I'm using SQL Server 2016 and trying to implement cascade on delete. It does work, but not if I put the code in a single script. The code for dropping the constraints on --subproject person and --activity then adding the constraint again have to be in separate files.
So this is in one file
ALTER TABLE dbo.SubProjectPerson
DROP CONSTRAINT SubProjectPerson_SubProject
and this is in another file
ALTER TABLE dbo.SubProjectPerson
ADD CONSTRAINT SubProjectPerson_SubProject
FOREIGN KEY (SubProjectID)
REFERENCES dbo.SubProject(SubProjectID)
ON DELETE CASCADE;
That is the only way it works
Here is the script that I have
BEGIN TRY
BEGIN TRANSACTION
--subproject person
ALTER TABLE dbo.SubProjectPersonRole
DROP CONSTRAINT SubProjectPersonRole_SubProjectPerson
ALTER TABLE dbo.SubProjectPersonRole
ADD CONSTRAINT SubProjectPersonRole_SubProjectPerson
FOREIGN KEY (SubProjectPersonID)
REFERENCES dbo.SubProjectPerson(SubProjectPersonID)
ON DELETE CASCADE;
ALTER TABLE dbo.SubProjectPerson
DROP CONSTRAINT SubProjectPerson_SubProject
ALTER TABLE dbo.SubProjectPerson
ADD CONSTRAINT SubProjectPerson_SubProject
FOREIGN KEY (SubProjectID)
REFERENCES dbo.SubProject(SubProjectID)
ON DELETE CASCADE;
--activity
ALTER TABLE dbo.Activity
DROP CONSTRAINT Activity_SubProject
ALTER TABLE dbo.Activity
ADD CONSTRAINT Activity_SubProject
FOREIGN KEY (SubProjectID)
REFERENCES dbo.SubProject(SubProjectID)
ON DELETE CASCADE;
--subproject
ALTER TABLE dbo.SubProjectDocument
DROP CONSTRAINT SubProjectDocument_SubProject
ALTER TABLE dbo.SubProjectDocument
ADD CONSTRAINT SubProjectDocument_SubProject
FOREIGN KEY (SubProjectID)
REFERENCES dbo.SubProject(SubProjectID)
ON DELETE CASCADE;
ALTER TABLE dbo.SubProjectNote
DROP CONSTRAINT SubProjectNote_SubProject
ALTER TABLE dbo.SubProjectNote
ADD CONSTRAINT SubProjectNote_SubProject
FOREIGN KEY (SubProjectID)
REFERENCES dbo.SubProject(SubProjectID)
ON DELETE CASCADE;
--communication thread
ALTER TABLE dbo.CommunicationThread
DROP CONSTRAINT CommunicationThread_SubProjectID
ALTER TABLE dbo.CommunicationThread
ADD CONSTRAINT CommunicationThread_SubProjectID
FOREIGN KEY (SubProjectID)
REFERENCES dbo.SubProject(SubProjectID)
ON DELETE CASCADE;
COMMIT TRANSACTION
END TRY
BEGIN CATCH
ROLLBACK TRANSACTION
END CATCH
This long script is running fine with no errors but no changes are being picked up for those two tables unless I run them in separate files. What's wrong here?
Try this. Use GO for every statement.
ALTER TABLE dbo.SubProjectDocument
DROP CONSTRAINT SubProjectDocument_SubProject
GO
ALTER TABLE dbo.SubProjectDocument
ADD CONSTRAINT SubProjectDocument_SubProject
FOREIGN KEY (SubProjectID)
REFERENCES dbo.SubProject(SubProjectID)
ON DELETE CASCADE;
Related
I have the following table
CREATE TABLE steps (
hash_id text UNIQUE PRIMARY KEY,
depth integer
);
-- Indices -------------------------------------------------------
CREATE UNIQUE INDEX steps_hash_id_key ON steps(hash_id text_ops);
CREATE UNIQUE INDEX steps_pkey ON steps(hash_id text_ops);
But I'd like to remove the redundant UNIQUE index because PRIMARY KEY is already unique.
I've also many other tables linked to the hash_id of my steps table with foreign keys.
When I try to remove my UNIQUE index like this:
ALTER TABLE steps DROP CONSTRAINT steps_hash_id_key;
I get
ERROR: cannot drop constraint steps_hash_id_key on table steps because other objects depend on it
DETAIL: constraint steps_routes_step_hash_id_fkey on table steps_routes depends on index steps_hash_id_key
constraint steps_likes_dislikes_step_hash_id_fkey on table steps_likes_dislikes depends on index steps_hash_id_key
HINT: Use DROP ... CASCADE to drop the dependent objects too.
The matter is that I don't want to cascade delete anything, I'd just like to remove this duplicated unique index. Is it possible ?
Thanks to the discussion in comments (#Gordon Linoff) here's a way to fix this issue:
Drop foreign keys
Drop Primary Keys and Unique Keys
Recreate Primary Key only
Recreate Foreign Keys
ALTER TABLE steps_routes DROP CONSTRAINT steps_routes_step_hash_id_fkey;
ALTER TABLE steps_likes_dislikes DROP CONSTRAINT steps_likes_dislikes_step_hash_id_fkey;
ALTER TABLE steps DROP CONSTRAINT steps_pkey;
ALTER TABLE steps DROP CONSTRAINT steps_hash_id_key;
ALTER TABLE steps ADD PRIMARY KEY (hash_id);
ALTER TABLE steps_routes ADD FOREIGN KEY (step_hash_id) REFERENCES steps(hash_id) ON DELETE CASCADE ON UPDATE CASCADE;
ALTER TABLE steps_likes_dislikes ADD FOREIGN KEY (step_hash_id) REFERENCES steps(hash_id) ON DELETE CASCADE ON UPDATE CASCADE;
I just want to know if there is any way to write some function or stored procedure in sql server to change the delete rule programmatically?
Example: I have to change the delete rule from Cascade to none or vice versa but I don't want to do graphically.
Because I have to do quite often and want to revert it back to its initial stage.
You can't alter a foreign key constraint to change the cascade option, you will have to drop it and create it again with the option you want. Make sure to set it on a transaction as you don't want inconsistent data getting stuck in the middle of the change.
The alter commands of an example:
ALTER TABLE [SchemaName].[TableName] DROP CONSTRAINT [ConstraintName]
ALTER TABLE [SchemaName].[TableName] WITH CHECK ADD CONSTRAINT [ConstraintName]
FOREIGN KEY([ColumnName]) REFERENCES [SchemaName].[YetAnotherTableName]([ColumnName]) ON DELETE CASCADE;
Let's assume you have a foreign key already called fk_table1_table2 with cascade none.
You would have to drop the constraint and then recreate a constraint with cascade:
ALTER TABLE [dbo].[TableName] DROP CONSTRAINT [FK_Table1_Table2]
GO
ALTER TABLE [dbo].[TableName] WITH NOCHECK ADD CONSTRAINT [FK_Table1_Table2] FOREIGN KEY([Table2])
REFERENCES [dbo].[Table2] ([ID])
ON UPDATE CASCADE
ON DELETE CASCADE
NOT FOR REPLICATION
GO
ALTER TABLE [dbo].[TableName] CHECK CONSTRAINT [FK_Table1_Table2]
GO
This is generated from ssms. You can do this like here:
You can right click on any Key and generate the code for you ;)
MS SQL Server
I'm making a star schema. I've set the PK's and FK for my tables and am now trying to write a procedure that will drop the constraints, truncate the tables, add the constraints again, and then repopulate the tables. When I try to drop the constraints I receive the error:
"The constraint PK_TIMEDIM is being referenced by table SalesFactTable, foreign key constraint FK_SALESFACTTABLE. Could not drop constraint."
EDIT: One problem solved. Another found. I receive the same error except now there are mysterious, auto-generated FK's such as FK__SalesFact__CUST___19DFD96B.
Please show me what I'm doing wrong.
ALTER PROCEDURE [dbo].[A11]
AS
BEGIN
--Drop constraints
ALTER TABLE SalesFactTable
DROP CONSTRAINT FK_SALESFACTTABLE
ALTER TABLE SalesFactTable
DROP CONSTRAINT PK_SALESFACTTABLE
ALTER TABLE TimeDim
DROP CONSTRAINT PK_TIMEDIM
ALTER TABLE CustomerDim
DROP CONSTRAINT PK_CUSTOMERDIM
ALTER TABLE PartDim
DROP CONSTRAINT PK_PARTDIM
--Truncate tables
TRUNCATE TABLE TimeDim
TRUNCATE TABLE CustomerDim
TRUNCATE TABLE PartDim
TRUNCATE TABLE SalesFactTable
--Add constraints
ALTER TABLE TimeDim
ADD CONSTRAINT PK_TIMEDIM PRIMARY KEY (TIME_ID)
ALTER TABLE CustomerDim
ADD CONSTRAINT PK_CUSTOMERDIM PRIMARY KEY (CUST_ID)
ALTER TABLE PartDim
ADD CONSTRAINT PK_PARTDIM PRIMARY KEY (PART_ID)
ALTER TABLE SalesFactTable
ADD CONSTRAINT FK_SALESFACTTABLE FOREIGN KEY (TIME_ID) REFERENCES TimeDim (TIME_ID),
FOREIGN KEY (CUST_ID) REFERENCES CustomerDim (CUST_ID),
FOREIGN KEY (PART_ID) REFERENCES PartDim (PART_ID)
ALTER TABLE SalesFactTable
ADD CONSTRAINT PK_SALESFACTTABLE PRIMARY KEY (TIME_ID, CUST_ID, PART_ID)
**Foreign keys are referenced by the Primary key, so you are not allowed to remove the primary key before removing the Foreign Key constraint.
so, you need to remove the foreign key first to remove the Primary key constraint from a table.
**
ALTER PROCEDURE [dbo].[A11]
AS
BEGIN
--Drop FK constraints
ALTER TABLE SalesFactTable
DROP CONSTRAINT FK_SALESFACTTABLE
--Drop PK constraints
ALTER TABLE SalesFactTable
DROP CONSTRAINT PK_SALESFACTTABLE
ALTER TABLE TimeDim
DROP CONSTRAINT PK_TIMEDIM
ALTER TABLE CustomerDim
DROP CONSTRAINT PK_CUSTOMERDIM
ALTER TABLE PartDim
DROP CONSTRAINT PK_PARTDIM
--Truncate tables
TRUNCATE TABLE TimeDim
TRUNCATE TABLE CustomerDim
TRUNCATE TABLE PartDim
TRUNCATE TABLE SalesFactTable
--Add constraints
ALTER TABLE TimeDim
ADD CONSTRAINT PK_TIMEDIM PRIMARY KEY (TIME_ID)
ALTER TABLE CustomerDim
ADD CONSTRAINT PK_CUSTOMERDIM PRIMARY KEY (CUST_ID)
ALTER TABLE PartDim
ADD CONSTRAINT PK_PARTDIM PRIMARY KEY (PART_ID)
ALTER TABLE SalesFactTable
ADD CONSTRAINT FK_SALESFACTTABLE FOREIGN KEY (TIME_ID) REFERENCES TimeDim (TIME_ID),
FOREIGN KEY (CUST_ID) REFERENCES CustomerDim (CUST_ID),
FOREIGN KEY (PART_ID) REFERENCES PartDim (PART_ID)
ALTER TABLE SalesFactTable
ADD CONSTRAINT PK_SALESFACTTABLE PRIMARY KEY (TIME_ID, CUST_ID, PART_ID)
SQL How to Alter Constraint
Below is 1 of my constraint
CONSTRAINT ACTIVEPROG_FKEY1 FOREIGN KEY(ActiveProgCode) REFERENCES PROGRAM(ActiveProgCode),
I want to add in
ON DELETE CASCADE
to the constraint above.
How do i alter that existing constraint ACTIVEPROG_FKEY1 and add
ON DELETE CASCADE
to constraint ACTIVEPROG_FKEY1
Consider ACTIVEPROG_FKEY1 is at Table ACTIVEPROG
You can not alter constraints ever but you can drop them and then recreate.
Have look on this
ALTER TABLE your_table DROP CONSTRAINT ACTIVEPROG_FKEY1;
and then recreate it with ON DELETE CASCADE like this
ALTER TABLE your_table
add CONSTRAINT ACTIVEPROG_FKEY1 FOREIGN KEY(ActiveProgCode) REFERENCES PROGRAM(ActiveProgCode)
ON DELETE CASCADE;
hope this help
No. We cannot alter the constraint, only thing we can do is drop and recreate it
ALTER TABLE [TABLENAME] DROP CONSTRAINT [CONSTRAINTNAME]
Foreign Key Constraint
Alter Table Table1 Add Constraint [CONSTRAINTNAME] Foreign Key (Column) References Table2 (Column) On Update Cascade On Delete Cascade
Primary Key constraint
Alter Table Table add constraint [Primary Key] Primary key(Column1,Column2,.....)
I'm changing constraints in my database and I need to drop some of them. I know that for a single constraint, the command is following:
ALTER TABLE tblApplication DROP CONSTRAINT constraint1_name;
However, when I try
ALTER TABLE tblApplication DROP (
CONSTRAINT constraint1_name,
CONSTRAINT constraint2_name,
CONSTRAINT constraint3_name
);
it doesn't work and I need to do:
ALTER TABLE tblApplication DROP CONSTRAINT constraint1_name;
ALTER TABLE tblApplication DROP CONSTRAINT constraint2_name;
ALTER TABLE tblApplication DROP CONSTRAINT constraint3_name;
Is there a way to remove more than one constraint in a single command? I'd like to avoid repeating ALTER TABLE tblApplication, just like with the ADD command:
ALTER TABLE tblApplication ADD (
CONSTRAINT contraint1_name FOREIGN KEY ... ENABLE,
CONSTRAINT contraint2_name FOREIGN KEY ... ENABLE,
CONSTRAINT contraint3_name FOREIGN KEY ... ENABLE
);
Yes you can. You just need to repeat 'drop constraint' per constraint. e.g.
alter table t1
drop constraint fk1
drop constraint fk2
/
Edit: I tested this against Oracle 11, and it worked fine. Don't know about older versions.
There is an alternative form to drop constraints related to a column in a table, also dropping the column with CASCADE:
ALTER TABLE table1 DROP (columnName) CASCADE CONSTRAINTS;
It is tested on Oracle 11g
example: we can drop constraints in MySQL by creating constraints to the variables like this way.
create table sample(id int, name varchar(30), marks int, constraint uid unique(id), constraint un unique(name));
alter table sample drop constraint uid, drop constraint un;
Yes, we can drop multiple at once:
ALTER TABLE TABLE NAME
DROP CONSTRAINTS CONSTRAINT VALUE
DROP CONSTRAINTS CONSTRAINT VALUE;