Memory and Database

Tuesday, November 07, 2006

Database Terminology

Describing the collection of files as related means that it has a common purpose (e.g., data about students). Sometimes files are also called tables, and there are synonyms for some other terms. A table is the formal name given to the group of records that contain the elements of the collection. A table normally represents a distinct object (business clients or library books), or an event (product orders or stock prices). A table is a basic unit for storing data in the relational database. Files contain records (or rows). The fields in a record provide a complete description of each item in a collection. A record is a unique instance of data about an object or event. Each record contains an instance of a file. For example, if the file stores data about a student, each record will contain data about a single student.

Records have fields (or columns). A field is the most basic structural unit of a database. It is a container for a piece of data. In most cases, only a single logical piece of data fits in each field. Fields store the details of an instance (e.g., student's first name, last name, or date of birth). A byte, a unit of storage sufficient to store a single character, consists of a string of eight contiguous bits or binary digits.

Others relate a table to a spreadsheet; for example, a spreadsheet that contains data about books. A collection of related tables is a relational database.

DBMS (Database Management System)
Database handling techniques grew out of earlier and simpler file processing techniques. A file consists of an ordered collection of records; a database consists of two or more related files that we might want to process together in various different ways. It will store not only the individual records containing the numbers or words needed for some application, but auxiliary information which will allow those records to be accessed more quickly, or which will link related records or data items together. A database designer may be required to choose how much and what sort of auxiliary information to store, using his knowledge of how the database will be used.

Handling large volumes of data manually is a nightmare for a database administrator. In the database arena, a type of software that hastens database administration and management is a DataBase Management System (DBMS) software. DBMS is a data storage and retrieval system which permits data to be stored dnon-redundantly while making it appear to the user as if data is well-integrated.

Database Concepts. WENT1999
Mysql & mSql O’Reilly


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