• Define the Database - Specifies data types structures and constraints for the data to be stored
• Construct the Database - Store the data on some storage medium that is controlled by the DBMS
• Manipulate the Database - Querying to retreive specific data, updating to reflect changes in the model of the real world, and generating reports from data

• Store data
• Control or eliminate redundancy
• Provide program-data independence
• Permit multiple views of data
• Support sharing by multiple users
• Support sharing and integration of data between multiple applications
• Control concurrent access to data
• Offer various interfaces for data retreival and manipulation
• Be self-describing/contain its own catalogue for metadata
• Support data abstraction
• Allow complex relationships between objects to be represented
• Enforce integrity constraints on the data
• Restrict unauthorised access
• Facilitate backup and recovery

• DDL - Data Definition Language
• Creating tables, indices
• Manipulating database schema
• DML - Data Manipulation Language
• Queries
• Updating table contents

• Database Administrators
• DDL Statements
• Privileged Commands
• Casual Users
• Interactive Query
• Application Programmers
• Application Programs

• Contains metadata about storeddata and schemas
• Names and sizes of files
• Storage details of files
• Names and data types of data items
• Mappings between schemas
• Constraints
• Statistical information

• Data Definition Compiler
• Processes Schema Definitions
• Stores Schema descriptions in the systems catalogue

• Parses and Validates queries
• Compiles queries to internal form (query plan)
• Passes compiled queries to query optimizer

• Rearranges and reorders operations within query plan
• Eliminates redundancies
• Identifies appropriate algorithms and indexes used to implement operations
• Consults systems catalogue for statistical and other information
• Generates executable code

Compiles DML into executable code that can be sent to the runtime processor.

Consults the System Catalogue

• Executes privileged commands
• Executes query plans from the query optimizer
• Accesses database through stored data manager

• Loading utility is used to load files into DB
• Backup utility dumps DB to secondary storage (tape, typically)
• Recovery utility deals with failure using backup information
• File reorganization utility improves performance
• Performance monitoring provides statistics for DBA to decide whether to reorganize