It must defined as a key (not necessarily the PRIMARY KEY or UNIQUE key). The automatically generated value can never be lower than 0.Įach table can have only one AUTO_INCREMENT column. This also applies to 0, unless the NO_AUTO_VALUE_ON_ZERO SQL_MODE is enabled.ĪUTO_INCREMENT columns start from 1 by default. When you insert a new record to the table (or upon adding an AUTO_INCREMENT attribute with the ALTER TABLE statement), and the auto_increment field is NULL or DEFAULT (in the case of an INSERT), the value will automatically be incremented. The AUTO_INCREMENT attribute can be used to generate a unique identity for new rows. Generating Auto_Increment Values When Adding the Attribute.CHECK Constraints, DEFAULT Values and Virtual Columns.Setting or Changing the Auto_Increment Value.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |