COMPSCI 1BA3 Lecture Notes - Sans-Serif, Foreign Key, Subliminal Stimuli
4 Feb 2014
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Access: power point 1 relational database management systems (rdbms: query = ask dbase a question = english rdbms syntax; form (input), Report (output: navigation pane database objects; datasheet view direct entry of fields and records, organizing data- the first step is to identify each entity, and its individual attributes. Entity: a person, object or event- attributes as a set of fields, each entity is a table. Each field (i. e. , column) has a specific data-type. A set of field values is called a record (i. e. , row) Pk must have unique values; no duplicates allowed. Pk must not have a null value; a data value is required. For each non-null fk value, a corresponding pk value must exist elsewhere (i. e. , in another table in the database) Fk values may be duplicated, but satellite data are different for each occurrence; fk can have null value in some instances.
