AUTO_INCREMENT
attribute can be used to generate a unique identity for new rows: Office 2010 32 bit product key generator.AUTO_INCREMENT
column, so MySQL assigned sequence numbers automatically. You can also explicitly assign 0 to the column to generate sequence numbers, unless the NO_AUTO_VALUE_ON_ZERO
SQL mode is enabled. For example: NOT NULL
, it is also possible to assign NULL
to the column to generate sequence numbers. For example: AUTO_INCREMENT
column, the column is set to that value and the sequence is reset so that the next automatically generated value follows sequentially from the largest column value. For example: AUTO_INCREMENT
column value in an InnoDB
table does not reset the AUTO_INCREMENT
sequence as it does for MyISAM
and NDB
tables. AUTO_INCREMENT
value with the LAST_INSERT_ID()
SQL function or the mysql_insert_id()
C API function. These functions are connection-specific, so their return values are not affected by another connection which is also performing inserts. AUTO_INCREMENT
column that is large enough to hold the maximum sequence value you will need. When the column reaches the upper limit of the data type, the next attempt to generate a sequence number fails. Use the UNSIGNED
attribute if possible to allow a greater range. For example, if you use TINYINT
, the maximum permissible sequence number is 127. For TINYINT UNSIGNED
, the maximum is 255. See Integer Types (Exact Value) - INTEGER, INT, SMALLINT, TINYINT, MEDIUMINT, BIGINT for the ranges of all the integer types.LAST_INSERT_ID()
and mysql_insert_id()
actually return the AUTO_INCREMENT
key from the first of the inserted rows. This enables multiple-row inserts to be reproduced correctly on other servers in a replication setup.AUTO_INCREMENT
value other than 1, set that value with CREATE TABLE
or ALTER TABLE
, like this: AUTO_INCREMENT
usage specific to InnoDB
, see AUTO_INCREMENT Handling in InnoDB.MyISAM
tables, you can specify AUTO_INCREMENT
on a secondary column in a multiple-column index. In this case, the generated value for the AUTO_INCREMENT
column is calculated as MAX(auto_increment_column
) + 1 WHERE prefix=given-prefix
. This is useful when you want to put data into ordered groups. AUTO_INCREMENT
column is part of a multiple-column index), AUTO_INCREMENT
values are reused if you delete the row with the biggest AUTO_INCREMENT
value in any group. This happens even for MyISAM
tables, for which AUTO_INCREMENT
values normally are not reused. AUTO_INCREMENT
column is part of multiple indexes, MySQL generates sequence values using the index that begins with the AUTO_INCREMENT
column, if there is one. For example, if the animals
table contained indexes PRIMARY KEY (grp, id)
and INDEX (id)
, MySQL would ignore the PRIMARY KEY
for generating sequence values. As a result, the table would contain a single sequence, not a sequence per grp
value.AUTO_INCREMENT
is available here:AUTO_INCREMENT
attribute to a column: CREATE TABLE Statement, and ALTER TABLE Statement. AUTO_INCREMENT
behaves depending on the NO_AUTO_VALUE_ON_ZERO
SQL mode: Server SQL Modes. LAST_INSERT_ID()
function to find the row that contains the most recent AUTO_INCREMENT
value: Information Functions. AUTO_INCREMENT
value to be used: Server System Variables. AUTO_INCREMENT
and replication: Replication and AUTO_INCREMENT. AUTO_INCREMENT
(auto_increment_increment
and auto_increment_offset
) that can be used for replication: Server System Variables. Halo 2 vista activation key generator.AUTO_INCREMENT
attribute can be used to generate a unique identity for new rows: AUTO_INCREMENT
column, so MySQL assigned sequence numbers automatically. You can also explicitly assign 0 to the column to generate sequence numbers, unless the NO_AUTO_VALUE_ON_ZERO
SQL mode is enabled. For example: NOT NULL
, it is also possible to assign NULL
to the column to generate sequence numbers. For example: AUTO_INCREMENT
column, the column is set to that value and the sequence is reset so that the next automatically generated value follows sequentially from the largest column value. For example: AUTO_INCREMENT
column value in an InnoDB
table does not reset the AUTO_INCREMENT
sequence as it does for MyISAM
and NDB
tables. AUTO_INCREMENT
value with the LAST_INSERT_ID()
SQL function or the mysql_insert_id()
C API function. These functions are connection-specific, so their return values are not affected by another connection which is also performing inserts. AUTO_INCREMENT
column that is large enough to hold the maximum sequence value you will need. When the column reaches the upper limit of the data type, the next attempt to generate a sequence number fails. Use the UNSIGNED
attribute if possible to allow a greater range. For example, if you use TINYINT
, the maximum permissible sequence number is 127. For TINYINT UNSIGNED
, the maximum is 255. See Integer Types (Exact Value) - INTEGER, INT, SMALLINT, TINYINT, MEDIUMINT, BIGINT for the ranges of all the integer types.LAST_INSERT_ID()
and mysql_insert_id()
actually return the AUTO_INCREMENT
key from the first of the inserted rows. This enables multiple-row inserts to be reproduced correctly on other servers in a replication setup.AUTO_INCREMENT
value other than 1, set that value with CREATE TABLE
or ALTER TABLE
, like this: AUTO_INCREMENT
usage specific to InnoDB
, see AUTO_INCREMENT Handling in InnoDB.MyISAM
tables, you can specify AUTO_INCREMENT
on a secondary column in a multiple-column index. In this case, the generated value for the AUTO_INCREMENT
column is calculated as MAX(auto_increment_column
) + 1 WHERE prefix=given-prefix
. This is useful when you want to put data into ordered groups. AUTO_INCREMENT
column is part of a multiple-column index), AUTO_INCREMENT
values are reused if you delete the row with the biggest AUTO_INCREMENT
value in any group. This happens even for MyISAM
tables, for which AUTO_INCREMENT
values normally are not reused. AUTO_INCREMENT
column is part of multiple indexes, MySQL generates sequence values using the index that begins with the AUTO_INCREMENT
column, if there is one. For example, if the animals
table contained indexes PRIMARY KEY (grp, id)
and INDEX (id)
, MySQL would ignore the PRIMARY KEY
for generating sequence values. As a result, the table would contain a single sequence, not a sequence per grp
value.AUTO_INCREMENT
is available here:AUTO_INCREMENT
attribute to a column: CREATE TABLE Statement, and ALTER TABLE Statement. AUTO_INCREMENT
behaves depending on the NO_AUTO_VALUE_ON_ZERO
SQL mode: Server SQL Modes. LAST_INSERT_ID()
function to find the row that contains the most recent AUTO_INCREMENT
value: Information Functions. AUTO_INCREMENT
value to be used: Server System Variables. AUTO_INCREMENT
and replication: Replication and AUTO_INCREMENT. AUTO_INCREMENT
(auto_increment_increment
and auto_increment_offset
) that can be used for replication: Server System Variables.