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MySQL 5.5 Reference Manual  /  ...  /  C API Prepared Statement Type Codes

23.8.9.1 C API Prepared Statement Type Codes

The buffer_type member of MYSQL_BIND structures indicates the data type of the C language variable bound to a statement parameter or result set column. For input, buffer_type indicates the type of the variable containing the value to be sent to the server. For output, it indicates the type of the variable into which a value received from the server should be stored.

The following table shows the permissible values for the buffer_type member of MYSQL_BIND structures for input values sent to the server. The table shows the C variable types that you can use, the corresponding type codes, and the SQL data types for which the supplied value can be used without conversion. Choose the buffer_type value according to the data type of the C language variable that you are binding. For the integer types, you should also set the is_unsigned member to indicate whether the variable is signed or unsigned.

Input Variable C Type buffer_type Value SQL Type of Destination Value
signed char MYSQL_TYPE_TINY TINYINT
short int MYSQL_TYPE_SHORT SMALLINT
int MYSQL_TYPE_LONG INT
long long int MYSQL_TYPE_LONGLONG BIGINT
float MYSQL_TYPE_FLOAT FLOAT
double MYSQL_TYPE_DOUBLE DOUBLE
MYSQL_TIME MYSQL_TYPE_TIME TIME
MYSQL_TIME MYSQL_TYPE_DATE DATE
MYSQL_TIME MYSQL_TYPE_DATETIME DATETIME
MYSQL_TIME MYSQL_TYPE_TIMESTAMP TIMESTAMP
char[] MYSQL_TYPE_STRING TEXT, CHAR, VARCHAR
char[] MYSQL_TYPE_BLOB BLOB, BINARY, VARBINARY
MYSQL_TYPE_NULL NULL

Use MYSQL_TYPE_NULL as indicated in the description for the is_null member in Section 23.8.9, “C API Prepared Statement Data Structures”.

For input string data, use MYSQL_TYPE_STRING or MYSQL_TYPE_BLOB depending on whether the value is a character (nonbinary) or binary string:

  • MYSQL_TYPE_STRING indicates character input string data. The value is assumed to be in the character set indicated by the character_set_client system variable. If the server stores the value into a column with a different character set, it converts the value to that character set.

  • MYSQL_TYPE_BLOB indicates binary input string data. The value is treated as having the binary character set. That is, it is treated as a byte string and no conversion occurs.

The following table shows the permissible values for the buffer_type member of MYSQL_BIND structures for output values received from the server. The table shows the SQL types of received values, the corresponding type codes that such values have in result set metadata, and the recommended C language data types to bind to the MYSQL_BIND structure to receive the SQL values without conversion. Choose the buffer_type value according to the data type of the C language variable that you are binding. For the integer types, you should also set the is_unsigned member to indicate whether the variable is signed or unsigned.

SQL Type of Received Value buffer_type Value Output Variable C Type
TINYINT MYSQL_TYPE_TINY signed char
SMALLINT MYSQL_TYPE_SHORT short int
MEDIUMINT MYSQL_TYPE_INT24 int
INT MYSQL_TYPE_LONG int
BIGINT MYSQL_TYPE_LONGLONG long long int
FLOAT MYSQL_TYPE_FLOAT float
DOUBLE MYSQL_TYPE_DOUBLE double
DECIMAL MYSQL_TYPE_NEWDECIMAL char[]
YEAR MYSQL_TYPE_SHORT short int
TIME MYSQL_TYPE_TIME MYSQL_TIME
DATE MYSQL_TYPE_DATE MYSQL_TIME
DATETIME MYSQL_TYPE_DATETIME MYSQL_TIME
TIMESTAMP MYSQL_TYPE_TIMESTAMP MYSQL_TIME
CHAR, BINARY MYSQL_TYPE_STRING char[]
VARCHAR, VARBINARY MYSQL_TYPE_VAR_STRING char[]
TINYBLOB, TINYTEXT MYSQL_TYPE_TINY_BLOB char[]
BLOB, TEXT MYSQL_TYPE_BLOB char[]
MEDIUMBLOB, MEDIUMTEXT MYSQL_TYPE_MEDIUM_BLOB char[]
LONGBLOB, LONGTEXT MYSQL_TYPE_LONG_BLOB char[]
BIT MYSQL_TYPE_BIT char[]

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