In my mssql database I need to create a trigger that will disallow inserting negative budget to projects table. I don't really know how can I do it. All kind of help will be appreciated!
CREATE TRIGGER budget on PROJ FOR INSERT
For all answers ommiting triggers - unfortunately I need to do this with trigger
You do not need a trigger for this. SQL Server supports check constraints:
alter table projects add constraint chk_projects_budget check (budget >= 0);
There is no reason for not using a CHECK constraint. However you can certainly implement that constraint with a trigger by checking if there is any new row that has negative budget and raising an error on that case.
CREATE TRIGGER projects_positive_budget ON projects
FOR INSERT, UPDATE
IF EXISTS (SELECT * FROM inserted WHERE budget < 0)
BEGIN
RAISERROR('No negative budget is allowed', 16, -1);
ROLLBACK;
RETURN
END
GO
If you want to check multiple columns you can also
ALTER TABLE YourTableName
ADD CONSTRAINT CH_CheckForNegative CHECK(Col1 >=0 AND Col2 >= 0);
You can try this to add constraint for checking acceptable integer values either positive or negative.
CREATE TABLE [dbo].[Tbl](
[F1] [int] NULL,
[F2] [int] NULL
) ON [PRIMARY]
GO
--To accept only positive numbers and 0
ALTER TABLE [dbo].[Tbl] WITH CHECK ADD CONSTRAINT [CK_Tbl] CHECK (([F1]>=(0)))
GO
--To check constraint on the table
ALTER TABLE [dbo].[Tbl] CHECK CONSTRAINT [CK_Tbl]
GO
--To accept only negative numbers and 0
ALTER TABLE [dbo].[Tbl] WITH CHECK ADD CONSTRAINT [CK_Tbl_1] CHECK (([F2]<=(0)))
For more information you can check the link Integer Constraint
Related
I am getting this error
ORA-02438: Column check constraint cannot reference other columns
when I am performing this query
alter table Issue
modify Issue_Date not null check (Issue_Date <= sys_date);
as well as I have to add this condition also (issue_date<return_date);
and when I tried this
alter table Issue
add constraint ck_Issue_Date not null check (Issue_Date <= sys_date);
ERROR ORA-00904: : invalid identifier
I suspect you are wanting to reference the Oracle SYSDATE function, not a column named sys_date.
Unfortunately, the conditions in a CHECK CONSTRAINT cannot reference the SYSDATE function.
To get the database enforce this type of restriction on the value of a column, that would require a TRIGGER.
For example, something like this:
CREATE OR REPLACE TRIGGER trg_issue_issue_date_biu
BEFORE INSERT OR UPDATE ON Issue
FOR EACH ROW
BEGIN
IF (NEW.Issue_Date <= SYSDATE) THEN
NULL;
ELSE
RAISE_APPLICATION_ERROR(-20000, 'Invalid: Issue_Date is NULL or >SYSDATE');
END IF;
END;
You tried to mix up inline column level constraint and table level constraint (for more than 1 column). Please simply split them on 2 statements:
alter table Issue
modify Issue_Date not null;
alter table Issue
add constraint ck_Issue_Date check (Issue_Date <= sys_date);
alter table Issue
add constraint ck_Issue_Date2 check (issue_date<return_date);
I'm trying to create a constraint that does not allow dates in future years. I have this:
ALTER TABLE PACIENTE ADD CONSTRAINT ck_FechaNacimiento
CHECK (FechaNacimiento<=current_date);
But i'm getting error 02436.
You cannot create a non-deterministic constraint. So you cannot create a constraint that references a function like current_date or sysdate that returns a different value every time you call it.
If you want to enforce this sort of thing, you'd need to create a trigger on the table that throws an error if the business rule is violated, i.e.
CREATE OR REPLACE TRIGGER trg_paciente
BEFORE INSERT OR UPDATE
ON paciente
FOR EACH ROW
BEGIN
IF( :new.FechaNacimiento > current_date )
THEN
RAISE_APPLICATION_ERROR( -20001, 'FechaNacimiento<=current_date must be in the past' );
END IF;
END;
I'd tried again with this and didn't show error, thanks by the way:
ALTER TABLE EXAMENPACIENTE ADD CONSTRAINT ExamenPaciente_FechaExamen_c1
CHECK (FechaExamen<='30-SEP-2013');
ALTER TABLE PACIENTE ADD CONSTRAINT ck_FechaNacimiento CHECK (FechaNacimiento<=SYSDATE);
I want to make sure that a person's Date of Birth must be less than the current date.
So I declared in a table:
staff_dob SMALLDATETIME NOT NULL CHECK (GETDATE() < staff_dob)
But when I keep getting conflicts with the check constraint. How do I fix this? Do I need to formate GETDATE() into a proper format that I use? I'm unsure on how to do it.
Try this code:
drop table test
create table test
(staff_dob datetime check (staff_dob < getdate()))
--this insert will fail
insert test
(staff_dob)
values
('1/1/2013')
--this insert will succeed
insert test
(staff_dob)
values
('1/1/2011')
I think your check comparison was in the wrong direction.
take a look at Creating and Modifying CHECK Constraints
CREATE TABLE [dbo].[Staff](
[staffid] [int] NULL,
[dob] [date] NULL
) ON [PRIMARY]
GO
ALTER TABLE [dbo].[Staff] WITH CHECK ADD CONSTRAINT [CK_Staff] CHECK (([dob]<getdate()))
GO
ALTER TABLE [dbo].[Staff] CHECK CONSTRAINT [CK_Staff]
GO
hope this helps
I use SQL Server 2008
I use a CHECK CONSTRAINT on multiple columns in the same table to try to validate data input.
I receive an error:
Column CHECK constraint for column
'AAAA' references another column,
table 'XXXX'.
CHECK CONSTRAINT does not work in this way.
Any other way to implement this on a single table without using FK?
Thanks
Here an example of my code
CREATE TABLE dbo.Test
(
EffectiveStartDate dateTime2(2) NOT NULL,
EffectiveEndDate dateTime2(2) NOT NULL
CONSTRAINT CK_CmsSponsoredContents_EffectiveEndDate CHECK (EffectiveEndDate > EffectiveStartDate),
);
Yes, define the CHECK CONSTRAINT at the table level
CREATE TABLE foo (
bar int NOT NULL,
fred varchar(50) NOT NULL,
CONSTRAINT CK_foo_stuff CHECK (bar = 1 AND fred ='fish')
)
You are declaring it inline as a column constraint
...
fred varchar(50) NOT NULL CONSTRAINT CK_foo_fred CHECK (...)
...
Edit, easier to post than describe. Fixed your commas.
CREATE TABLE dbo.Test
(
EffectiveStartDate dateTime2(2) NOT NULL,
EffectiveEndDate dateTime2(2) NOT NULL, --need comma
CONSTRAINT CK_CmsSponsoredContents_EffectiveEndDate CHECK (EffectiveEndDate > EffectiveStartDate) --no comma
);
Of course, the question remains are you using a CHECK constraint where it should be an FK constraint...?
Check constraints can refer to a single column or to the whole record.
Use this syntax for record-level constraints:
ALTER TABLE MyTable
ADD CONSTRAINT MyCheck
CHECK (...your check expression...)
You can simply apply your validation in a trigger on the table especially that either way the operation will be rolled back if the check failed.
I found it more useful for CONSTRAINT using case statements.
ALTER TABLE dbo.ProductStock
ADD
CONSTRAINT CHK_Cost_Sales
CHECK ( CASE WHEN (IS_NOT_FOR_SALE=0 and SAL_CPU <= SAL_PRICE) THEN 1
WHEN (IS_NOT_FOR_SALE=1 ) THEN 1 ELSE 0 END =1 )
This is probably a simple answer but I can't find it. I have a table with a column of integers and I want to ensure that when a row is inserted that the value in this column is greater than zero. I could do this on the code side but thought it would be best to enforce it on the table.
Thanks!
I was in error with my last comment all is good now.
You can use a check constraint on the column. IIRC the syntax for this looks like:
create table foo (
[...]
,Foobar int not null check (Foobar > 0)
[...]
)
As the poster below says (thanks Constantin), you should create the check constraint outside the table definition and give it a meaningful name so it is obvious which column it applies to.
alter table foo
add constraint Foobar_NonNegative
check (Foobar > 0)
You can get out the text of check constraints from the system data dictionary in sys.check_constraints:
select name
,description
from sys.check_constraints
where name = 'Foobar_NonNegative'
Create a database constraint:
ALTER TABLE Table1 ADD CONSTRAINT Constraint1 CHECK (YourCol > 0)
You can have pretty sophisticated constraints, too, involving multiple columns. For example:
ALTER TABLE Table1 ADD CONSTRAINT Constraint2 CHECK (StartDate<EndDate OR EndDate IS NULL)
I believe you want to add a CONSTRAINT to the table field:
ALTER TABLE tableName WITH NOCHECK
ADD CONSTRAINT constraintName CHECK (columnName > 0)
That optional NOCHECK is used to keep the constraint from being applied to existing rows of data (which could contain invalid data) & to allow the constraint to be added.
Add a CHECK constraint when creating your table
CREATE TABLE Test(
[ID] [int] NOT NULL,
[MyCol] [int] NOT NULL CHECK (MyCol > 1)
)
you can alter your table and add new constraint like bellow.
BEGIN TRANSACTION
GO
ALTER TABLE dbo.table1 ADD CONSTRAINT
CK_table1_field1 CHECK (field1>0)
GO
ALTER TABLE dbo.table1 SET (LOCK_ESCALATION = TABLE)
GO
COMMIT