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Oracle Tutorials - What Is a Data Lock

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(Continued from previous topic...)

What Is a Data Lock?

A data lock is logical flag the Oracle server is placed on data objects to give an exclusive right to a transaction. Statements in other transactions needs to respect data locks based on certain rules. Rules on data locks are:

  • SELECT query statements do not create any data locks.
  • INSERT, UPDATE, and DELETE statements create data locks on the affected rows.
  • Data locks are released when the owner transaction ends.

(Continued on next topic...)

  1. What Is a Transaction?
  2. How To Start a New Transaction?
  3. How To End the Current Transaction?
  4. How To Create a Test Table for Transaction Testing?
  5. How To Commit the Current Transaction?
  6. How To Rollback the Current Transaction?
  7. What Happens to the Current Transaction If a DDL Statement Is Executed?
  8. What Happens to the Current Transaction If the Session Is Ended?
  9. What Happens to the Current Transaction If the Session Is Killed?
  10. How Does Oracle Handle Read Consistency?
  11. What Is a READ WRITE Transaction?
  12. What Is a READ ONLY Transaction?
  13. How To Set a Transaction To Be READ ONLY?
  14. What Are the Restrictions in a READ ONLY Transaction?
  15. What Are the General Rules on Data Consistency?
  16. What Are Transaction Isolation Levels Supported by Oracle?
  17. What Is a Data Lock?
  18. How Data Locks Are Respected?
  19. How To Experiment a Data Lock?
  20. How To View Existing Locks on the Database?
  21. What Is a Dead Lock?
  22. How Oracle Handles Dead Locks?

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