Chapter 3
Database Management Systems (DBMS)
A database management system helps you specify the logical organization for a database and access and use that info within the database.
RDBMS
Collection of Information: You need to be able to collect specific information for your database Logical Structure - the data daictionary contains the logical structure for the information. You create the data dictionary which basically sets up how the data needs to be seen logically Logical TIes: The information needs to be tied logically with foreign and primary keys. Needs to have integrity contstraints that will help keep the info AOK
Data Warehouse
Data warehouses is the logical collection of information gathered from many different operational databases and are used to create business intelligence that helps support decision making.
Foreign Key
a primary key of one file that appears in another file.
DBMS Engine
accepts logical requests from the various other DBMS subsystems and converts them into their physical equivalent and actually accesses the database and data dictionary as they exist on a storage device.
Application generation subsystem
facilities to help you develop transaction intensive applications.
Data manipulation Subsystem
helps you add change and delete information in a database and query it for valuable information (tools like query within Microsoft Access)
Data Definition Subsytem
helps you create and maintain the data dictionary and define the structure of the files in a database. This is the logical structure of how the info flows (think customer --> Order-->product)
Data administration subsystem
helps you manage the overall database environment by providing facilities for backup and recovery, security management, query optimization, concurrency control and change management
Primary Key
is a field that uniquely describes each record. When something is established as a primary key you cannot leave it blank.
Integrity constraints
rules that help ensure the quality of the information.
