I am attempting to set up a database with partitions, however I am running into an error when creating the activity table. The 3 Table CREATEs (without the actual data) are as follows:
CREATE TABLE collection (
id SERIAL PRIMARY KEY
);
CREATE TABLE asset (
id SERIAL,
collection_id INT,
CONSTRAINT fk_collection
FOREIGN KEY(collection_id)
REFERENCES collection(id),
CONSTRAINT asset_pkey PRIMARY KEY(id, collection_id)
)PARTITION BY LIST(collection_id);
CREATE TABLE activity(
id SERIAL,
collection_id INT,
CONSTRAINT fk_collection
FOREIGN KEY(collection_id)
REFERENCES collection(id),
CONSTRAINT activity_pkey PRIMARY KEY(id, collection_id),
asset_id INT,
CONSTRAINT fk_asset
FOREIGN KEY(asset_id)
REFERENCES asset(id)
) PARTITION BY LIST(collection_id);
ERROR: there is no unique constraint matching given keys for referenced table "asset"
SQL state: 42830
My understanding of the error is that foreign keys must be unique. Because I must add collection_id as a primary key to partition item, I cannot also designate id as unique. When I attempt to make id unique, this is what happens:
ALTER TABLE asset
ADD CONSTRAINT u_id UNIQUE (id);
ERROR: unique constraint on partitioned table must include all partitioning columns
DETAIL: UNIQUE constraint on table "asset" lacks column "collection_id" which is part of the partition key.
SQL state: 0A000
Even if I successfully add the UNIQUE constraint on id and collection_id, it continues to throw me SQL state: 42830. Do I have to restructure my data or is there a better way to go about this that I'm not thinking of?
Would it be enough to merge the foreign keys on asset into one composite key, or does that violate some other constraint of your data?
CREATE TABLE activity(
id SERIAL,
collection_id INT,
asset_id INT,
CONSTRAINT activity_pkey PRIMARY KEY(id, collection_id),
CONSTRAINT fk_asset_collection
FOREIGN KEY(asset_id, collection_id)
REFERENCES asset(id, collection_id)
) PARTITION BY LIST(collection_id);
Related
I'm creating a SQL table in VS that stores what rooms each client is, So the table has RoomId (int) and UserID (int).
Because I only want to add to the table only rooms and clients that exist they are both keys that have a foreign key to 2 tables, one that stores RoomID and Name and another that stores Client ID and Name.
Room and UserId tables:
CREATE TABLE [dbo].[UsersInRoomsTable]
(
RoomId INT NOT NULL,
UserId INT NOT NULL,
CONSTRAINT PK_RS PRIMARY KEY(RoomId, UserId),
CONSTRAINT [fk_room] FOREIGN KEY([RoomId]) REFERENCES [dbo].[RoomsTable]([RoomId]),
CONSTRAINT [fk_user] FOREIGN KEY ([UserId]) REFERENCES [dbo].[UserInfoTable] ([UserId])
);
Table that stores all the users:
CREATE TABLE [dbo].[UserInfoTable]
(
[UserName] NVARCHAR (50) NOT NULL,
[UserId] INT NOT NULL,
CONSTRAINT [PK_roomuser] PRIMARY KEY CLUSTERED ([UserName] ASC, [UserId] ASC)
);
Table that stores all the rooms
CREATE TABLE [dbo].[RoomsTable]
(
[RoomId] INT NOT NULL,
[RoomName] NVARCHAR (50) NOT NULL,
PRIMARY KEY CLUSTERED ([RoomId] ASC)
);
Everything works except the last line in the Rooms and users table:
CONSTRAINT [fk_user] FOREIGN KEY ([UserId]) REFERENCES [dbo].[UserInfoTable] ([UserId])
When I try to Update the table I get an error SQL71516:
SQL71516: The referenced table '[dbo].[UserInfoTable]' contains no primary or candidate keys that match the referencing column list in the foreign key.
If the referenced column is a computed column, it should be persisted
How can I solve this problem and what is causing it?
Edit: I think I know what is code is colliding: For some reason I can not have a foreign key connecting to a key that contains 2 indexes IE: fk_user is a Fk to table UserInfoTable that has 2 keys (UserID and UserName)
is there a way to pass this obstacle?
The columns of a foreign key have to match the columns they reference by number, type and order.
You have a primary key on userinfotable of (username, userid). But in usersinroomstable you are trying to let the foreign key (userid) to reference that. The number of columns doesn't match, so the foreign key cannot be added.
Presumably the username shouldn't really be part of the primary key of userinfotable and got there by accident. Remove it from the primary key constraint.
Or, if username has to be in the primary key, add such a column to the table usersinroomstable and add it to the foreign key constraint.
My problem is that i have two tables with each table having a foreign key to the other table.
Each time , i execute the SQL file containing the creation of the two tables, it gives me an error that he doesn't find the other table. I'm working with sqlplus to execute the sql file.
Here's an example of SQL file i tried with :
create table A(
Age number(3),
name number(3) constraint A_FK references B(name))
/
create table B(
Age number(3) constraint B_FK references A(Age),
name number(3))
And even if i reverse the order, it gives the same error.
Thanks for help.
This is a problem of cycles in foreign keys. One method is to add all foreign keys after table creation (as I think the other answers propose).
You can also just do that for the first table:
create table A (
Age number(3) primary key,
name number(3)
);
create table B (
name number(3) primary key,
Age number(3),
constraint B_FK foreign key (age) references A(Age)
);
alter table B add constraint A_FK foreign key (name) references B(name);
Here is a db<>fiddle.
Notes:
Foreign keys should reference primary keys, so I added that declaration as well.
I recommend making the primary key the first column in the table.
You can also define the constraint inline for one of the tables (i.e. age number(3) constraint b_fk references a(age)).
The table column(s) that is referred by a foreign key must exist at the time when the constraint is created. Since you have some kind of cyclic reference between the tables, you need to do this in three steps:
first create one table without the foreign key
create the second table (with its foreign key)
finally add the foreign key to the first table with an alter table statement
You also need the referred column to have a unique or primary key constraint set up, otherwise you would get error ORA-02270: no matching unique or primary key for this column-list.
create table A(
age number(3) primary key,
name number(3)
);
create table B(
age number(3) constraint B_FK references A(Age),
name number(3) primary key
);
alter table A add constraint A_FK foreign key (name) references B(name);
Demo on DB Fiddle
Side note: I am quite suspicious about your sample structure, but this could be because your oversimplified it in the question.
It fails because the reference table doesn't exist yet.
Create the tables without the key first. Then drop one and recreated it with the reference. Then drop the 2nd and recreate it with the reference.
Create table first and then ADD the CONSTRAINT
ALTER TABLE A
ADD FOREIGN KEY (name) REFERENCES B(name);
ALTER TABLE B
ADD FOREIGN KEY (age) REFERENCES A(age);
For example
create table Equipment (
Equipmenttype nvarchar(1,
Description nvarchar(10),
Primary Key (Equipmenttype)
)
Create table Room (
RoomID nvarchar(8),
Capacity numeric(3),
Roomtype(fk,nvarchar(2)
)
I want to create the following table...
create table RoomEquipment(
(RoomID here)
(Equipmenttype here)
but Equipmenttype is not a primary key.
You can create foreign key on columns that are PK or Unuque:
So you have to create a unique index on RoomID:
CREATE UNIQUE INDEX UI_Room_RoomID ON dbo.Room(RoomID);
Now you can create a foreign key in table RoomEquipment.
A FOREIGN KEY constraint does not have to be linked only to a PRIMARY KEY constraint in another table; it can also be defined to reference the columns of a UNIQUE constraint in another table.
Source: Foreign Key to non-primary key
Equipmenttype is a primary key, in its own table Equipment, and RoomID should be a primary key for Room.
So RoomEquipment is a standard many-to-many relationship table.
I have two tables:
Article
Subscription
In the Article table I have two columns that make up the primary key: id, sl. In the Subscription table I have a foreign key 'idsl`.
I use this constraint :
constraint FK_idsl
foreign key (idsl) references CSS_SubscriptionGroup(id, sl)
But when I run the query, I getting this error:
Number of referencing columns in foreign key differs from number of referenced columns, table X
In Article Table I have two fields that are the primary key: id,sl. In the Subscription Table I have a foreign key 'idsl`
This design is broken - it is apparent that the composite primary key in Article(id, sl) has been mangled into a single compound foreign key in table Subscription. This isn't a good idea.
Instead, you will need to change the design of table Subscription to include separate columns for both id and sl, of the same type as the Article Table, and then create a composite foreign key consisting of both columns, referencing Article in the same order as the primary key, e.g:
CREATE TABLE Article
(
id INT NOT NULL,
sl VARCHAR(50) NOT NULL,
-- Other Columns
CONSTRAINT PK_Article PRIMARY KEY(id, sl) -- composite primary key
);
CREATE TABLE Subscription
(
-- Other columns
id INT NOT NULL, -- Same type as Article.id
sl VARCHAR(50) NOT NULL, -- Same type as Article.sl
CONSTRAINT FK_Subscription_Article FOREIGN KEY(id, sl)
REFERENCES Article(id, sl) -- Same order as Article PK
);
Edit
One thing to consider here is that by convention a column named table.id or table.tableid should be unique, and is the primary key for the table. However, since table Article requires an additional column sl in the primary key, it implies that id isn't unique.
correct syntax for relation:
CONSTRAINT FK_OtherTable_ParentTable
FOREIGN KEY(OrderId, CompanyId) REFERENCES dbo.ParentTable(OrderId, CompanyId)
You must try like this:
constraint FK_idsl foreign key (id,sl) references CSS_SubscriptionGroup(id,sl)
I have a composite primary key in 1 table in oracle. I want to create a foreign key for one table entry in my second table that references the composite primary key in the first table. I am getting the error ORA-02256. Any thoughts on how I can enter this?
CREATE TABLE groupspersonx (
personid number,
groupid number,
CONSTRAINT pk_persongroupid PRIMARY KEY(personid, groupid)
);
CREATE TABLE restrictedgroups (
groupid number,
name varchar2(50),
dateadded date,
since date,
notes varchar2(1024),
CONSTRAINT pk_groupid PRIMARY KEY(groupid),
CONSTRAINT fk_persongroup FOREIGN KEY(groupid) REFERENCES groupspersonx(personid, groupid)
);
The error is because the FOREIGN KEY is one column, but you're trying to supply two columns as the parent. There's no need to tie to the composite key, because the restrictedgroups doesn't have a personid column...
You also have the relationship backwards - use:
CREATE TABLE restrictedgroups (
groupid number,
name varchar2(50),
dateadded date,
since date,
notes varchar2(1024),
CONSTRAINT pk_groupid PRIMARY KEY(groupid)
);
CREATE TABLE groupspersonx (
personid number,
groupid number,
CONSTRAINT pk_persongroupid PRIMARY KEY(personid, groupid),
CONSTRAINT fk_persongroup FOREIGN KEY(groupid) REFERENCES restrictedgroups(groupid)
);
I would add a foreign key constraint for whatever table the personid would be coming from.
CREATE TABLE groupspersonx(
personid number, groupid number,
CONSTRAINT pk_persongroupid PRIMARY KEY(personid, groupid));
CREATE TABLE restrictedgroups (
pid number,
groupid number,
name varchar2(50),
dateadded date,
since date,
notes varchar2(1024),
CONSTRAINT pk_groupid PRIMARY KEY(groupid),
CONSTRAINT fk_persongroup FOREIGN KEY(pid,groupid) REFERENCES groupspersonx(personid, groupid));
* number of references columns is equals with foreign key columns
Whenever you want to create a composite primary key or unique constraint on a column, you can't give reference in another table.
for ex.
sql>create table t1( a number,b number,c number ,primary key(a,b,c));
table created.
sql>create table g1(a number constraint con_fg references t1(a));
ERROR at line 1:
ORA-02270: no matching unique or primary key for this column-list
Here t1 is parent table and g1 is child table. The child table can contains duplicate values in one column. So oracle will not allow that table of column.
See also
SQL>select constraint_name,constraint_type from user_constraints where table_name='T1';
CONSTRAINT_NAME C
------------------------------ -
SYS_C005822 P
So, here also the only constraint for all three columns i.e a,b,c in t1 table.
That's why you can't create a foreign on composite primary key or composite unique constraint
You can't use:
CONSTRAINT fk_persongroup FOREIGN KEY(groupid) REFERENCES groupspersonx(personid, groupid)
Change that too:
CONSTRAINT fk_persongroup FOREIGN KEY(groupid) REFERENCES groupspersonx(groupid)
That should work.