udm_alloc_agent() returns mnogosearch agent identifier on success, FALSE on error. This function creates a session with database parameters.
dbaddr - URL-style database description. Options (type, host, database name, port, user and password) to connect to SQL database. Do not matter for built-in text files support. Format: DBAddr DBType:[//[DBUser[:DBPass]@]DBHost[:DBPort]]/DBName/ Currently supported DBType values are: mysql, pgsql, msql, solid, mssql, oracle, ibase. Actually, it does not matter for native libraries support. But ODBC users should specify one of supported values. If your database type is not supported, you may use "unknown" instead.
dbmode - You may select SQL database mode of words storage. When "single" is specified, all words are stored in the same table. If "multi" is selected, words will be located in different tables depending of their lengths. "multi" mode is usually faster but requires more tables in database. If "crc" mode is selected, mnoGoSearch will store 32 bit integer word IDs calculated by CRC32 algorythm instead of words. This mode requres less disk space and it is faster comparing with "single" and "multi" modes. "crc-multi" uses the same storage structure with the "crc" mode, but also stores words in different tables depending on words lengths like "multi" mode. Format: DBMode single/multi/crc/crc-multi
Note: dbaddr and dbmode must match those used during indexing.
Note: In fact this function does not open connection to database and thus does not check entered login and password. Actual connection to database and login/password verification is done by udm_find().