Berkeley DB Reference Guide: Access Methods
Retrieving records
The DB->get function is the standard function for retrieving records from the database. In general, the get function takes a key and returns the associated data from the database.
There are a few flags that you can set to customize retrieval:
- DB_GET_BOTH
- Search for a matching key and data item, i.e., only return if both the key and the data items match those stored in the database.
- DB_RMW
- Acquire write locks instead of read locks during retrieval. This can enhance performance in threaded applications where deadlock is a concern.
- DB_SET_RECNO
- If the underlying database is a Btree, and was configured so that it is possible to search it by logical record number, retrieve a specific record.
If the database has been configured to support duplicate records, DB->get will always return the first data item in the duplicate set.
