UPDATE
Here are the constraints as a result of the query
SELECT * FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE WHERE TABLE_NAME = 'history'
CONSTRAINT_NAME COLUMN_NAME ORDINAL_POSITION
PK_history userKey 1
PK_history name 2
Here is the result of the query
SELECT *
FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS
WHERE TABLE_NAME = 'history'
CONSTRAINT_NAME CONSTRAINT_TYPE IS_DEFERRABLE INITIALLY_DEFERRED
PK_history PRIMARY KEY NO NO
END UPDATE
My host provides an interface to my SQL Server DB via ASP.NET Enterprise Manager.
I have 3 columns in my history
table:
userId
(key, int, NULL not allowed)name
(key, string, NULL not allowed)id
(not key, int, NULL allowed)I want to make the id column the only key.
To do that, I believe I need to:
However, when I use the UI provided, it never works. Sometimes it'll just look like it tries to do something but it never changes when I refresh the view of the columns. It occasionally creates a temp table that looks like it tried to do some of the operation, but that never gets copied/overwrites the original table that I'm trying to change.
When I try using a query, the changes don't show up either. Here are the queries I think I need:
SELECT * from history WHERE id is NULL <---- This shows 0 results
ALTER TABLE history
ALTER COLUMN id int NOT NULL
ALTER TABLE history ADD PRIMARY KEY (id)
ALTER TABLE history
DROP CONSTRAINT userId
DROP CONSTRAINT name
GO
I've only gotten to the attempt to disallow NULLs and to add the primary key for the id column. It doesn't seem to work. Can someone point me in the right direction? Thanks!
To change the primary key of a table, delete the existing key using a DROP clause in an ALTER TABLE statement and add the new primary key.
Short answer: yes you can.
In SQL Server, you can use the sp_rename stored procedure to rename a user created object in the current database, including a primary key. This can be handy if you've got a primary key that had its name automatically assigned, and you now want to give it a more readable name.
Assuming that your current primary key constraint is called pk_history, you can replace the following lines:
ALTER TABLE history ADD PRIMARY KEY (id)
ALTER TABLE history
DROP CONSTRAINT userId
DROP CONSTRAINT name
with these:
ALTER TABLE history DROP CONSTRAINT pk_history
ALTER TABLE history ADD CONSTRAINT pk_history PRIMARY KEY (id)
If you don't know what the name of the PK is, you can find it with the following query:
SELECT *
FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS
WHERE TABLE_NAME = 'history'
Necromancing.
It looks you have just as good a schema to work with as me...
Here is how to do it correctly:
In this example, the table name is dbo.T_SYS_Language_Forms, and the column name is LANG_UID
-- First, chech if the table exists...
IF 0 < (
SELECT COUNT(*) FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_TYPE = 'BASE TABLE'
AND TABLE_SCHEMA = 'dbo'
AND TABLE_NAME = 'T_SYS_Language_Forms'
)
BEGIN
-- Check for NULL values in the primary-key column
IF 0 = (SELECT COUNT(*) FROM T_SYS_Language_Forms WHERE LANG_UID IS NULL)
BEGIN
ALTER TABLE T_SYS_Language_Forms ALTER COLUMN LANG_UID uniqueidentifier NOT NULL
-- No, don't drop, FK references might already exist...
-- Drop PK if exists
-- ALTER TABLE T_SYS_Language_Forms DROP CONSTRAINT pk_constraint_name
--DECLARE @pkDropCommand nvarchar(1000)
--SET @pkDropCommand = N'ALTER TABLE T_SYS_Language_Forms DROP CONSTRAINT ' + QUOTENAME((SELECT CONSTRAINT_NAME FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS
--WHERE CONSTRAINT_TYPE = 'PRIMARY KEY'
--AND TABLE_SCHEMA = 'dbo'
--AND TABLE_NAME = 'T_SYS_Language_Forms'
----AND CONSTRAINT_NAME = 'PK_T_SYS_Language_Forms'
--))
---- PRINT @pkDropCommand
--EXECUTE(@pkDropCommand)
-- Instead do
-- EXEC sp_rename 'dbo.T_SYS_Language_Forms.PK_T_SYS_Language_Forms1234565', 'PK_T_SYS_Language_Forms';
-- Check if they keys are unique (it is very possible they might not be)
IF 1 >= (SELECT TOP 1 COUNT(*) AS cnt FROM T_SYS_Language_Forms GROUP BY LANG_UID ORDER BY cnt DESC)
BEGIN
-- If no Primary key for this table
IF 0 =
(
SELECT COUNT(*) FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS
WHERE CONSTRAINT_TYPE = 'PRIMARY KEY'
AND TABLE_SCHEMA = 'dbo'
AND TABLE_NAME = 'T_SYS_Language_Forms'
-- AND CONSTRAINT_NAME = 'PK_T_SYS_Language_Forms'
)
ALTER TABLE T_SYS_Language_Forms ADD CONSTRAINT PK_T_SYS_Language_Forms PRIMARY KEY CLUSTERED (LANG_UID ASC)
;
-- Adding foreign key
IF 0 = (SELECT COUNT(*) FROM INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS WHERE CONSTRAINT_NAME = 'FK_T_ZO_SYS_Language_Forms_T_SYS_Language_Forms')
ALTER TABLE T_ZO_SYS_Language_Forms WITH NOCHECK ADD CONSTRAINT FK_T_ZO_SYS_Language_Forms_T_SYS_Language_Forms FOREIGN KEY(ZOLANG_LANG_UID) REFERENCES T_SYS_Language_Forms(LANG_UID);
END -- End uniqueness check
ELSE
PRINT 'FSCK, this column has duplicate keys, and can thus not be changed to primary key...'
END -- End NULL check
ELSE
PRINT 'FSCK, need to figure out how to update NULL value(s)...'
END
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