Function switch_core_db_exec 

pub unsafe extern "C" fn switch_core_db_exec(
    db: *mut switch_core_db_t,
    sql: *const c_char,
    callback: switch_core_db_callback_func_t,
    data: *mut c_void,
    errmsg: *mut *mut c_char,
) -> c_int

A function to executes one or more statements of SQL.

If one or more of the SQL statements are queries, then the callback function specified by the 3rd parameter is invoked once for each row of the query result. This callback should normally return 0. If the callback returns a non-zero value then the query is aborted, all subsequent SQL statements are skipped and the switch_core_db_exec() function returns the SWITCH_CORE_DB_ABORT.

The 4th parameter is an arbitrary pointer that is passed to the callback function as its first parameter.

The 2nd parameter to the callback function is the number of columns in the query result. The 3rd parameter to the callback is an array of strings holding the values for each column. The 4th parameter to the callback is an array of strings holding the names of each column.

The callback function may be NULL, even for queries. A NULL callback is not an error. It just means that no callback will be invoked.

If an error occurs while parsing or evaluating the SQL (but not while executing the callback) then an appropriate error message is written into memory obtained from malloc() and *errmsg is made to point to that message. The calling function is responsible for freeing the memory that holds the error message. Use switch_core_db_free() for this. If errmsg==NULL, then no error message is ever written.

The return value is is SWITCH_CORE_DB_OK if there are no errors and some other return code if there is an error. The particular return value depends on the type of error.

If the query could not be executed because a database file is locked or busy, then this function returns SWITCH_CORE_DB_BUSY. (This behavior can be modified somewhat using the sswitch_core_db_busy_handler() and switch_core_db_busy_timeout() functions below.)