MariaDB Connector/C Data Structures
This page describes the public data structures used by MariaDB Connector/C.
MYSQL
The MYSQL structure represents one database connection and is used by most of MariaDB Connector/C's API functions. The MYSQL structure needs to be allocated and initialized by the mysql_init() API function. It will be released by the mysql_close() function.
The MYSQL structure should be considered as opaque; copying or changing values of its members might produce unexpected results, errors or program crashes.
MYSQL_RES
The MYSQL_RES structure represents a result set which contains data and metadata information. It will be returned by the mysql_use_result(), mysql_store_result() and mysql_stmt_result_metadata() API functions and needs to be released by mysql_free_result().
The MYSQL_RES structure should be considered as opaque; copying or changing values of its members might produce unexpected results, errors or program crashes.
MYSQL_ROW
MYSQL_ROW represents an array of character pointers, pointing to the columns of the actual data row.
Data will be received by the mysql_fetch_row() function. The size of the array is the number of columns for the current row.
After freeing the result set with mysql_free_result() MYSQL_ROW becomes invalid.
MYSQL_STMT
The MYSQL_STMT structure represents a prepared statement handle and is used by MariaDB Connector/C's prepared statement API functions. The MYSQL_STMT structure needs to be allocated and initialized by the mysql_stmt_init() function and needs to be released by the mysql_stmt_close() function.
The MYSQL_STMT structure should be considered as opaque; copying or changing values of its members might produce unexpected results, errors or program crashes.
MYSQL_FIELD
The MYSQL_FIELD structure describes the metadata of a column. It can be obtained by the mysql_fetch_field() function.
It has the following members:
char * | name | The name of the column |
unsigned int | name_length | The length of column name |
char * | org_name | The original name of the column |
unsigned int | org_name_length | The length of original column name |
char * | table | The name of the table |
unsigned int | table_length | The length of table name |
char * | org_table | The original name of the table |
unsigned int | org_table_length | The length of original table name |
char * | db | The name of the database (schema) |
unsigned int | db_length | The length of database name |
char * | catalog | The catalog name (always 'def') |
unsigned int | catalog_length | The length of catalog name |
char * | def | default value |
unsigned int | def_length | The length of default value |
unsigned int | length | The length (width) of the column definition |
unsigned int | max_length | The maximum length of the column value |
unsigned int | flags | Flags |
unsigned int | decimals | Number of decimals |
enum enum_field_types | type | Field type |
MYSQL_BIND
The MYSQL_BIND structure is used to provide parameters for prepared statements or to receive output column value from prepared statements.
unsigned long * | length | Pointer for the length of the buffer (not used for parameters) |
my_bool * | is_nulll | Pointer which indicates if column is NULL (not used for parameters) |
my_bool * | error | Pointer which indicates if an error occured |
void * | buffer | Data buffer which contains or receives data |
char * | u.indicator | Array of indicator variables for bulk operation parameter |
unsigned long | buffer_length | Length of buffer |
enum enum_field_types | buffer_type | Buffer type |
unsigned long | length_value | Used if length pointer is NULL |
my_bool | error_value | Used if error pointer is NULL |
my_bool | is_null_value | Used if is_null pointer is NULL |
my_bool | is_unsigned | Set if integer type is unsigned |
my_bool | is_null_value | Used if value is NULL |
MYSQL_TIME
The MYSQL_TIME structure is used for date and time values in prepared statements. It has the following members:
unsigned int | year | Year |
unsigned int | month | Month |
unsigned int | day | Day |
unsigned int | hour | Hour |
unsigned int | minute | Minute |
unsigned int | second | Second |
unsigned long | second_part | Fractional seconds (max. 6 digits) |
my_bool | neg | Negative value |
enum enum_mysql_timestamp_type | time_type | Type |
