ch4 acis - 1) What is a database a) Definition i)...

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1) What is a database a) Definition i) Self-describing collection of integrated records b) Purpose i) Keep track of things with more than one theme ii) Spreadsheet (1) List with single theme iii) Database (1) List with multiple theme c) Terms associated with i) Byte (1) Character of data ii) Column (1) Groups up bytes (2) Grouped into rows/records iii) Table/File (1) Group of similar rows/records (2) Every table must have key iv) Database (1) Collection of tables (2) plus relationships among the rows in those tables (3) plus special data (a) called metadata, that describes the structure of database
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(4) Databases are stored on magnetic disks Tables Files + Relationships among rows in tables + Metadata = Database d) Relationships among records i) Key (1) Column/group of columns that identifies a unique row in a table (2) Every table must have key (3) Ex. Student Number ii) Foreign key (1) Term used because such columns are keys, but they are keys of a different (foreign) table than the one in which they reside iii) Relational Database (1) Databases carry their data in the form of tables (2) Represent relationships using foreign keys e) Metadata i) Self Describing (1) Database contains, within itself, a description of its contents
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This note was uploaded on 03/31/2008 for the course ACIS 1504 taught by Professor Jmlacoste during the Spring '07 term at Virginia Tech.

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ch4 acis - 1) What is a database a) Definition i)...

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