Class: LMDB::Cursor

Inherits:
Object
  • Object
show all
Defined in:
ext/isomorfeus_hamster_ext/isomorfeus_hamster.c

Overview

A Cursor points to records in a database, and is used to iterate through the records in the database.

Cursors are created in the context of a transaction, and should only be used as long as that transaction is active. In other words, after you Transaction#commit or Transaction#abort a transaction, the cursors created while that transaction was active are no longer usable.

To create a cursor, call Database#cursor and pass it a block for that should be performed using the cursor.

Examples:

Typical usage

env = LMDB.new "databasedir"
db = env.database "databasename"
db.cursor do |cursor|
  rl = cursor.last           #=> content of the last record
  r1 = cursor.first          #=> content of the first record
  r2 = cursor.next           #=> content of the second record
  cursor.put "x", "y", current: true
                             #=> replaces the second record with a new value "y"
end