Database Systems (TODS)


Search Issue
enter search term and/or author name


ACM Transactions on Database Systems (TODS), Volume 2 Issue 3, Sept. 1977

Optimal policy for batch operations: backup, checkpointing, reorganization, and updating
Guy M. Lohman, John A. Muckstadt
Pages: 209-222
DOI: 10.1145/320557.320558
Many database maintenance operations are performed periodically in batches, even in realtime systems. The purpose of this paper is to present a general model for determining the optimal frequency of these batch operations. Specifically, optimal...

Interval hierarchies and their application to predicate files
Kai C. Wong, Murray Edelberg
Pages: 223-232
DOI: 10.1145/320557.320562
Predicates are used extensively in modern database systems for purposes ranging from user specification of associative accesses to data, to user-invisible system control functions such as concurrency control and data distribution. Collections of...

Effects of locking granularity in a database management system
Daniel R. Ries, Michael Stonebraker
Pages: 233-246
DOI: 10.1145/320557.320566
Many database systems guarantee some form of integrity control upon multiple concurrent updates by some form of locking. Some “granule” of the database is chosen as the unit which is individually locked, and a lock management...

Some high level language constructs for data of type relation
Joachim W. Schmidt
Pages: 247-261
DOI: 10.1145/320557.320568
For the extension of high level languages by data types of mode relation, three language constructs are proposed and discussed: a repetition statement controlled by relations, predicates as a generalization of Boolean expressions, and a...

Multivalued dependencies and a new normal form for relational databases
Ronald Fagin
Pages: 262-278
DOI: 10.1145/320557.320571
A new type of dependency, which includes the well-known functional dependencies as a special case, is defined for relational databases. By using this concept, a new (“fourth”) normal form for relation schemata is defined. This fourth...

The determination of efficient record segmentations and blocking factors for shared data files
Salvatore T. March, Dennis G. Serverance
Pages: 279-296
DOI: 10.1145/320557.320574
It is generally believed that 80 percent of all retrieval from a commercial database is directed at only 20 percent of the stored data items. By partitioning data items into primary and secondary record segments, storing them in physically...