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Howard Paul. Sequential Access Index Files and Data File Random Access.

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Presentation on theme: "Howard Paul. Sequential Access Index Files and Data File Random Access."— Presentation transcript:

1 Howard Paul

2 Sequential Access

3 Index Files and Data File Random Access

4 Relational Tables Random Access

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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)

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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)

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19 http://cis.csuohio.edu/~paul/331.html


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