Spec-Zone .ru
спецификации, руководства, описания, API
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Spec-Zone .ru
спецификации, руководства, описания, API
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my_ulonglong mysql_insert_id(MYSQL *mysql)
Returns the value generated for an AUTO_INCREMENT column by the previous INSERT
or UPDATE statement. Use this function after you have performed an INSERT statement into a table that contains an AUTO_INCREMENT
field, or have used INSERT or UPDATE to set a column value with LAST_INSERT_ID(. expr)
The return value of mysql_insert_id()
is always zero unless explicitly updated under one of the following conditions:
INSERT statements that store a value into an AUTO_INCREMENT
column. This is true whether the value is automatically generated by storing the special values NULL or 0 into the column, or is an explicit
nonspecial value.
In the case of a multiple-row INSERT statement, mysql_insert_id() returns the first automatically generated AUTO_INCREMENT value that was successfully inserted.
If no rows are successfully inserted, mysql_insert_id()
returns 0.
If an INSERT
... SELECT statement is executed, and no automatically generated value is successfully
inserted, mysql_insert_id()
returns the ID of the last inserted row.
If an INSERT
... SELECT statement uses LAST_INSERT_ID(, expr)mysql_insert_id() returns expr.
INSERT statements that generate an AUTO_INCREMENT value by inserting LAST_INSERT_ID( into any
column or by updating any column to expr)LAST_INSERT_ID(. expr)
If the previous statement returned an error, the value of mysql_insert_id() is undefined.
The return value of mysql_insert_id()
can be simplified to the following sequence:
If there is an AUTO_INCREMENT column, and an
automatically generated value was successfully inserted, return the first such value.
If LAST_INSERT_ID( occurred
in the statement, return expr)expr, even if there was an AUTO_INCREMENT column in the affected table.
The return value varies depending on the statement used. When called after an INSERT
statement:
If there is an AUTO_INCREMENT column in
the table, and there were some explicit values for this column that were successfully
inserted into the table, return the last of the explicit values.
When called after an INSERT ... ON DUPLICATE KEY UPDATE statement:
If there is an AUTO_INCREMENT column in
the table and there were some explicit successfully inserted values or some updated values,
return the last of the inserted or updated values.
mysql_insert_id() returns 0 if the previous
statement does not use an AUTO_INCREMENT value. If you need to save the value for
later, be sure to call mysql_insert_id() immediately after the statement that generates the value.
The value of mysql_insert_id() is
affected only by statements issued within the current client connection. It is not affected by statements issued
by other clients.
The LAST_INSERT_ID()
SQL function will contain the value of the first automatically generated value that was successfully inserted.
LAST_INSERT_ID()
is not reset between statements because the value of that function is maintained in the server. Another
difference from mysql_insert_id() is
that LAST_INSERT_ID()
is not updated if you set an AUTO_INCREMENT column to a specific nonspecial value.
See Section
12.14, "Information Functions".
mysql_insert_id() returns 0 following a CALL
statement for a stored procedure that generates an AUTO_INCREMENT value because in
this case mysql_insert_id() applies to CALL and not the statement within the procedure. Within the procedure, you
can use LAST_INSERT_ID() at the SQL level to obtain the AUTO_INCREMENT
value.
The reason for the differences between LAST_INSERT_ID() and mysql_insert_id() is that LAST_INSERT_ID() is made easy to use in scripts while mysql_insert_id() tries to provide more exact information about what happens to
the AUTO_INCREMENT column.
Described in the preceding discussion.
None.