Download presentation
Presentation is loading. Please wait.
Published byEllen Jones Modified over 9 years ago
1
Howard Paul
2
Sequential Access
3
Index Files and Data File Random Access
4
Relational Tables Random Access
6
A student has ID, last name, first name, address, email, major field, … A course has ID, title, credits, prereq,… A student may take multiple courses in one term and grades are assigned. A student may take courses in multiple terms. A course may be offered in multiple terms. A term may have multiple courses offered.
7
A faculty has ID, last name, first name, address, email, department, college, … A faculty may teach multiple courses in one semester. An offered course has ID, course number, year, term, faculty, classroom, and many students
8
Entity (Phy. Object, Relation, Table) Attribute (Property, Column) Relationship (Abs. Object, Relation) Record (Row)
14
The database has one or more tables A table has columns and rows Each cell may store at most one value Each table must have a Primary Key (PK) The PK represents a unique row of data A PK value and a column determines just a value A PK may consist one or more columns A table may contain PK columns of other tables, called Foreign Key (FK)
19
http://cis.csuohio.edu/~paul/331.html
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.