A declarative mechanism such as a check or foreign key that enforces some data integrity rule in a database.

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10
votes
5answers
683 views

Why does this UPDATE fail with a unique key constraint violation?

I'm an "accidental" DBA, relatively inexperienced and baffled by this problem. Running MS SQL Server 2012. The problem is with this UPDATE statement: UPDATE dbo.tAccts SET Ticket ...
0
votes
1answer
110 views

How to add a check constraint in Postgres without locking the table?

I would like to add a check constraint to a very large table. Something like: ALTER TABLE accounts ADD CONSTRAINT "nonnegative_balance" CHECK balance >= 0; Unfortunately Postgres (9.3, at least) ...
0
votes
1answer
58 views

is_not_trusted = 1 after Error-Free WITH CHECK CHECK CONSTRAINT

I'd like SQL Server 2005 SP4 to trust a certain foreign key constraint. Executing an ALTER TABLE statement that enables + checks the constraint returns Command(s) completed successfully yet sys....
0
votes
1answer
44 views

Modify table constraint in PostgreSQL

Say I have a constraint ALTER TABLE distributors ADD CONSTRAINT zipchk CHECK (char_length(zipcode) = 5); that needs to be modified so that zipcode length is 6. Do I have the drop the constraint ...
8
votes
2answers
144 views

SQL Server equivalent of Oracle USING INDEX clause

Is there a SQL Server 2008 equivalent of the USING INDEX clause in Oracle? Specifically for the construct: CREATE TABLE c(c1 INT, c2 INT); CREATE INDEX ci ON c (c1, c2); ALTER TABLE c ADD CONSTRAINT ...
0
votes
1answer
43 views

Adding multiple constraints

I am trying to add constraints and I think i have an error in the code as its saying i cant add mutlple constrints. What is best way to add mutlple constraints I am using MSQL Server 2008 r2 CREATE ...
2
votes
0answers
55 views

Any drawbacks to referencing multiple tables from a single column?

I'm working on a system with the following entities: Projects Sections Activities There is one important constraint that needs to be enforced: Activities are always part of one project. ...
1
vote
1answer
36 views

What is the best approach to find all fields that has (Foreign Key and Primary Key) constraints in a Mysql database?

I have a mysql database that has 250 tables. I would like to run a query to retrieve: tableName ; FieldName ; ConstaintName (Primary or foreign key). I could use information_schema....
0
votes
1answer
26 views

Assign value to a field after checking a condition

I have this query: ALTER TABLE MERCHANTS ADD COLUMN merchant_image bytea, ADD COLUMN merchant_logo bytea, ADD COLUMN merchant_address VARCHAR(100), ADD COLUMN merchant_phone VARCHAR(50), ...
2
votes
1answer
1k views

How to set unique columns combination

see this table: CREATE TABLE IF NOT EXISTS `default_messages_users` ( `id` int(11) NOT NULL AUTO_INCREMENT, `message_id` int(11) NOT NULL, `owner_user_id` int(11) NOT NULL, `to_user_id` ...
0
votes
0answers
13 views

Unique attributes as a group [duplicate]

create table test (a int, b int); I want to make a and b be unique, but as a whole. Example: a b - - 1 1 1 2 - this is ok, because even if the previous entry was 1, the b value is different 2 1 - ...
1
vote
1answer
35 views

Duplicate check constraint on multiple tables?

I have an integer value for a data to be included into two or three tables, Say it is part no. The integer value of part no must be between 1 to 8. I want to add that constraint into the tables. ...
0
votes
0answers
16 views

How to use Domains in oracle database

I am trying to learn about domains. As far as i understand, domains are user defined "types" that describe restrictions of its value. But how would i assign and use a domain in a given table in an ...
17
votes
4answers
456 views

Entity relationship problem

I have 4 tables related like this (it's an example): Company: ID Name CNPJ Department: ID Name Code ID_Company Classification: ID Name Code ID_Company Workers: Id Name Code ID_Classification ...
1
vote
1answer
53 views

Constrain/limit certain records in sql table definitions

Let's say I have posts on which users can leave a comment. And I want to limit the amount of comments to a certain post to 10, is it possible to add such constraint/restriction to the table? My guess ...
1
vote
2answers
569 views

Performance of single vs multiple column unique constraint

I'm using PostgreSQL 9.3. I want to understand if I have an option to make a constraint unique across the entire table vs. unique across a subset of the table (i.e. by using 2 columns in the unique ...
1
vote
1answer
54 views

Indirect constraints (foreign keys amongst three/four tables) [duplicate]

I have the next layout of tables: table COMPANY: - primary key pk_company table USERS: - primary key pk_users, - foreign key (fk_company) references COMPANY (pk_company) table GROUPS: <br> - ...
3
votes
1answer
160 views

Constrains relationship

I have the following design. Each user has it's own contacts, it's own hosts and assign those to a domain which belongs only to him. I want to insure that the host you assign to the domain belongs ...
11
votes
3answers
389 views

Constraint to enforce “at least one” or “exactly one” in a database

Say we have users and each user can have multiple email addresses CREATE TABLE emails ( user_id integer, email_address text, is_active boolean ) Some sample rows user_id | ...
5
votes
2answers
778 views

Conditional Foreign Key Relationship

I currently have a foreign key between two entities, and I would like to make that relation conditional to the entityType of one of the tables. Here's the hierachy of tables, this is done via FK ...
1
vote
1answer
30 views

Can I enforce one field being dependent on another?

I would like to know if it's possible to have two fields (in this case bits) in the same table where one is dependent on another. For example Check2 may only be true if Check1 is true. Note: I'm ...
9
votes
2answers
4k views

How can I help SQL Server recognize my indexed view column is NOT NULL-able?

I have the following indexed view defined in SQL Server 2008 (you can download a working schema from gist for testing purposes): CREATE VIEW dbo.balances WITH SCHEMABINDING AS SELECT user_id ...
1
vote
1answer
64 views

Enforce a single NULL end date per foreign key value using an index

I want to implement a Check Constraint across a date range and foreign key. I have a table created as: Primary Key Foreign Key DateStart DateEnd The ForeignKey can appear many times in the table ...
1
vote
1answer
50 views

Using REGEX_LIKE to Implement a Check Constraint

Background I am working on the database design for an application that tracks information about database development projects at my company. The project management office (PMO) assigns a psued-...
0
votes
1answer
96 views

Create an “int” column forced between 0 and 3

I would like to create a table with one column that would be of type "integer", and locked between 0 and 3. Is this possible? My goal would be to have this column so that I could just execute a ...
1
vote
1answer
609 views

Adding foreign keys constraint on databases used

We have a server with about 20 databases, all duplicates of the same original db, and we just noticed the original is missing all the foreign keys constraint for some unknown reason. So of course all ...
5
votes
1answer
430 views

How to enforce a constraint over multiple tables?

I have the following five tables: PRODUCT FEATURE PROVIDER PROVIDER_PRODUCT PROVIDER_FEATURE The logic is as follows: A generic PRODUCT can have one or more FEATUREs. There are different ...
3
votes
1answer
155 views

Enabling Constraint Silently Fails

Why would SQL Server silently fail to re-enable a foreign key constraint? I recently attempted to re-enable a number of constraints using ALTER TABLE. Most enabled successfully; however, minority of ...
2
votes
1answer
83 views

Can Indexes mitigate untrusted Constraint

I using sp_blitz and found two tables that have foreign keys that is untrusted. tried to enable the trust with: ALTER TABLE MyTableName WITH CHECK CHECK CONSTRAINT MyConstraintName; GO But got this ...
3
votes
3answers
166 views

Cap on number of rows matching a condition in Postgres

Say I have a db schema like this user_id text photo_id text date_created timestamp and I want to enforce a constraint that says "a user can only have 30 photos". A naive way to implement this would ...
0
votes
1answer
58 views

Is unique index combined with a “not null” constraint equivalent to a PK constraint?

I have these legacy table definitions (from here): CREATE TABLE [dbo].[JobItems] ( [ItemId] UNIQUEIDENTIFIER NOT NULL, -- lots of other columns CONSTRAINT [PrimaryKey_GUID_HERE] ...
2
votes
1answer
164 views

Foreign Key Constraint over two tables

I am trying to put the following entity-model into practice: We have a list of Payments, each Payment belongs to a certain store and is of a certain payment type (e.g. 10€ maintenance cost in Store1,...
2
votes
1answer
180 views

Multi-column uniqueness constraint, checking a field has one of two values

I'd like to enforce that only one row in a database matches value A in column 1, and either value B or value C in column 2. A small example create table builders ( id text serial ); create table ...
3
votes
1answer
492 views

Postgres 9.3 - deletes terribly slow for 10 minutes after dropping indexes/constraints

If I run a script which drops indexes (17 of them, CONCURRENTLY makes no difference except that without it I get the occasional deadlock), then constraints (20 constraints on 18 tables) and then run a ...
0
votes
0answers
74 views

MariaDB error on alter table - table removed - constraint name is blocked

Today, we experienced a strange behavior in 5.5.41-MariaDB (InnoDB): An ALTER TABLE (add constraint) statement failed with error (mysql server has gone away after that). Then the database table ...
0
votes
1answer
25 views

Verify conditions before creating a constraint

I've taken over an application database that has been grown from an Access db. As such, the database is in need of some significant refactoring. The first step that I'm planning is adding a number of ...
0
votes
2answers
36 views

Basic SQL question about setting constraints

In code such as the following, what is the need to write constraint pk_dept primary key (deptno) if just simply primary key (deptno) works? Is pk_dept something the database uses internally, since it ...
1
vote
1answer
520 views

Can't add a foreign key constraint in a table on Postgresql

I'm trying to add a foreign key of "prefectures" table in "centresdevote" table. But I'm having this error while trying to add a foreign key to "centresdevote" table. I had no problem adding foreign ...
2
votes
1answer
49 views

Detect circular relations in a distribution table

I have the following two tables, that will define distribution rates from items on table A to other items on table A (I think I can say B defines a many-to-many relationship for A with itself). ...
11
votes
2answers
7k views

What does 'ibfk' stand for in MySQL?

If I create a foreign key constraint for table 'photos' in phpmyadmin, I later see that the constraint is named 'photos_ibfk_1', and the next constraint is called 'photos_ibfk_2', etc. From this I ...
0
votes
1answer
73 views

SQL Server transactional replication issue with database

We have on the server a database and we want to replicate a database on another server. we've set a transactional replication, but we have issues with the default constraints on the tables: On the ...
2
votes
0answers
23 views

SQLITE Foreign key has to be re-added? [closed]

Currently I have a mysql database on my computer which I convert to sqlite database. On the sqlite database, I have transaction_detail table with a foreign key to transaction_master table. The ...
17
votes
1answer
6k views

PostgreSQL EXCLUDE USING error: Data type integer has no default operator class

In PostgreSQL 9.2.3 I am trying to create this simplified table: CREATE TABLE test ( user_id INTEGER, startend TSTZRANGE, EXCLUDE USING gist (user_id WITH =, startend WITH &&) ); ...
0
votes
0answers
154 views

What order do foreign key constraints run in? Why does my foreign key not work after import?

I have two tables tags and tag_memberships in a PostgreSQL database. On the tag_memberships table, I have two constraints. The first is this: ALTER TABLE tag_memberships ADD CONSTRAINT ...
2
votes
1answer
64 views

Can column uniqueness be commutative?

I have a table in a Postgres DB where col1 and col2 are foreign keys referring to the same column. I want only unique combinations of (col1, col2), i.e. if (1,2) is entered then (2,1) should be ...
0
votes
3answers
2k views

check key if exists in other table without fk constraint

Lets say i have: table a (id_a int); table b (id_b int, id_a int); I want to check if b.id_a exists in "a" before a new row in "b" will be inserted. Normally I would just add a fk constraint on b....
0
votes
1answer
104 views

How can we drop a constraint without losing the automatically created index?

How can we drop a constraint without losing the automatically created index? If it's possible using a single query.
2
votes
1answer
798 views

Deferrable Foreign Key Constraints

What are the consequences of making a foreign key constraint DEFERRABLE INITIALLY IMMEDIATE instead of NONDEFERRABLE? This answer on StackOverflow mentions the performance impact that comes with no ...
2
votes
0answers
50 views

Compound key that only allows nulls if they are null in the referenced table

I want to create a compound foreign key constraint that only allows a null value in one of the columns if there is a matching row with a null value in the referenced table. Additionally, the ...
0
votes
0answers
97 views

Cleaning up orphaned metadata in information_schema

OK - so the server (Percona 5.6 in this case) 'went away' in the middle of declaring a constraint like so: alter table mytable add constraint fk_mytable_myothertable foreign key (myothertable_id) ...