by admin | Jun 17, 2015 | sem3
Functional Dependency Functional dependency (FD) is a combinations of constraints between 2 attributes in a relation. Functional dependency explians that if two records have same values for attributes A1, A2,…, An, then those two records must have to have same...
by admin | Jun 17, 2015 | sem3
Domain key normal form After a SQL database is in third normal form, you’ve eliminated most, but not all, chances of modification anomalies. Normal forms beyond the third are defined to squash those few remaining bugs. Domain key normal form (DK/NF) Boyce-Codd normal...
by admin | Jun 17, 2015 | sem3
Denormalization In a relational database, denormalization is an approach to optimizing performance in which the administrator selectively adds back specific instances of duplicate data after the data structure has been normalized. In a relational database,...
by admin | Jun 17, 2015 | sem3
Database normalization forms Normalization If a database design is not perfect, it may contain anomalies, which are like a bad dream for any database administrator. Managing a database with anomalies is next to impossible. Update anomalies − If data items are...
by admin | Jun 16, 2015 | sem3
Codds Rules Dr Edgar F. Codd, once his intensive analysis on the relational Model of information systems, came up with twelve rules of his own, that consistent with him, a database should adjust so as to be considered a real relational database. These rules may be...
by admin | Jun 16, 2015 | sem3
ER Model to Relational Model In ER Model, when conceptualized into diagrams, gives a easy overview of entity-relationship, which is Simpler to understand. ER diagrams can be mapped to relational schema, that is, it is possible to create relational schema using ER...
