I'm trying to add the NOT_NULL constraint to a column in an SQL h2 database, using
ALTER TABLE CHARACTERS ADD CONSTRAINT nn_PID NOT_NULL (PLAYER_ID);
This follows the pattern I found here:
ALTER TABLE Persons ADD CONSTRAINT pk_PersonID PRIMARY KEY (P_Id,LastName)
Except I change the constraint, table and column names. But I get this error:
Syntax error in SQL statement "ALTER TABLE CHARACTERS ADD CONSTRAINT NN_PID NOT_NULL[*] (PLAYER_ID) "; expected "., COMMENT, PRIMARY, INDEX, KEY, CHECK, UNIQUE, FOREIGN"; SQL statement:
ALTER TABLE CHARACTERS ADD CONSTRAINT nn_PID NOT_NULL (PLAYER_ID) [42001-168] 42001/42001 (Help)
How can I add the NOT_NULL constraint?
From H2 SQL Grammar:
ALTER TABLE TEST ALTER COLUMN NAME SET NOT NULL;
So we can use:
ALTER TABLE CHARACTERS ALTER PLAYER_ID SET NOT NULL;
Related
Help! Can't figur it out what's the problem here --> ORA-00920: invalid relational operator.
alter table kund
add constraint kund_persnr_pk primary key(persnr)
add constraint kund_username_uq unique (username)
add constraint kund_kredittyp_ck check(kredittyp 'hög', 'medel', 'låg');
Do you want to check that the kredittyp column can have one of three values?
ALTER TABLE kund
ADD CONSTRAINT kund_persnr_pk PRIMARY KEY (persnr),
CONSTRAINT kund_username_uq UNIQUE (username),
CONSTRAINT kund_kredittyp_ck CHECK (kredittyp IN ('hög', 'medel', 'låg'));
What should be the sql command(oracle) to add 'NOT NULL' constraint, with a constraint name, to a column of existing table?
alter table t add constraint my_named_not_null check ( x is not null );
I know how to change the length of a column, but my SQL statement fails because the column I'm trying to change is a PK, so I get the following error:
Msg 5074, Level 16, State 1, Line 1
The object 'PK_TableName' is dependent on column 'PersonID'.
PersonID = PK.
I've read What is the sql to change the field length of a table column in sql server which only applies to non-PK columns.
I tried this:
ALTER TABLE table_name
ALTER COLUMN column_name <new datatype>
See below sample example how to increase size of the primary column
Create a sample table
create table abc (id varchar(10) primary key)
Find primary constraint in key constraints tables
select object_name(object_id),* from sys.key_constraints where object_name(parent_object_id) = 'abc
Drop constraint
ALTER TABLE abc
DROP CONSTRAINT PK__abc__3213E83F74EAC69B
(Replace PK__abc__3213E83F74EAC69B with constraint name you receive.)
Add not null
ALTER TABLE abc alter column id varchar(20) NOT NULL;
Add primary key again
ALTER TABLE abc
ADD CONSTRAINT MyPrimaryKey PRIMARY KEY (id)
ALTER TABLE <Table_Name>
DROP CONSTRAINT <constraint_name>
ALTER TABLE table_name
ALTER COLUMN column_name datatype
ALTER TABLE <Table_Name>
ADD CONSTRAINT <constraint_name> PRIMARY KEY (<Column1>,<Column2>)
SQLServer 2008 did not allow me to change a primary key with data so I deactivated all the constraints, performed the command and activated all the constraints again. The commands are:
EXEC sp_MSforeachtable #command1="ALTER TABLE ? NOCHECK CONSTRAINT ALL"
-- commands here
EXEC sp_MSforeachtable #command1="ALTER TABLE ? CHECK CONSTRAINT ALL"
I have a table in Oracle which has following schema:
City_ID Name State Country BuildTime Time
When I declared the table my primary key was both City_ID and the BuildTime, but now I want to change the primary key to three columns:
City_ID BuildTime Time
How can I change the primary key?
Assuming that your table name is city and your existing Primary Key is pk_city, you should be able to do the following:
ALTER TABLE city
DROP CONSTRAINT pk_city;
ALTER TABLE city
ADD CONSTRAINT pk_city PRIMARY KEY (city_id, buildtime, time);
Make sure that there are no records where time is NULL, otherwise you won't be able to re-create the constraint.
You will need to drop and re-create the primary key like this:
alter table my_table drop constraint my_pk;
alter table my_table add constraint my_pk primary key (city_id, buildtime, time);
However, if there are other tables with foreign keys that reference this primary key, then you will need to drop those first, do the above, and then re-create the foreign keys with the new column list.
An alternative syntax to drop the existing primary key (e.g. if you don't know the constraint name):
alter table my_table drop primary key;
Sometimes when we do these steps:
alter table my_table drop constraint my_pk;
alter table my_table add constraint my_pk primary key (city_id, buildtime, time);
The last statement fails with
ORA-00955 "name is already used by an existing object"
Oracle usually creates an unique index with the same name my_pk. In such a case you can drop the unique index or rename it based on whether the constraint is still relevant.
You can combine the dropping of primary key constraint and unique index into a single sql statement:
alter table my_table drop constraint my_pk drop index;
check this:
ORA-00955 "name is already used by an existing object"
In mysql, can I add a column and foreign key in the same statement? And what is the proper syntax for adding the fk?
Here is my SQL:
ALTER TABLE database.table
ADD COLUMN columnname INT DEFAULT(1),
FOREIGN KEY (fk_name) REFERENCES reftable(refcolumn) ON DELETE CASCADE;
...and the accompanying error message:
You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'FOREIGN KEY (fk_name) REFERENCES reftable(refcolumn) ON DELETE CASCADE' at line 4
Try this:
ALTER TABLE database.table
ADD COLUMN columnname INT DEFAULT(1),
ADD FOREIGN KEY fk_name(fk_column) REFERENCES reftable(refcolumn) ON DELETE CASCADE;
The following query adds a column by alter query and the constraint query makes it a FK in a single mysql query. You can do it like this,
SYNTAX:
ALTER TABLE `SCHEMANAME`.`TABLE1`
ADD COLUMN `FK_COLUMN` BIGINT(20) NOT NULL,
ADD CONSTRAINT `FK_TABLE2_COLUMN` FOREIGN KEY (`FK_COLUMN`)
REFERENCES `SCHEMANAME`.`TABLE2`(`PK_COLUMN`);
EXAMPLE:
ALTER TABLE `USERDB`.`ADDRESS_TABLE`
ADD COLUMN `USER_ID` BIGINT(20) NOT NULL AFTER `PHONE_NUMBER`,
ADD CONSTRAINT `FK_CUSTOMER_TABLE_CUSTOMER_ID` FOREIGN KEY (`USER_ID`)
REFERENCES `USERDB`.`CUSTOMER_TABLE`(`CUSTOMER_ID`);
This can be simplified a bit. You just need to add the "ADD" keyword before "FOREIGN KEY". Adding example below.
ALTER TABLE database.table
ADD COLUMN columnname INT DEFAULT(1),
ADD FOREIGN KEY (fk_name) REFERENCES reftable(refcolumn) ON DELETE CASCADE;
You can use it.
ALTER TABLE database.table
ADD COLUMN columnname INT DEFAULT(1);
ALTER TABLE database.table add FOREIGN KEY (fk_name) REFERENCES reftable(refcolumn) ON DELETE CASCADE;