OceanBase Connector/C |V3.2.4|OceanBase Database| docs|Distributed Database

OceanBase Connector/C

Last Updated：2023-10-24 09:23:04 Updated

OceanBase Connector/C is an OceanBase client development component based on C/C++. OceanBase Connector/C supports the C API library.

OceanBase Connector/C allows C/C++ applications to access OceanBase distributed database clusters from the underlying layer. Then, the applications can perform operations such as database connection, data access, error processing, and prepared statement processing.

OceanBase Connector/C is also called LibobClient and is used as an independent server process for applications to communicate with OBServers based on network connections. A client references the C API header file during compilation and can connect to the C API library file.

Functions and objects

The following table lists the supported C API functions.

For more information about the following functions, see the topic about C API functions of OceanBase Connection/C.

Function	Description
my_init	Initializes the global variables required by OceanBase Database.
mysql_affected_rows	Returns the number of rows modified, deleted, or inserted by the UPDATE, DELETE, or INSERT statement that was last executed.
mysql_autocommit	Sets the autocommit mode.
mysql_change_user	Changes the user and sets the specified database as the default database on the specified connection.
mysql_character_set_name	Returns the name of the default character set for the current connection.
mysql_client_find_plugin	Returns a pointer to a plugin that is loaded.
mysql_client_register_plugin	Adds a plugin structure to the list of plugins that are loaded.
mysql_close	Closes a connection that was previously opened.
mysql_commit	Commits the current transaction.
mysql_connect	Connects to an OBServer.
mysql_create_db	Creates the database that is named by the db parameter.
mysql_data_seek	Searches for an arbitrary row in a query result set.
mysql_debug	Uses a specified string to perform a DEBUG_PUSH operation.
mysql_drop_db	Deletes the database that is named by the db parameter.
mysql_dump_debug_info	Notifies an OBServer to write debugging information to the error log.
mysql_eof	Checks whether the last row of a result set has been read.
mysql_errno	Returns the error code for the most recently invoked API function.
mysql_error	Returns a string ending with a null character and containing the error message for the most recently invoked API function that failed.
mysql_escape_string	Escapes special characters in a string to be used in SQL statements.
mysql_fetch_field	Returns the next field.
mysql_fetch_field_direct	Returns the field with the specified field number.
mysql_fetch_fields	Returns all MYSQL_FIELD structures in a result set as an array. The MYSQL_FIELD structure provides field definitions for columns of the result set.
mysql_fetch_lengths	Returns the lengths of columns in the current row of a result set.
mysql_fetch_row	Obtains the next row of a result set.
mysql_field_count	Returns the number of columns that were most recently queried.
mysql_field_seek	Searches for columns in a row of a result set.
mysql_field_tell	Returns the position of the field cursor used for the last call to the mysql_fetch_field() function.
mysql_free_result	Frees the memory allocated to a result set.
mysql_get_character_set_info	Returns information about the default character set.
mysql_get_client_info	Returns a string that represents the OBClient version.
mysql_get_client_version	Returns the OBClient version as an integer.
mysql_get_host_info	Returns a string that describes the current connection type, including the server host name.
mysql_get_proto_info	Returns the protocol version used for the current connection.
mysql_get_server_info	Returns a string that represents the OBServer version.
mysql_get_server_version	Returns the OBServer version as an integer.
mysql_get_ssl_cipher	Returns the encryption cipher used for a specified connection to the OBServer.
mysql_hex_string	Creates a hexadecimal string that can be used in SQL statements.
mysql_info	Returns a string that provides information about the most recently executed statement.
mysql_init	Assigns or initializes a MySQL object that is suitable for the mysql_real_connect() function.
mysql_insert_id	Returns the value generated for an auto-increment column by the previous INSERT or UPDATE statement.
mysql_kill	Notifies an OBServer to kill the thread specified by pid.
mysql_library_end	Finalizes the C API library.
mysql_library_init	Initializes the C API library.
mysql_list_dbs	Returns a result set that consists of the database names matching the simple regular expression specified by the wild parameter.
mysql_list_fields	Returns a field that matches the simple regular expression specified by the wild parameter.
mysql_list_processes	Returns a result set that describes the current server thread.
mysql_list_tables	Returns a result set that consists of the table names matching the simple regular expression specified by the wild parameter. An H3+ parsing library is added.
mysql_load_plugin	Loads an OBClient plugin with the specified name and type.
mysql_load_plugin_v	Loads an OBClient plugin.
mysql_more_results	Checks whether more results exist.
mysql_next_result	Reads the next statement result to check whether more results exist. You can use this function when you execute multiple statements that are specified as a single statement string, or when you use CALL statements to execute stored procedures. Stored procedures can return multiple result sets.
mysql_num_fields	Returns the number of columns in a specified result set.
mysql_num_rows	Returns the number of rows in a specified result set.
mysql_options	Sets extra connection options and affects the behaviors of a connection.
mysql_options4	Sets extra connection options and affects the behaviors of a connection.
mysql_ping	Checks whether a connection to an OBServer works as expected.
mysql_plugin_options	Passes an option type and value to a plugin.
mysql_query	Executes the SQL statement to which the null termination string stmt_str points.
mysql_real_connect	Establishes a connection to the OBServer where the host is running.
mysql_real_escape_string	Escapes special characters in the string of a statement to generate a hexadecimal string that can be used in SQL statements.
mysql_real_query	Executes the SQL statement to which stmt_str points.
mysql_refresh	Refreshes or resets the tables and caches.
mysql_reload	Notifies an OBServer to reload the privilege tables.
mysql_rollback	Rolls back the current transaction.
mysql_row_seek	Searches for an arbitrary row in a query result set.
mysql_row_tell	Returns the current position of the row cursor for a result set.
mysql_select_db	Sets the database specified by db as the default database (current database) of the specified connection.
mysql_server_end	Finalizes the C API library.
mysql_server_init	Initializes the OBClient library.
mysql_set_character_set	Sets the default character set for the current connection.
mysql_set_local_infile_default	Sets the LOAD DATA LOCAL callback functions to the default values internally used by the C client library.
mysql_set_local_infile_handler	Installs the callbacks to be fired during the execution of LOAD DATA LOCAL statements.
mysql_set_server_option	Enables or disables a connection option.
mysql_shutdown	Shuts down an OBServer.
mysql_sqlstate	Returns a string that ends with a null character and contains the SQLSTATE error code for the most recently executed SQL statement.
mysql_ssl_set	Establishes an encrypted connection by using SSL.
mysql_stat	Returns a string containing server information similar to that provided by the mysqladmin status command. The information includes the uptime in seconds and the number of running threads, questions, reloads, and open tables.
mysql_stmt_affected_rows	Returns the number of rows modified, deleted, or inserted by the UPDATE, DELETE, or INSERT statement that was last executed.
mysql_stmt_attr_get	Obtains the current value for a statement attribute.
mysql_stmt_attr_set	Sets an attribute value for a prepared statement.
mysql_stmt_bind_param	Associates the input data with the parameter markers of a prepared statement.
mysql_stmt_bind_result	Associates output columns in the result set with data buffers and length buffers.
mysql_stmt_close	Closes a prepared statement.
mysql_stmt_data_seek	Searches for an arbitrary row in a statement result set.
mysql_stmt_errno	Returns the error code generated for the most recently revoked statement API function.
mysql_stmt_error	Returns the error message generated for the most recently revoked statement API function.
mysql_stmt_execute	Executes the prepared query associated with a statement handle.
mysql_stmt_fetch	Returns the next row of a result set and returns the values of all associated columns.
mysql_stmt_fetch_column	Returns a column from the current result set row.
mysql_stmt_field_count	Returns the number of columns in the current result set of a prepared statement.
mysql_stmt_free_result	Releases memory associated with the result set generated by executing a prepared statement.
mysql_stmt_init	Creates and returns a MYSQL_STMT handler.
mysql_stmt_insert_id	Returns the value generated for an auto-increment column by a prepared INSERT or UPDATE statement.
mysql_stmt_next_result	Checks whether more results exist for a prepared statement.
mysql_stmt_num_rows	Returns the number of rows in a result set.
mysql_stmt_param_count	Returns the number of parameters in a prepared statement.
mysql_stmt_param_metadata	Returns parameter metadata as a result set.
mysql_stmt_prepare	Prepares the SQL statement to which the stmt_str string points and returns a status value.
mysql_stmt_reset	Resets a statement on an OBServer, the data sent by the mysql_stmt_send_long_data() function, unbuffered result sets, and current errors.
mysql_stmt_result_metadata	Obtains the result set metadata of a prepared statement.
mysql_stmt_row_seek	Searches for an arbitrary row in the result set of a prepared statement.
mysql_stmt_row_tell	Returns the current position of the row cursor for the result set of a prepared statement.
mysql_stmt_send_long_data	Allows an application to send parameter data to an OBServer in pieces or chunks.
mysql_stmt_sqlstate	Returns the SQLSTATE value for the most recently invoked prepared statement API function.
mysql_stmt_store_result	Retrieves and stores a result set.
mysql_store_result	Queries and stores a result set.
mysql_thread_end	Finalizes a thread handle.
mysql_thread_id	Returns the thread ID for the current connection.
mysql_thread_init	Initializes a thread handle.
mysql_thread_safe	Indicates whether the OBClient library is compiled as thread-safe.
mysql_use_result	Retrieves a result set row by row.
mysql_warning_count	Returns the number of errors, warnings, and notes generated by the execution of the previous SQL statement.

C API data structures

Object	Description
MYSQL	The handler for a database connection.
MYSQL_RES	The result of a query.
MYSQL_ROW	The representation of a data row.
MYSQL_FIELD	The metadata of a column.
MYSQL_FIELD_OFFSET	The representation of an offset into a column list.
my_ulonglong	A basic type.
my_bool	A basic type.

More information

For more information about OceanBase Connector/C, see OceanBase Connector/C.