CREATE TABLE Flight (
FlightNo int NOT NULL PRIMARY KEY,
FlightDate Date,
PlaneSerialNo int,
EmployeeID int,
RouteNo int,
CONSTRAINT FK_PlaneSerialNo FOREIGN KEY(PlaneSerialNo)
REFERENCES Plane(PlaneSerialNo),
CONSTRAINT FK_EmployeeID FOREIGN KEY(EmployeeID)
REFERENCES Employee(EmployeeID),
CONSTRAINT FK_RouteNo FOREIGN KEY(RouteNo)
REFERENCES Route(RouteNo)
);
trying to create a sort of database system using oracle where it tracks flights but it just says the name is already used but havent seen any similarities in constraints other than identifying FKs
Oracle doesn't rely much on similarities - it has found object with exactly the same name in its dictionary and - as you can't have two objects with the same name - it raised the error.
Query user_constraints (and then user_objects, if previous search didn't find anything).
If you want to find out which table it is, you might try
select owner, table_name from dba_constraints where constraint_name = '<some value from your create table command>';
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'm working on a project in which I'm writing queries from this database that I am attempting to create in PLSQL. However, before I can do that I must create the db, and some of the table-create statemens I'm trying to run are returning errors. Specifically, the errors seem to indicate that some of the primary keys I'm referencing don't exist. When I check to see if that is true I see the likely issue. For example, I try to do
create table group_disforum ( df_id int,
ig_id int,
constraint gdf_FK foreign key(ig_id) references Course_Interest_group(interest_gid),
constraint gdf_PK primary key(df_id, ig_id),
comments varchar(150)
)
setting the foreign key to the primary key(interest_gid) in Course_Interest_group.
However, the Course_Interest_group is this:
create table Course_Interest_group( interest_gid int,
gname varchar(20),
courseid int,
facultyid int,
past_gpa float,
constraint IG_PK primary key(interest_gid, courseid, facultyid),
constraint IG_FK1 foreign key(courseid) references course(courseid),
constraint IG_FK2 foreign key(facultyid) references User_Faculty(userid)
);
The primary key for Course_Interest_group is not just interest_gid, but interest_gid, courseid, and facultyid.
There are several other instances of the same issue.
My question is, when referencing Course_Interest_group how can I reference just interest_gid? Is it possible? Should I change something?
I would like to keep the current Course_Interest_group pk of (interest_gid, courseid, facultyid) intact but I will modify it if needed.
my code
my output
If in the course_interest_group table interest_gid uniquely identifies each row in the table then interest_gid should be the primary key. Similarly, in the group_disforum if df_id uniquely identifies each row in the table then df_id should be the primary key. Modifying the primary keys of both these tables should solve the issue.
I think the way around for your question will be a TRIGGER to customize the data Integrity. You can create a before INSERT Trigger which will check first whether the data in your case (Course_Interest_group(interest_gid)). So basic structure of your Trigger will be like. Hope this may be a workwround.
SET SQLBL ON;
SET DEFINE OFF;
CREATE OR REPLACE TRIGGER group_disforum_tg BEFORE
INSERT OR
UPDATE
/*OF ig_id*/
ON group_disforum FOR EACH ROW
DECLARE lv_chck PLS_INTEGER;
BEGIN
SELECT COUNT(1)
INTO lv_chck
FROM Course_Interest_group
WHERE interest_gid = :new.interest_gid;
IF lv_chck = 0 THEN
RAISE_APPLICATION_ERROR(-20001,'Parent key (interest_gid) not found in group_disforum_tg',TRUE);
END IF;
END;
/
I have 4 tables
customer: CustomerID - primary key, name
Magazine: name - primary key, cost, noofissues
Newspaper: name - primary key, cost, noofissues
subscription: custID - references CustomerID of Customer, name, startdate, enddate
In the above, can I reference the name from subscription table to reference name from Magazine and name from Newspaper?
I have created the tables Customer, Newspaper and Magazine. I only need to create Subscription.
Can you do something like this?
CREATE TABLE subscription (
custID INT
CONSTRAINT subscription__custid__fk REFERENCES Customer( CustomerId ),
name VARCHAR2(50)
CONSTRAINT subscription__mag_name__fk REFERENCES Magazine( Name )
CONSTRAINT subscription__news_name__fk REFERENCES Newspaper( Name ),
startdate DATE
CONSTRAINT subscription__startdate__nn NOT NULL,
enddate DATE
);
Yes, you can and you will have two foreign keys on the same column pointing to different tables but if the value in the column is non-null then it will expect there to be a matching name in both the magazines table and the newspapers table - which is probably not what you are after.
Can you have a foreign key that asks can the value be in either exclusively in this table or that table (but not in both)? No.
But you can re-factor your database so you merge the newspapers and magazines tables into a single table (which you can then easily reference); like this:
CREATE TABLE customer (
CustomerID INT
CONSTRAINT customer__CustomerId__pk PRIMARY KEY,
name VARCHAR2(50)
CONSTRAINT customer__name__nn NOT NULL
);
CREATE TABLE Publications (
id INT
CONSTRAINT publications__id__pk PRIMARY KEY,
name VARCHAR2(50)
CONSTRAINT publications__name__nn NOT NULL,
cost NUMBER(6,2)
CONSTRAINT publications__cost__chk CHECK ( cost >= 0 ),
noofissues INT,
type CHAR(1),
CONSTRAINT publications__type__chk CHECK ( type IN ( 'M', 'N' ) )
);
CREATE TABLE subscription (
custID INT
CONSTRAINT subscription__custid__fk REFERENCES Customer( CustomerId ),
pubID INT
CONSTRAINT subscription__pubid__fk REFERENCES Publications( Id ),
startdate DATE
CONSTRAINT subscription__startdate__nn NOT NULL,
enddate DATE
);
If you are asking whether you can create a foreign key constraint on subscription that references either the newspaper table or the magazine table, the answer is no, you cannot. A foreign key must reference exactly one primary key.
Since magazine and newspaper have the same set of attributes, the simple option is to combine them into a single periodical table with an additional periodical_type column to indicate whether it is a magazine or a newspaper. You could then create your foreign key to the periodical table.
Although it probably won't make sense in this particular example, you could also have separate columns in subscription for magazine_name and newspaper_name and create separate foreign key constraints on those columns along with a check constraint that ensured that exactly one of the values was non-NULL. That might make sense if the two different parent tables had radically different attributes.
Not related to your question but as a general bit of advice, I wouldn't use the name as the primary key. In addition to being rather long, names tend to change over time and names aren't necessarily unique. I would use a different attribute for the key, potentially a synthetic primary key generated from a sequence.
I´ve got this table:
mysql> CREATE TABLE favorite food
-> (person_id SMALLINT UNSIGNED,
->food VARCHAR(20),
->CONSTRAINT pk_favorite_food PRIMARY KEY (person_id, food),
->CONSTRAINT fk_fav_food_person_id FOREIGN KEY (person_id)
->REFERENCES person (person_id)
->);
After execution i get the error 1064. Anybod any ideas what could be wrong?
MySQL Server 6.0
Table name should not have a whitespace in it. Make it something like favorite_food
By searching some possible response on Google, I found this thread on SO... The original table (which is the same as your, but with a nicer formatting) is:
CREATE TABLE favorite_food(
person_id SMALLINT UNSIGNED,
food VARCHAR(20),
CONSTRAINT pk_favorite_food PRIMARY KEY(person_id,food),
CONSTRAINT fk_fav_food_person_id FOREIGN KEY (person_id) REFERENCES person(person_id)
);
You probably don't have the person table, so the foreign key can't be created. (see the last line)
You have remove the _ in the table name (favorite food instead of favorite_food) which is not allowed.
We have a single table that we want to break up into a tree of tables based upon a particular source column. I wanted to try using a multi-column insert, but it seems that if I insert a blob into a sub table, I wind up with a foreign key constraint violation.
I don't think this violates the rules about multi-table inserts but I could be wrong...
I am hoping that someone could point me to some more in-depth resources around what is actually going on here, so that I can feel confident that whatever solution will work as part of a liquibase changeset on Oracle databases 9i -> 11g.
Hopefully Simplified Scenario
CREATE TABLE source (
pk NUMBER NOT NULL PRIMARY KEY,
type VARCHAR2(20) NOT NULL,
content VARCHAR2(20) NOT NULL
);
INSERT INTO source (pk,type,content) values (1,'two','n/a');
INSERT INTO source (pk,type,content) values (2,'one','Content');
CREATE TABLE dest (
pk NUMBER NOT NULL PRIMARY KEY,
type VARCHAR2(20) NOT NULL
);
CREATE TABLE dest_one (
pkfk NUMBER NOT NULL PRIMARY KEY,
data BLOB NOT NULL,
CONSTRAINT XFK1DEST_ONE FOREIGN KEY (pkfk) REFERENCES dest (pk)
);
CREATE TABLE dest_two (
pkfk NUMBER NOT NULL PRIMARY KEY,
CONSTRAINT XFK1DEST_TWO FOREIGN KEY (pkfk) REFERENCES dest (pk)
);
Source contains our original data. dest will be our parent table, with children dest_one and dest_two (which will contain information on things of type 'one' or 'two' respectively). Things of type one have content, but things of type two do not.
The Failed Attempt
INSERT ALL
WHEN 1=1 THEN INTO dest (pk,type) VALUES (pk,type)
WHEN type='one' THEN INTO dest_one (pkfk,data) VALUES (pk,content)
WHEN type='two' THEN INTO dest_two (pkfk) VALUES (pk)
SELECT pk,type,utl_raw.cast_to_raw(content) as content from source where type in ('one','two');
As previously mentioned, I wound up with a foreign key constraint violation here. To further illustrate that the blob was the issue I tried two seperate similar queries (below) realizing the one without the blob insert worked, but with the blob insert failed.
INSERT ALL
WHEN 1=1 THEN INTO dest (pk,type) VALUES (pk,type)
WHEN type='two' THEN INTO dest_two (pkfk) VALUES (pk)
SELECT pk,type,utl_raw.cast_to_raw(content) as content from source where type = 'two';
/* Successful */
INSERT ALL
WHEN 1=1 THEN INTO dest (pk,type) VALUES (pk,type)
WHEN type='one' THEN INTO dest_one (pkfk,data) VALUES (pk,content)
SELECT pk,type,utl_raw.cast_to_raw(content) as content from source where type = 'one';
/* ORA-02291: integrity constraint violated, no parent key */
Solution 1 - Traditional Inserts
INSERT INTO dest (pk,type) SELECT pk,type from source where type in ('one','two');
INSERT INTO dest_two (pkfk) SELECT pk from source where type = 'two';
INSERT INTO dest_one (pkfk,data) SELECT pk,utl_raw.cast_to_raw(content) from source where type = 'one';
One option I am considering is going back to multiple seperate insert statements, but unlike how I have stated them here, I'm concerned that I'll have to make sure I write my sub-table inserts to only attempt to insert those rows present in parent dest table... I need to do more research on how Liquibase handles multiple sql statements in the same changeset.
Solution 2 - Temporarily disabling foreign key constraints
ALTER TABLE dest_one DISABLE CONSTRAINT XFK1DEST_ONE;
INSERT ALL
WHEN 1=1 THEN INTO dest (pk,type) VALUES (pk,type)
WHEN type='one' THEN INTO dest_one (pkfk,data) VALUES (pk,content)
WHEN type='two' THEN INTO dest_two (pkfk) VALUES (pk)
SELECT pk,type,utl_raw.cast_to_raw(content) as content from source where type in ('one','two');
ALTER TABLE dest_one ENABLE CONSTRAINT XFK1DEST_ONE;
This is the solution I'm leaning toward. While disabling the foreign key on my blob table seems to make it work in my test environment (10g - 10.2.0.1.0), I'm not sure if I should also be disabling the foreign key on the non-blob table as well (due to how 9i, 11g, or other versions of 10g may behave). Any resources here too would be appreciated.
Thanks a bunch!
Another solution would be to defer the constraint evaluation until COMMIT. I suspect (but am not sure) that the multi-table insert is inserting rows in an order other than the one you expect and want. Recreate your constraints as follows:
ALTER TABLE DEST_ONE DROP CONSTRAINT XFK1DEST_ONE;
ALTER TABLE DEST_ONE
ADD CONSTRAINT XFK1DEST_ONE
FOREIGN KEY (pkfk) REFERENCES dest (pk)
INITIALLY DEFERRED DEFERRABLE;
ALTER TABLE DEST_TWO DROP CONSTRAINT XFK1DEST_TWO;
ALTER TABLE DEST_TWO
ADD CONSTRAINT XFK1DEST_TWO
FOREIGN KEY (pkfk) REFERENCES dest (pk)
INITIALLY DEFERRED DEFERRABLE;
This re-creates the constraints so that they can be deferred, and are deferred from the time they're created. Then try your original INSERT again.
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