oracle aide

September 24, 2007

Passed 1z0-042 – OCA exam

Filed under: 1z0-042, oca — oracleaide @ 2:19 pm

Thanks to:

  • The Book: Oracle Database 10g OCP Certification All-In-One Exam Guide
  • The Practice Test software from SelfTest
  • (more…)

    August 31, 2007

    Oracle locks cheat sheet

    Filed under: 1z0-042, locks, oca — oracleaide @ 6:13 pm
    SQL Statement Row
    locks?
    Mode
    of
    table lock
    Lock Modes Permitted?
    RS RX S SRX X
    SELECT…FROM table…
    INSERT INTO table RX
    UPDATE table … RX
    DELETE FROM table … RX
    SELECT … FROM table FOR UPDATE OF … RS
    LOCK TABLE table IN ROW SHARE MODE RS
    LOCK TABLE table IN ROW EXCLUSIVE MODE RX
    LOCK TABLE table IN SHARE MODE S
    LOCK TABLE table IN
    SHARE ROW EXCLUSIVE MODE
    SRX
    LOCK TABLE table IN EXCLUSIVE MODE X

  • RS: row share
  • RX: row exclusive
  • S: share
  • SRX: share row exclusive
  • X: exclusive
  •  a lock.

  •  A lock, if no conflicting row locks
    are held by another transaction.
    Otherwise, waits occur.

  • The source.

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