Abstract: The relational data model is based on sets of tuples, i.e. it does not allow duplicate tuples an a relation. Many database languages and systems ...
The statements of the extended relational algebra in- clude constructs to query and update a multi-set r e lational database. They are defined below.
Apr 14, 2015 · Relational algebra, as extended by Grefen and de By [32] , works on multisets (or bags) of tuples. A multiset can contain multiple entries of ...
In this paper, relational algebra and relational calculus database query languages (as defined by Klug) are extended to manipulate set-valued attributes and to ...
This paper proposes a complete extended relational algebra with multi-set semantics, having a clear formal background and a close connection to the standard ...
Grefen, P. W. P. J., & de By, R. A. (1993). A Multi-Set Extended Relational Algebra- A Formal Approach to a Practical Issue. (Memoranda informatica; No. 93-31).
Extending relational algebra and relational calculus with set-valued attributes and aggregate functions · An Extended Algebra for Constraint Databases · An ...
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A multi-set extended relational algebra: a formal approach to a practical issue.
This paper proposes a complete extended relational algebra with multi-set semantics, having a clear formal background and a close connection to the standard ...
This paper proposes an extended relational algebra for this purpose, based on the well-known standard relational algebra. The extended algebra provides both ...