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https://dev.mysql.com/doc/refman/8.4/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. This following example relates parent and child tables through a single-column foreign ...A foreign key relationship involves a parent table that holds the initial column values, and a child table with column values that reference the parent column ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-online-ddl-operations.html
ALTER TABLE tbl1 ADD CONSTRAINT fk_name FOREIGN KEY index (col1) REFERENCES tbl2(col2) referential_actions; Dropping a foreign key constraint ALTER TABLE tbl DROP FOREIGN KEY fk_name; Dropping a foreign key can be performed online with the ...
https://dev.mysql.com/doc/refman/8.4/en/server-system-variables.html
Note Although the authentication_policy system variable places certain constraints on the authentication-related clauses of CREATE USER and ALTER USER statements, a user who has the AUTHENTICATION_POLICY_ADMIN privilege is not subject to these ...
https://dev.mysql.com/doc/refman/8.4/en/show-create-table.html
row *************************** Table: t Create Table: CREATE TABLE `t` ( `id` int NOT NULL AUTO_INCREMENT, `s` char(60) DEFAULT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci SHOW CREATE TABLE displays ... SHOW CREATE TABLE tbl_name Shows the CREATE TABLE statement that creates the named ...
https://dev.mysql.com/doc/connectors/en/connector-python-example-ddl.html
All DDL (Data Definition Language) statements are executed using a handle structure known as a cursor. The following examples show how to create the tables of the Employee Sample Database. In a MySQL server, tables are very long-lived objects, and ...
https://dev.mysql.com/doc/connector-python/en/connector-python-example-ddl.html
All DDL (Data Definition Language) statements are executed using a handle structure known as a cursor. The following examples show how to create the tables of the Employee Sample Database. In a MySQL server, tables are very long-lived objects, and ...
https://dev.mysql.com/doc/refman/8.4/en/identifier-length.html
For constraint definitions that include no constraint name, the server internally generates a name derived from the associated table name. For example, internally generated foreign key and CHECK constraint names consist of the table name plus _ibfk_ ... The following table describes the maximum length for each type of ...
https://dev.mysql.com/doc/internals/en/replication-correct.html
Specifically: If the slave has a uniqueness constraint (PK or UK), then uniqueness must be guaranteed before a row is inserted on the slave. This can be done, for example, through the following strategies: Have a uniqueness constraint (UK or PK) on ... In addition to what we guarantee in (P-rpl-correct), we also guarantee correct replication in the following scenarios: (P-rpl-different-file-system-case-sensitivities) TODO: allowed differences in file system case sensitivity (P-rpl-different-versions) Replication shall be correct even if master has version a.b.c and slave has version A.B.C, where A.B.C ≥ a.b.c and A ≤ ...
https://dev.mysql.com/doc/refman/8.4/en/mysql-cluster-options-variables.html
--ndb-deferred-constraints=[0|1] Command-Line Format --ndb-deferred-constraints System Variable ndb_deferred_constraints Scope Global, Session Dynamic Yes SET_VAR Hint Applies No Type Integer Default Value 0 Minimum Value 0 Maximum Value 1 Controls ... This section provides information about MySQL server options, server and status variables that are specific to NDB ...
https://dev.mysql.com/doc/refman/8.4/en/numeric-type-syntax.html
For integer data types, M indicates the minimum display width. Display width is unrelated to the range of values a type can store, as described in Section 13.1.6, “Numeric Type Attributes”. For floating-point and fixed-point data types, M is ...