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You could use a two-column primay key in mysql ...PRIMARY KEY(id_a, id_b)... but I prefer using a two-column unique index, and having an auto-increment primary key field. Share Improve this answer
To create a composite index during table creation, you use the following statement: CREATE TABLE table_name ( c1 data_type PRIMARY KEY, c2 data_type, c3 data_type, c4 data_type, INDEX index_name (c2,c3,c4) ); Code language: SQL (Structured Query Language) (sql) In this syntax, the composite index consists of three columns c2, c3, and c4.
MySQL can create composite indexes (that is, indexes on multiple columns). An index may consist of up to 16 columns. For certain data types, you can index a prefix of the column (see Section 10.3.5, “Column Indexes”).
Mysql auto create an index for composite keys. Depending on your queries, you may have to create separate index for individual column in the composite key. If you are using mysql workbench, you can manually right click the schema and click on edit to see everything about the table
9 mar 2023 · In this video, we'll discuss what composite indexes are, how to create them, and when they can and can't be used. Creating a composite index. Let's start with creating a composite index on our people table. We have been adding single column indexes like this: ALTER TABLE people ADD INDEX first_name (first_name); ALTER TABLE people ADD INDEX ...
MySQL can create composite indexes (that is, indexes on multiple columns). An index may consist of up to 16 columns. For certain data types, you can index a prefix of the column (see Section 8.3.5, “Column Indexes” ).
6 mar 2024 · In MySQL we can create a composite primary key with the PRIMARY KEY clause of the CREATE TABLE statement. We can also use the ADD PRIMARY KEY statement to add a composite primary key to an existing table that doesn’t already have a primary key.
