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SQL for Dummies
7th Edition Notes
Question | Answer |
---|---|
Database: | A self-describing collection of integrated records |
Record: | A representation of some physical or conceptual object |
Metadata: | The data the describes the data's structure within a database; structural data |
Integrated Data: | Data that includes not only data items but also the relationships among data items |
Data Dictionary: | Metadata stored in an area of data which describes the tables, columns, indexes, constraints, and other items that make up a database |
DBMS: | Database management system |
DBMS description: | A set of programs used to define, administer, and process databases and their associated applications. |
SAN: | Storage Area Network - storing daa on the Internet |
Flat Files: | Data files with minimum structure; a collection of data records, one after another, in a specified format |
The three database models: | Hierarchical, Network, and Relational |
Hierarchical Database: | These databases arrange their data in a simple hierarchical structure that allows fast access.They suffer from redundancy problems and their structural inflexibility makes database modification difficult. |
Network Database: | Network databases have minimal redundancy but have structural complexity |
Relational Database: | These databases store their data in tables that are related to each other. |
Enterprise Databases: | Databases built according to the hierarchical or network model. |
SQL applies only to which database model? | Relational databases / Object-relational databases |
Relation: | A 2D array of rows and columns, containing single-valued entries and no duplicate rows. Each cell in an array can have only one value and no two rows may be identical |
View: | A subset of a database that an application can process AKA virtual tables |