PDF (US Ltr)
- 35.1Mb
PDF (A4)
- 35.2Mb
Man Pages (TGZ)
- 256.4Kb
Man Pages (Zip)
- 361.2Kb
Info (Gzip)
- 3.4Mb
Info (Zip)
- 3.4Mb
Search Results
https://dev.mysql.com/doc/refman/5.7/en/create-table-foreign-keys.html
MySQL supports foreign keys, which permit cross-referencing related data across tables, and foreign key constraints, which help keep the related data consistent. A foreign key relationship involves a parent table that holds the initial column ...If ...The CONSTRAINT symbol value, if defined, must be unique in the ...
https://dev.mysql.com/doc/refman/5.7/en/ansi-diff-foreign-keys.html
In an SQL statement that inserts, deletes, or updates many rows, foreign key constraints (like unique constraints) are checked row-by-row. When performing foreign key checks, InnoDB sets shared row-level locks on child or parent records that it must ...(Although you can write an ON DELETE or ON UPDATE clause as part of the REFERENCES clause, it is also ignored.) This syntax creates a column; it does not create any sort of index or ...
https://dev.mysql.com/doc/refman/5.7/en/example-foreign-keys.html
MySQL supports foreign keys, which permit cross-referencing related data across tables, and foreign key constraints, which help keep the related data consistent. A foreign key relationship involves a parent table that holds the initial column ...To ...
https://dev.mysql.com/doc/refman/5.7/en/constraint-foreign-key.html
Foreign keys let you cross-reference related data across tables, and foreign key constraints help keep this spread-out data consistent. MySQL supports ON UPDATE and ON DELETE foreign key references in CREATE TABLE and ALTER TABLE statements. For ...
https://dev.mysql.com/doc/refman/5.7/en/foreign-key-optimization.html
That way, each small table can have a primary key for fast lookups of its data, and you can query just the set of columns that you need using a join operation. If a table has many columns, and you query many different combinations of columns, it ...
https://dev.mysql.com/doc/refman/5.7/en/partitioning-limitations-partitioning-keys-unique-keys.html
This section discusses the relationship of partitioning keys with primary keys and unique keys. The rule governing this relationship can be expressed as follows: All columns used in the partitioning expression for a partitioned table must be part ...These rules also apply to existing nonpartitioned tables that you wish to partition using ALTER TABLE ...
https://dev.mysql.com/doc/refman/5.7/en/information-schema-innodb-sys-foreign-table.html
The INNODB_SYS_FOREIGN table provides metadata about InnoDB foreign keys, equivalent to the information from the SYS_FOREIGN table in the InnoDB data dictionary. The INNODB_SYS_FOREIGN table has these columns: ID The name (not a numeric value) of ...For related usage information and examples, see Section 14.16.3, “InnoDB INFORMATION_SCHEMA System ...
https://dev.mysql.com/doc/refman/5.7/en/glossary.html
child table In a foreign key relationship, a child table is one whose rows refer (or point) to rows in another table with an identical value for a specific column. The values in the child table can prevent delete or update operations on the parent ...MySQL can build a hash index on a prefix of any length of the key defined for the B-tree, depending on the pattern of searches against the ...
https://dev.mysql.com/doc/refman/5.7/en/information-schema-innodb-sys-foreign-cols-table.html
The INNODB_SYS_FOREIGN_COLS table provides status information about the columns of InnoDB foreign keys, equivalent to the information from the SYS_FOREIGN_COLS table in the InnoDB data dictionary. The INNODB_SYS_FOREIGN_COLS table has these ...For ...
https://dev.mysql.com/doc/refman/5.7/en/constraint-primary-key.html
Normally, errors occur for data-change statements (such as INSERT or UPDATE) that would violate primary-key, unique-key, or foreign-key constraints. MySQL supports an IGNORE keyword for INSERT, UPDATE, and so forth. If you use it, MySQL ignores ...