- 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
- 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 LIKE UPPER ('SYS') AND a owner = b owner AND a constraint_name = b constraint_name AND constraint_type = 'R'), constraint_view AS (SELECT a owner a
- 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
- mysql - Add Foreign Key to existing table - Stack Overflow
@Erin Geyer, its been 2 years or so, but the 'Cannot add or update a child row: a foreign key constraint fails' usually happens because of data inconsistency between a newly added column which you have set as a foreign key reference to a column on another table which does not yet have the data on the column it refers to
- 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`
- How do I drop a foreign key in SQL Server? - Stack Overflow
The object 'Company_CountryID_FK' is dependent on column 'CountryID' Msg 4922, Level 16, State 9, Line 2 ALTER TABLE DROP COLUMN CountryID failed because one or more objects access this column I have tried this, yet it does not seem to work: alter table company drop foreign key Company_CountryID_FK; alter table company drop column CountryID;
- How do I create a foreign key in SQL Server? - Stack Overflow
Alter Table ForeignKeyTable Add constraint `ForeignKeyTable_ForeignKeyColumn_FK` `Foreign key (ForeignKeyColumn)` references `PrimaryKeyTable (PrimaryKeyColumn)` i e Alter Table tblEmployee Add constraint tblEmployee_DepartmentID_FK foreign key (DepartmentID) references tblDepartment (ID)
- 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
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