraint [df_upd_name] default (coalesce(suser_sname(),'?')) for upd_name;
go
For updates, but the inserted and deleted tables exist. I choose to join on the inserted for the update.
-- create the update trigger
create trigger trg_changed_info on dbo.dwarfs
for update
as
begin
-- nothing to do?
if (##rowcount = 0)
return;
update d
set
upd_date = getdate(),
upd_name = (coalesce(suser_sname(),'?'))
from
dwarfs d join inserted i
on
d.asigned_id = i.asigned_id;
end
go
Last but not least, lets test the code. Anyone can type a untested TSQL statement in. However, I always stress testing to my team!
-- remove data
truncate table dwarfs;
go
-- add data
insert into dwarfs (full_name) values
('bilbo baggins'),
('gandalf the grey');
go
-- show the data
select * from dwarfs;
-- update data
update dwarfs
set full_name = 'gandalf'
where asigned_id = 2;
-- show the data
select * from dwarfs;
The output. I only waited 10 seconds between the insert and the delete. Nice thing is that who and when are both captured.
Create trigger tr_somename
On table_name
For update
As
Begin
Set nocount on;
Update t
Set t.field_name = getdate()
From table_name t inner join inserted I
On t.pk_column = I.pk_column
End
ALTER TRIGGER [trg_table_name_Modified]
ON [table_name]
AFTER UPDATE
AS
Begin
UPDATE table_name
SET modified_dt_tm = GETDATE() -- or use SYSDATETIME() for 2008 and newer
FROM Inserted i
WHERE i.ID = table_name.id
end
In my SQl Server I have a table of around 40 attributes/columns. There is a daily load which might update any of these columns. I want to capture the changes in these columns in a separate table with a reason code column telling which column value changed. There might be instances where more than one column value might get changed in a single daily load, in that case the changed log table should capture all these changes separately in rows with each row depicting the individual change.
For Example:
TableA(column1(pk),column2,column3,column4)
values(1,100,ABC,999)
After update:
TableA(column1(pk),column2,column3,column4)
values(1,100,ACD,901)
The corresponding change log table should have two entries:
TabChangeLog(column1,before,after,reason);
values(1,ABC,ACD,'column3 changed')
values(1,999,901,'column4 changed')
I tried implementing this through triggers but am not able to figure out a way to separate each of these changes in separate rows when there are more than one changes. Please help
You need to create a trigger like :
create trigger trigger_name
instead of update as
if update(column1)
begin
insert into TabChangeLog
select inserted.column1, inserted.column3, deleted.column3, 'column3', 'update/change'
from inserted i inner join deleted d
on i.column1 = d.column2
end
if update(column2)
begin
insert into TabChangeLog
select inserted.column1, inserted.column2, deleted.column2, 'column2', 'update/change'
from inserted i inner join deleted d
on i.column1 = d.column2
end
...
https://www.tutorialgateway.org/instead-of-update-triggers-in-sql-server/
Microsoft SQL Server 2016 has a thing called Temporal Tables which would probably simplify your job a lot. It lets you rewind a dataset through time to see the changes:
https://learn.microsoft.com/en-us/sql/relational-databases/tables/temporal-tables?view=sql-server-2017
If you don't want to go that route and use triggers instead. UPDATE triggers have two tables inserted and deleted that let you know what the row state was before and after.
*Edit: These are tables so you have to use SELECT INTO etc to interact with them you can't do conditional logic (if /else)
CREATE TABLE [dbo].[Table1](
[Id] [int] NOT NULL,
[Tail] [int] NOT NULL,
CONSTRAINT [PK_Table1_1] PRIMARY KEY CLUSTERED
(
[Id] ASC
)
)
CREATE TABLE Table1_Audit
(
Audit varchar(100)
)
--drop trigger Table1_OnUPDATE
CREATE TRIGGER Table1_OnUPDATE
ON dbo.Table1
AFTER UPDATE
AS
BEGIN
-- SET NOCOUNT ON added to prevent extra result sets from
-- interfering with SELECT statements.
SET NOCOUNT ON;
-- Insert statements for trigger here
INSERT INTO Table1_Audit ([Audit])
select CONCAT('Tail changed to' ,inserted.Tail,' for pk Id=',inserted.Id) from inserted inner join
deleted on inserted.Id = deleted.Id --pk must be the same
where
inserted.Tail <> deleted.Tail --field x must be different
END
GO
--truncate table Table1_Audit
--update Table1 set Tail = 5
select * from Table1_Audit
I m making a mistake somewhere but can't figure out.
Scenario is this:
Whenever a new row is inserted in table 'TestTrigger', the table TriggerInsert should get a value capturing time when a new row was inserted in TestTrigger.
The problem is, whenever the trigger hits, instead of just a new row, the whole table gets repopulated in TestTrigger, each time. I only want to capture, the new rows not the entire table getting inserted on each trigger.
Here is my trigger:
USE [irfaan]
GO
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
ALTER Trigger [dbo].[InsertTriggerTest] on [irfaan].[dbo].[TestTrigger]
--For Insert
After insert
as
INSERT into TriggerInsert (CurrTime, IOFNum) SELECT (GetDate()), SONum FROM TestTrigger
Please assist where I am going wrong.
If you want to look at just the rows that were inserted, you must use the Inserted pseudo table - not the dbo.TestTrigger base table....
ALTER TRIGGER dbo.InsertTriggerTest
ON irfaan.dbo.TestTrigger
FOR INSERT
AS
INSERT INTO TriggerInsert (CurrTime, IOFNum)
SELECT GETDATE(), SONum
FROM Inserted
Your SELECT query is returning all rows from your source table (TestTrigger). Use the table inserted instead. It will contain just the rows that are being inserted into TestTrigger instead of all of the rows as you are currently getting.
INSERT into TriggerInsert (CurrTime, IOFNum) SELECT (GetDate()), SONum FROM Inserted
I am using Microsoft SQL Server Management Studio.
I want to sum each row of my record (say, column ID) with a constant value (say 50).
So here is a better picture:
Click here for the image that i prepared for better understanding of my requirement.
I know SUM can be used to sum up the entire column and come out with a TOTAL at the end of the row, but how about adding every row's record with a constant value?
Once the sum is done, I need to do my last step, which is to reset the ID of the next new row (which doesn't need to SUM like above) from 154 to 999. Can anyone also advice me on resetting primary key?
Dick,
You can change the identity column's next value easily by executing DBCC CheckIdent command
Unfortunately, there is not an easy way to update an identity column value.
For existing records, what I experienced till now is to copy all data into a new temp table and organize values on this helper table. Then drop existing table. As following step rename the temp table to original table name.
If you try to remove identity property of a column, the SSMS generates a script as follows
BEGIN TRANSACTION
SET QUOTED_IDENTIFIER ON
SET ARITHABORT ON
SET NUMERIC_ROUNDABORT OFF
SET CONCAT_NULL_YIELDS_NULL ON
SET ANSI_NULLS ON
SET ANSI_PADDING ON
SET ANSI_WARNINGS ON
COMMIT
BEGIN TRANSACTION
GO
CREATE TABLE dbo.Tmp_MyTable
(
id int NOT NULL,
value int NULL
) ON [PRIMARY]
GO
ALTER TABLE dbo.Tmp_MyTable SET (LOCK_ESCALATION = TABLE)
GO
IF EXISTS(SELECT * FROM dbo.MyTable)
EXEC('INSERT INTO dbo.Tmp_MyTable (id, value)
SELECT id, value FROM dbo.MyTable WITH (HOLDLOCK TABLOCKX)')
GO
DROP TABLE dbo.MyTable
GO
EXECUTE sp_rename N'dbo.Tmp_MyTable', N'MyTable', 'OBJECT'
GO
COMMIT
I know this does not sound an easy way to update identity column values.
Is it possible to add a column to a table at a specific ordinal position in Microsoft SQL Server?
For instance, our tables always have CreatedOn, CreatedBy, LastModifiedOn, LastModifiedBy columns at the "end" of each table definition? I'd like the new column to show up in SSMS above these columns.
If I am scripting all my database changes, is there a way to preserve this order at the end of the table?
FYI, I'm not trying to institute a flame war on if this should even be done. If you want to read about a thread that degenerates quickly into that, here's a good one:
http://www.developersdex.com/sql/message.asp?p=581&r=5014513
You have to create a temp table that mirrors the original table's schema but with the column order that you want, then copy the contents of the original to temp. Delete the original and rename the temp.
This is what SQL Management Studio does behind the scenes.
With a schema sync tool, you can generate these scripts automatically.
go into SQL Server management Studio, and "design" an existing table. Insert a column in the middle, right click in an empty area and select Generate Change Script...
Now look at the script it creates. it will basically create a temp table with the proper column order, insert the data from the original table, drop the original table, and rename the temp table. This is probably what you'll need to do.
You may also need to uncheck this option to allow creation of change scripts
The answer is yes, it is technically possible, but you will have a headache doing so and it will take a long time to execute and set up.
One: Create/Copy/Drop/Rename
This is actually what SQL Server is doing in the graphical interface: here's an example of the script it is generating and executing when you click the 'save' button after adding a new column to the beginning of a table.
/* To prevent any potential data loss issues, you should review this script in detail before running it outside the context of the database designer.*/
BEGIN TRANSACTION
SET QUOTED_IDENTIFIER ON
SET ARITHABORT ON
SET NUMERIC_ROUNDABORT OFF
SET CONCAT_NULL_YIELDS_NULL ON
SET ANSI_NULLS ON
SET ANSI_PADDING ON
SET ANSI_WARNINGS ON
COMMIT
BEGIN TRANSACTION
GO
CREATE TABLE dbo.Tmp_SomeTable
(
MyNewColumn int NOT NULL,
OriginalIntColumn int NULL,
OriginalVarcharColumn varchar(100) NULL
) ON [PRIMARY]
TEXTIMAGE_ON [PRIMARY]
GO
ALTER TABLE dbo.Tmp_SomeTable SET (LOCK_ESCALATION = TABLE)
GO
SET IDENTITY_INSERT dbo.Tmp_SomeTable ON
GO
IF EXISTS(SELECT * FROM dbo.SomeTable)
EXEC('INSERT INTO dbo.Tmp_SomeTable (OriginalIntColumn, OriginalVarcharColumn FROM dbo.SomeTable WITH (HOLDLOCK TABLOCKX)')
GO
SET IDENTITY_INSERT dbo.Tmp_SomeTable OFF
GO
DROP TABLE dbo.SomeTable
GO
EXECUTE sp_rename N'dbo.Tmp_SomeTable', N'SomeTable', 'OBJECT'
GO
GO
COMMIT
Two: ADD COLUMN / UPDATE / DROP COLUMN / RENAME
This method basically involves creating a copy of any existing columns that you want to add to the 'right' of your new column, transferring the data to the new column, then dropping the originals and renaming the new ones. This will play havoc with any indexes or constraints you have, since you have to repoint them. It's technically possible, but again time-consuming both in terms of development and execution.
CREATE TABLE MyTest (a int, b int, d int, e int)
INSERT INTO MyTest (a,b,d,e) VALUES(1,2,4,5)
SELECT * FROM MyTest -- your current table
ALTER TABLE MyTest ADD c int -- add a new column
ALTER TABLE MyTest ADD d_new int -- create copies of the existing columns you want to move
ALTER TABLE MyTest ADD e_new int
UPDATE MyTest SET d_new = d, e_new = e -- transfer data to the new columns
ALTER TABLE MyTest DROP COLUMN d -- remove the originals
ALTER TABLE MyTest DROP COLUMN e
EXEC SP_RENAME 'MyTest.d_new', 'd'; -- rename the new columns
EXEC SP_RENAME 'MyTest.e_new', 'e';
SELECT * FROM MyTest
DROP TABLE MyTest -- clean up the sample
Three: Live with it
This mightily offends my sense of order ... but sometimes, it just isn't worth reshuffling.
To my knowledge there is no known method to change the order of the column. Behind the scenes SQL Management Studio does what Jose Basilio said. And if you have a big table then it is impractical to change the column orders like this way.
You can use a "view". With SQL views you can use any order you like without getting affected by the table column changes.
I am using SSMS 18. I did in simple way
Opened design of table
positioning the required column by dragging it
And as per the answer from KM (second in thread) - uncheck the option to allow creation of change scripts refer image above.
Save the changes.
Done. Check your table now.
TFS 2013 will do this for you automatically.
Add the new column(s) to your table anyway you like, and then commit your changes to TFS. From there you can open the table's sql file in Visual Studio and manually move the order of the columns in the T-SQL CREATE script. Then you can update your target database by using VS's schema compare tool found under Tools > SQL Server > New Schema Comparison. Choose your Database project with your change as the source, and the database you want to update as the target. Compare, select the table's script, and Update. VS will drop and add automatically. All your data will be safe, and indexes too.
What i think is simple is to add the column ALTER TABLE table1 ADD .. and then create a tmp table like tmp_table1 from the select like
SELECT col1,col2,col5,col3,col4 into tmp_table1 from table1;
and then drop table1 and rename the tmp_table1 to table1, that is it. I hope it will help someone
Select all the columns into a temp table, and create a new table with the new column you want. Then drop the old table, select all the columns from the temp table, and insert them into the new table with the reordered column. No data is lost.
SELECT * FROM TEMP
SELECT * FROM originaltbl
SELECT * FROM #Stagintbl
DECLARE #ColumnName nvarchar(max);
SET #ColumnName=(SELECT
DISTINCT STUFF((
SELECT ',' + a.COLUMN_NAME
FROM (
SELECT Column_name
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_NAME='originaltbl') a
for xml path('')
),1,1,'') AS ColumnName)
DECLARE #Sqlquery nvarchar(max)
SET #Sqlquery = 'SELECT ' + #ColumnName + ' FROM #Stagintbl' + '';
INSERT INTO originaltbl
EXECUTE(#Sqlquery)
Dirty and simple.
Export table to csv.
Insert new data at desired position.
Drop table.
Create new table with desired column specifications.
Load columns from csv to new table.
I am not sure if the thread is still active. I was having the same query with MySQL database. Right clicking the table and selecting 'ALTER' auto generated the below code. Sample provided from sakila db and it worked. Just find out the column after which you want to place your new column and use 'AFTER' keyword
ALTER TABLE `sakila`.`actor`
CHANGE COLUMN `middle_name` `middle_name` VARCHAR(50) NULL DEFAULT NULL AFTER `first_name`;