1
CHAPTER 2
Database Environment
Transparencies
© Pearson Education Limited 1995, 2005
, 2
Chapter 2 - Objectives
• Purpose of three-level database architecture.
• Contents of external, conceptual, and internal levels.
• Purpose of external/conceptual and
conceptual/internal mappings.
• Meaning of logical and physical data independence.
• Distinction between DDL and DML.
• A classification of data models.
© Pearson Education Limited 1995, 2005
, 3
Chapter 2 - Objectives
• Purpose/importance of conceptual modeling.
• Typical functions and services a DBMS should provide.
• Function and importance of system catalog.
• Software components of a DBMS.
• Meaning of client–server architecture and advantages of
this type of architecture for a DBMS.
• Function and uses of Transaction Processing Monitors.
© Pearson Education Limited 1995, 2005
, 4
Objectives of Three-Level Architecture
• All users should be able to access same data.
• A user’s view is immune to changes made in other views.
• Users should not need to know physical database
storage details.
© Pearson Education Limited 1995, 2005
CHAPTER 2
Database Environment
Transparencies
© Pearson Education Limited 1995, 2005
, 2
Chapter 2 - Objectives
• Purpose of three-level database architecture.
• Contents of external, conceptual, and internal levels.
• Purpose of external/conceptual and
conceptual/internal mappings.
• Meaning of logical and physical data independence.
• Distinction between DDL and DML.
• A classification of data models.
© Pearson Education Limited 1995, 2005
, 3
Chapter 2 - Objectives
• Purpose/importance of conceptual modeling.
• Typical functions and services a DBMS should provide.
• Function and importance of system catalog.
• Software components of a DBMS.
• Meaning of client–server architecture and advantages of
this type of architecture for a DBMS.
• Function and uses of Transaction Processing Monitors.
© Pearson Education Limited 1995, 2005
, 4
Objectives of Three-Level Architecture
• All users should be able to access same data.
• A user’s view is immune to changes made in other views.
• Users should not need to know physical database
storage details.
© Pearson Education Limited 1995, 2005
