How can I specify that a table has multiple columns that makeup the primary key? When I run this sql statement, I get "unknown data type "("
CREATE TABLE SH_LEAGUE_CONTACT_TEAM_ROLE(ROLE_NAME VARCHAR NOT NULL,
TEAM_ID INT NOT NULL,
CONTACT_ID INT NOT NULL,
FOREIGN_KEY(TEAM_ID) REFERENCES SH_LEAGUE_TEAM(ID),
FOREIGN_KEY(CONTACT_ID) REFERENCES SH_LEAGUE_CONTACT(ID),
PRIMARY KEY(ROLE_NAME, TEAM_ID, CONTACT_ID));
You have a typo in your statement, you have used FOREIGN_KEY (one word) instead of FOREIGN KEY (two words).
Related
CREATE TABLE Route(
RouteNo VARCHAR(10),
Origin VARCHAR(30),
Destination VARCHAR(30),
DepartureTime VARCHAR(15),
SerialNo VARCHAR(5),
ArrivalTime VARCHAR(15),
PRIMARY KEY(RouteNo) );
CREATE TABLE Employee(
EmployeeID VARCHAR(5) NOT NULL,
Name VARCHAR(30),
Phone NUMBER,
JobTitle VARCHAR(30),
PRIMARY KEY(EmployeeID) );
CREATE TABLE Flight(
SerialNo VARCHAR(5),
RouteNo VARCHAR(5),
FlightDate DATE,
ActualTD VARCHAR(10),
ActualTA VARCHAR(10),
PRIMARY KEY(SerialNo, RouteNo, FlightDate),
FOREIGN KEY(RouteNo) REFERENCES Route(RouteNo),
FOREIGN KEY(SerialNo) REFERENCES Airplane(SerialNo) ); -- does Airplane table exists ?
CREATE TABLE CrewAssigment(
EmployeeID VARCHAR(5),
RouteNo VARCHAR(5),
FlightDate DATE,
Role VARCHAR(45),
Hours INT,
PRIMARY KEY(EmployeeID, RouteNo, FlightDate),
FOREIGN KEY(EmployeeID) REFERENCES Employee(EmployeeID),
FOREIGN KEY(RouteNo) REFERENCES Route(RouteNo),
FOREIGN KEY(FlightDate) REFERENCES Flight(FlightDate) );
Select * from CrewAssignment
This is my code where I'm getting an error in the CrewAssignment table and above are the tables where the foreign key is referenced from.
Error report -
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.
*Action: Find the correct column names using the ALL_CONS_COLUMNS
catalog view
A few objections.
This is clearly an Oracle question, not MySQL. How do I know? ORA-02270 is an Oracle database error code; pay attention to tags you use.
You should use VARCHAR2 datatype instead of VARCHAR. Why? Oracle recommends so.
create table flight fails first as it references the airplane table, and it doesn't exist yet (at least, not in code you posted)
error you're complaining about is due to create table crewassignment. One of its foreign keys references the flight table:
FOREIGN KEY(flightdate) REFERENCES flight(flightdate)
but flight's primary key is composite, made up of 3 columns:
PRIMARY KEY(serialno,
routeno,
flightdate)
which means that you can't create that foreign key.
So, what to do? No idea, I don't know rules responsible for such a data model. Either modify primary key of the flight table, or modify foreign key constraint of the crewassingment table.
Perhaps you could add a new column to flight table (made up of a sequence (or identity column, if your database version supports it) and then let the crewassignment table reference that primary key. Columns you currently use as a primary key (serialno, routeno, flightdate) would then switch to unique key.
I am new to here, please help me to find an answer to the below query.
"How to add a primary key constraint on two columns to make a composite key column in a table?"
Instead of writing so many lines, kindly provide the answer as short as possible with code.
(I am creating a table in which I can have only one primary key on the values of two-columns as a composite key.)
JacknJill
You can create such constraint in scope of CREATE TABLE operator
CREATE TABLE foo (
id INTEGER,
name VARCHAR(25),
bar VARCHAR(255),
CONSTRAINT foo_pk PRIMARY KEY (id,name)
);
or ALTER TABLE operator
CREATE TABLE foo (
id INTEGER,
name VARCHAR(25),
bar VARCHAR(255)
);
ALTER TABLE foo ADD CONSTRAINT foo_pk PRIMARY KEY (id,name);
I use oracle and I try to have a recursive relation
CREATE TABLE "EVENT"
(
"EVENT_ID" NUMBER(18) NOT NULL, //primary key
"NAME" VARCHAR(20) NULL,
"RELATED_EVENT_ID" NUMBER(18) NULL //foreign key
);
Event 1 parent is Event 2....
When I try to create this table, I get this error.
ALTER TABLE "EVENT"
ADD CONSTRAINT "FK_RELATED_EVENT_ID"
FOREIGN KEY ("RELATED_EVENT_ID") REFERENCES "EVENT" ("RELATED_EVENT_ID")
Error report -
SQL 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.
*Action: Find the correct column names using the ALL_CONS_COLUMNS
catalog view
You have two problems:
There is no primary key constraint on this table.
The foreign key constraint you defined has RELATED_EVENT_ID referencing RELATED_EVENT_ID. I suspect that was just a typo.
Change your table definition to:
CREATE TABLE EVENT
(EVENT_ID NUMBER
NOT NULL
CONSTRAINT PK_EVENT
PRIMARY KEY
USING INDEX,
NAME VARCHAR2(20),
RELATED_EVENT_ID NUMBER);
Then add the foreign key constraint as
ALTER TABLE EVENT
ADD CONSTRAINT EVENT_FK1
FOREIGN KEY (RELATED_EVENT_ID) REFERENCES EVENT(EVENT_ID);
db<>fiddle here
EDIT
Note that the better way to handle this is to use a junction table, such as:
CREATE TABLE EVENT_EVENT
(EVENT_ID1 NUMBER
CONSTRAINT EVENT_EVENT_FK1
REFERENCES EVENT(EVENT_ID),
EVENT_ID2 NUMBER
CONSTRAINT EVENT_EVENT_FK2
REFERENCES EVENT(EVENT_ID),
CONSTRAINT PK_EVENT_EVENT
PRIMARY KEY (EVENT_ID1, EVENT_ID2)
USING INDEX);
Then you can drop the RELATED_EVENT_ID column from EVENT as you no longer need it.
According to oracle document :
Foreign key specifies that the values in the column must correspond to values in a
referenced primary key or unique key column or that they are NULL.
In your case, create primary key on column (EVENT_ID) and use it in reference clause as following:
ALTER TABLE "EVENT"
ADD CONSTRAINT "FK_RELATED_EVENT_ID"
FOREIGN KEY ("RELATED_EVENT_ID")
REFERENCES "EVENT" ("EVENT_ID") -- this
Now, use EVENT2's EVENT_ID as RELATED_EVENT_ID in EVENT1 record to make EVENT2 as parent of EVENT1.
Cheers!!
i want to drop a column from composite primary key(not to delete from table). if my table is like this.
create table "scott"."xyz"(
"column1" not null,
"column2" not null,
"column3" not null,
"column4" not null,
"column5" not null,
"column6",
CONSTRAINT PRIMARY KEY ("column1","column2","column3","column4")
);
i want to alter this primary key to first three column without dropping it. beacuse i don't know CONSTRAINT name.
You don't need the constraint name:
ALTER TABLE "scott"."xyz" DROP PRIMARY KEY;
ALTER TABLE "scott"."xyz" ADD PRIMARY KEY ("column1","column2","column3");
But it is probably a good idea to give your PK a name in the future:
ALTER TABLE "scott"."xyz"
ADD CONSTRAINT pk_xyz PRIMARY KEY ("column1","column2","column3");
And I would not recommend to use quoted identifiers. You will have problems with various tools in the long run.
Something like:
create table Employee(
ID int primary key,
Name nvarchar(200)
IDArea int foreign key references Area(ID)
);
go
create table Area(
ID int primary key,
Name nvarchar(200)
);
Does something like this exist in Oracle?
Yes, just leave out the "GO" keywords and put the statements in a file:
create table Area(
ID int primary key,
Name nvarchar2(200)
);
create table Employee(
ID int primary key,
Name nvarchar2(200),
IDArea int references Area(ID)
);
You must create the Area primary key before the foreign key that references it, so I have swapped these around. Also the foreign key syntax is slightly different in Oracle.
You should first create the master table, forget nvarchar datatype, and eventually the script would be :
create table Area(
ID number primary key,
Name varchar2(200)
);
create table Employee(
ID number primary key,
Name varchar2(200) ,
IDArea number, constraint fk_idarea foreign key (idarea) references Area(ID)
);