{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

CSC 4402 20090831

CSC 4402 20090831 - Relational data manipulation is...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
CSC 4402 8/31/2009 Page 1 of 1 Data models A data model is a collection of tools for describing: Data Data relationships Data semantics Data constraints The 3 major components of any data model are: Data structures Data manipulation Data integrity An object-oriented/object-relational database starts with a relational database, but is expanded to support operations that maintain the relationship between objects and data. Relational data model The relational data model is based on a data structure of tables.
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Relational data manipulation is performed by relational algebra or relational calculus. There are two integrity rules: 1. Entity integrity – you cannot have invalid values in an entity 2. Referential integrity – When referencing values from one table to another, the referenced value is guaranteed to exist. Database languages Structured Query Language (SQL) is a declarative DML. SQL contains a DDL and DML. Database design...
View Full Document

{[ snackBarMessage ]}

Ask a homework question - tutors are online