Uses a two dimensional table of rows and columns of data o Rows are records o

Uses a two dimensional table of rows and columns of

This preview shows page 13 - 16 out of 23 pages.

Uses a two-dimensional table of rows and columns of data o Rows are records o Columns are fields Data dictionary : Stores definitions o Data types for fields, default values, and validation rules for data in each field Primary key o Uniquely identifies every record in a relational database Foreign key o Field in a relational table that matches the primary key column of another table o Used to cross-reference tables Normalization o Improves database efficiency by eliminating redundant data Ensures that only related data is stored in a table o Goes through different stages from first normal form (1NF) to fifth normal form (5NF) Retrieves data from tables using operations that pick and combine data from one or more tables o Select o Project o Join o Intersection o Union o Difference Components of a DBMS Database engine Data definition Data manipulation Application generation Data administration Database Engine
Image of page 13
Heart of DBMS software Responsible for data storage, manipulation, and retrieval Converts logical requests from users into their physical equivalents o By interacting with other components of the DBMS Data Definition Creates and maintains the data dictionary Defines the structure of files in a database Makes changes to a database’s structure o Adding and deleting fields o Changing field size and data type Data Manipulation Used to add, delete, modify, and retrieve records from a database Uses a query language o Structured Query Language (SQL) Standard fourth-generation query language that consists of several keywords specifying actions to take o Query by example (QBE) Involves requesting data from a database by constructing a statement formed by query forms Application Generation Designs elements of an application using a database o Data entry screens o Interactive menus o Interfaces with other programming languages Used by IT professionals and database administrators Data Administration Used for the tasks backup and recovery, security, and change management Used to determine who has permission to perform certain functions o Summarized as create, read, update, and delete (CRUD) Database administrator (DBA) o Handles database design and management Setting up database Establishing security measures to determine users’ access rights Developing recovery procedures when data is lost or corrupted
Image of page 14
Evaluating database performance Adding and fine-tuning database functions Recent Trends in Database Design and Use Data-driven website o Interface to a database o Retrieves data and allows users to enter data o Improves access to information o Gives users more current information from a variety of data sources Distributed database : Stores data on multiple servers throughout an organization Approaches to setting up a DDBMS o Fragmentatio n: Addresses how tables are divided among multiple locations o Replication : Each site stores a copy of the data in the organization’s database o Allocation : Combines fragmentation and replication, with each site
Image of page 15
Image of page 16

You've reached the end of your free preview.

Want to read all 23 pages?

  • Fall '16
  • Database management system, Data Warehouses

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture