i'm using oracle 11g r2 Express Edition and SQL Command line. i'm getting problem when i update the primary key the foreign key did not update. is there any solution?
this is the command for my 2 table
CREATE TABLE staff(staff_id number(5) not null primary key);
CREATE TABLE customer(customer_id number(5) not null primary key,staff_id number(5) not null references staff);
What exactly did you do?
What is your SQL statement?
Did you updated the primary key to a value that is consistent with some row in the customer table? Are you sure there was a corresponding row in the customer table?
Related
I'm creating a couple of Tables for an assignment.
So I created a Gardener Table and an Offering Table, with all the appropriate data types and NULL statuses, as well as the Primary Key constraint for each. In the Gardener table I've included offeringID, and vice versa.
When I try to add Foreign Key constraint offeringID to the Gardener Table I get an error.
After checking online, I realized I had forgotten to make offeringID and gardenerID in each other's tables UNIQUE, hence I altered table to add uniqueness.
Tried adding Foreign Key constraint and I get the same error. I reckon I may be understanding something wrongly, but I can't seem to put my finger on it.
Create Table Gardener
(gardenerID NUMBER(10) NOT NULL,
offeringID NUMBER(10) NOT NULL,
CONSTRAINT gardener_pk PRIMARY KEY(gardenerID)
);
Create Table Offering
(offeringID NUMBER(10) NOT NULL,
gardenerID NUMBER(10) NOT NULL,
CONSTRAINT offering_pk PRIMARY KEY(offeringID)
);
Alter Table Gardener
add CONSTRAINT offering_fk FOREIGN KEY(offeringID)
REFERENCES Offering(offeringID);
Alter Table Gardener
add Unique(offeringID);
Alter Table Offering
add Unique(gardenerID);
This is the error:
ORA-02270: no matching unique or primary key for this column-list
02270. 00000 - "no matching unique or primary key for this column-list"
Cause: A REFERENCES clause in a CREATE/ALTER TABLE statement gives a column-list
for which there is no matching unique or primary key constraint in the referenced table.
Like, I still don't get it. Isn't offeringID a Primary Key hence pointing to it from Gardener shouldn't be an issue still?
Since you're trying to add a a foreign key constraint for offering.offeringID column within the Gardener table, whereas that column has no unique/primary key key when you try to add a foreign key. i.e. operation stops at the 3rd command.
So, just exchange the order of commands as :
Alter Table Gardener
add Unique(offeringID); -- should be prior to the below command
Alter Table Gardener
add CONSTRAINT offering_fk FOREIGN KEY(offeringID)
REFERENCES Offering(offeringID);
Demo
Is any way, how to create table with CHECK (or maybe TRIGGER?), that will check, if inserted value is already in another table?
Example
CREATE TABLE Employee(
Name VARCHAR(10),
Adress VARCHAR(20)
);
CREATE TABLE Section(
Section_name VARCHAR(10),
Managers_name VARCHAR(10)
);
And I want to check, that value inserted to Managers_name is already in Employee, if it isnt, then print error.
I found any ways, how it could be done, but everything I tried in Oracle, didnt work.
Add a PRIMARY KEY constraint to the employee table and a FOREIGN KEY constraint to the section table:
CREATE TABLE Employee(
Name VARCHAR(10) CONSTRAINT Employee_Name_PK PRIMARY KEY,
Adress VARCHAR(20)
);
CREATE TABLE Section(
Section_name VARCHAR(10),
Managers_name VARCHAR(10)
CONSTRAINT section_manager_fk REFERENCES Employee( Name )
);
Check constraint is, as explained by mt0, devoted to single table.
Trigger is to be avoided for consistency reasons: while you're selecting a record, another session might be in the process of deleting it.
The Foreign Key is the correct way to implement it: Trap FK constraint violation in your code (ORA-02291 i guess), search for "section_manager_fk" in the message and finally rewrite a user-friendly error message.
In MS SQL Server it is possible to create a foreign key with ON UPDATE CASCADE option, so whenever you update one of the columns in the primary key, the foreign keys in other tables will also be update by the DBMS.
So, how to do it in Oracle?
Oracle does not allow a Foreign Key constraint with “ON UPDATE CASCADE”.
Here are a couple of options you have.
Create the Foreign Key, and create an “On Update” trigger.
Make use of the package below (needs to be installed in the db).
http://tkyte.blogspot.com/2009/10/httpasktomoraclecomtkyteupdatecascade.html
Let me know if you have additional questions or need more information.
Would a database trigger do the job for you ?
Here is the Oracle doc on the subject of Data Integrity for 11g (just incase you were interested).
You can't use on update cascade, but you can create a trigger that will resolve the issue:
create table tab1(
pk int PRIMARY KEY,
aa int);
create table tab2(
pk int PRIMARY KEY,
tab1_pk int,
FOREIGN KEY(tab1_pk) REFERENCES tab1(pk));
------------------------------------------
create or replace trigger tab1_pkUpdate
after update of pk on tab1
for each row
begin
update tab2 s
set s.tab1_pk = :new.pk
where s.tab1_pk = :old.pk;
end;
/
I have a primary key PK1 for the table TABLE1. Need to add one more column to the existing primary key.
I was tying the following alter script
ALTER TABLE TABLE1
ADD CONSTRAINT "PRIMARYKEYS" PRIMARY KEY
("PK1",
"PK2");
Error report:
SQL Error: ORA-02260: table can have only one primary key
02260. 00000 - "table can have only one primary key"
*Cause: Self-evident.
*Action: Remove the extra primary key.
How can I add one more column to the primary key, without affecting the data(data has been verified , there are no duplication.)
If you have concern about new data that violates PK can be added during the time interval when the old PK dropped, but the new one is not created, you can create a unique index first :
CREATE UNIQUE INDEX IDXU_TABLE1_PK ON TABLE1(PK1,PK2);
ALTER TABLE TABLE1 DROP CONSTRAINT [old_pk_constraint_name] ;
ALTER TABLE TABLE1 ADD CONSTRAINT "PRIMARYKEYS" PRIMARY KEY
(PK1,PK2) USING INDEX IDXU_TABLE1_PK;
Another option is to keep index associated with the old PK constraint until new PK is created :
ALTER TABLE TABLE1 DROP CONSTRAINT [old_pk_constraint_name] KEEP INDEX;
ALTER TABLE TABLE1 ADD CONSTRAINT "PRIMARYKEYS" PRIMARY KEY
(PK1,PK2) ;
DROP INDEX [name of unique index associated with the old PK constraint];
You need to drop old primary key first.
In MS SQL Server it is possible to create a foreign key with ON UPDATE CASCADE option, so whenever you update one of the columns in the primary key, the foreign keys in other tables will also be update by the DBMS.
So, how to do it in Oracle?
Oracle does not allow a Foreign Key constraint with “ON UPDATE CASCADE”.
Here are a couple of options you have.
Create the Foreign Key, and create an “On Update” trigger.
Make use of the package below (needs to be installed in the db).
http://tkyte.blogspot.com/2009/10/httpasktomoraclecomtkyteupdatecascade.html
Let me know if you have additional questions or need more information.
Would a database trigger do the job for you ?
Here is the Oracle doc on the subject of Data Integrity for 11g (just incase you were interested).
You can't use on update cascade, but you can create a trigger that will resolve the issue:
create table tab1(
pk int PRIMARY KEY,
aa int);
create table tab2(
pk int PRIMARY KEY,
tab1_pk int,
FOREIGN KEY(tab1_pk) REFERENCES tab1(pk));
------------------------------------------
create or replace trigger tab1_pkUpdate
after update of pk on tab1
for each row
begin
update tab2 s
set s.tab1_pk = :new.pk
where s.tab1_pk = :old.pk;
end;
/