- What is a proper naming convention for MySQL FKs?
user_id in messages table is a fk field so it has to make clear which id is (user_id) a fully-self-explaining naming convention, in my opinion, could be: fk_[referencing table name]_[referencing field name]_[referenced table name]_[referenced field name] i e : `fk_messages_user_id_users_id`
- Differences between foreign key and constraint foreign key
CREATE TABLE Orders ( O_Id int NOT NULL, OrderNo int NOT NULL, P_Id int, PRIMARY KEY (O_Id), CONSTRAINT fk_PerOrders FOREIGN KEY (P_Id) REFERENCES Persons(P_Id) ) Also, from CREATE TABLE (Transact-SQL) one can see that [ CONSTRAINT constraint_name ] is optional
- How can I list all foreign keys referencing a given table in SQL Server . . .
Works great! It'd be even better if you: a) prefix all Column Names with "Fk" "Key"), b) suffix all Column Names with "Name", c) remove underscores, d) add KeyTableSchemaName, e) add default order by: KeyTableSchemaName, KeyTableName, KeyColumnName, FkTableSchemaName, FkTableName, FkName, and f) change Column order to: KeyTableSchemaName, KeyTableName, KeyColumnName, FkTableSchemaName
- List of foreign keys and the tables they reference in Oracle DB
WITH reference_view AS (SELECT a owner, a table_name, a constraint_name, a constraint_type, a r_owner, a r_constraint_name, b column_name FROM dba_constraints a, dba_cons_columns b WHERE a owner = b owner AND a constraint_name = b constraint_name AND constraint_type = 'R'), constraint_view AS (SELECT a owner a_owner, a table_name, a column_name
- How to find foreign key dependencies in SQL Server?
select fk_table = fk table_name, fk_column = cu column_name, pk_table = pk table_name, pk_column = pt column_name, constraint_name = c constraint_name from information_schema referential_constraints c inner join information_schema table_constraints fk on c constraint_name = fk constraint_name inner join information_schema table_constraints pk
- sql - Foreign Key to non-primary key - Stack Overflow
Consider the case of a Customer table with a SSN column (and a dumb primary key), and a Claim table that also contains a SSN column (populated by business logic from the Customer data, but no FK exists) The design is flawed, but has been in use for several years, and three different applications have been built on the schema
- SQL Server Error: % is not a constraint. Could not drop constraint . . .
Msg 3728, Level 16, State 1, Line 1 'fk_gr_res_resources' is not a constraint Msg 3727, Level 16, State 0, Line 1 Could not drop constraint See previous errors Because the FK constraint does not exist! Are you sure that Information is the right schema name and not dbo? 1 This SQL will prove that the FK does not exist:
- How to create a foreign key in phpmyadmin - Stack Overflow
CREATE TABLE products( prd_id int not null auto_increment primary key, prd_name varchar(355) not null, prd_price decimal, cat_id int not null, FOREIGN KEY fk_cat(cat_id) REFERENCES categories(cat_id) ON UPDATE CASCADE ON DELETE RESTRICT )ENGINE=InnoDB; Create a vendors table and modify products table:
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