COMM 205 Lecture Notes - Lecture 5: Rade People, Order Of Merit, Horse Length
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Example of fields and records (cid:190) describe the fundamental concepts of the (cid:190) describe the fundamental concepts of the relational database. relational database. Data hierarchy (cid:190) compose of tables (rows and columns) (cid:190) compose of tables (rows and columns) File (table) a logical grouping of related records. Bit represents a single character. (binary digit) represents the smallest unit of data a computer can process. Relational databases: table (cid:131) data organized as two-dimensional tables. (cid:131) table (file) (cid:131) row (record) (cid:131) column (field or attribute) (cid:131) primary key : field(s) whose value uniquely identifies each row. 38. 00 (cid:131) atomic primary key (cid:131) atomic primary key: a primary key that consist of only one field, a primary key that consist of only one field. Representing data in tables (cid:190) a primary key that consist of more than one field. (cid:190) a primary key that consist of more than one field. (cid:190) a database usually has more than one table.
