A nonrestrictive concurrency control protocol for object-oriented databases

D. Agrawal, A. El Abbadi

Research output: Contribution to journalArticle

6 Citations (Scopus)


We propose an algorithm for executing transactions in object-oriented databases. The object-oriented database model generalizes the classical model of database concurrency control by permitting accesses to class and instance objects, by permitting arbitrary operations on objects as opposed to traditional read and write operations, and by allowing nested execution of transactions on objects. In this paper, we first develop a uniform methodology for treating both classes and instances. We then develop a two-phase locking protocol with a new relationship between locks called ordered sharing for an object-oriented database. Ordered sharing does not restrict the execution of conflicting operations. Finally, we extend the protocol to handle objects that execute methods on other objects thus resulting in the nested execution of transactions. The resulting protocol permits more concurrency than other known locking-based protocols.

Original languageEnglish
Pages (from-to)7-31
Number of pages25
JournalDistributed and Parallel Databases
Issue number1
Publication statusPublished - 1 Jan 1994



  • locking protocols
  • nested transactions
  • schema evolution
  • serializability
  • typed objects

ASJC Scopus subject areas

  • Software
  • Information Systems
  • Hardware and Architecture
  • Information Systems and Management

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