1. Database Management Systems
Introduction

2. In the Beginning…
Customer
Program 1

3. Program-Data Dependence
DATA DIVISION.
FILE SECTION.
FD EMP-FILE
LABEL RECORDS ARE OMITTED.
01 EMP-RECORD.
05 EMP-NUMBER PIC 9(4).
05 EMP-LASTNAME PIC X(11).
05 EMP-FIRSTNAME PIC X(11).
05 EMP-SEX PIC X(1).
05 EMP-DEPTID PIC X(4).
05 EMP-SALARY PIC 9(8).

4. File System Model Cust Program 1 Program 2 Sales Program 3 Program 4
Inv
Program 5

5. Problems with File System Model
Changes to file structure or file location effect many programs causing high maintenance costs.
Data in various and sometimes proprietary data formats.
File Indexes were easily corrupted if not open during data entry, updates, or deletes.
All Data validation was completely dependent on all application programs.
All Data security was completely dependent on all application programs.
Efficient Multi-application / multi-user access to the same file(s) required strict adherence to agreed upon locking strategies.
Integrated backup and recovery of hundreds of data files is difficult to control.
Tendency for redundant data to enter various data files.

6. The Solution: DBMS File 1 Program 1 DBMS Program 2 Cust SQL Program 3
Sales
Inv
Program 4
File X
Program 5
Changes to file structure or file location are transparent to application programs. Maintenance costs drop dramatically.

7. The Solution: DBMS Q & R tools File 1 Program 1 DBMS Program 2 Cust
SQL
Program 3
Sales
Inv
Program 4
File X
Program 5
All data is available through a standard SQL interface and related, industry standard query and reporting tools.

8. The Solution: DBMS File 1 Program 1 DBMS Program 2 Index Index Cust
SQL
Program 3
Index
Sales
Inv
Program 4
Index
File X
Program 5
All Indexes are automatically opened and updated during insert, update, and delete operations eliminating the primary cause of index corruption.

9. The Solution: DBMS File 1 Program 1 DBMS Program 2 Constraints Cust
SQL
Program 3
Sales
Inv
Program 4
File X
Program 5
All Data validation rules are defined within the DBMS and enforced independently of application program logic.

10. The Solution: DBMS File 1 Program 1 DBMS Program 2 Users Cust SQL
Sales
Grants
Inv
Program 4
File X
Program 5
Primary responsibility for Data security is now handled by the DBMS providing user based security down to the attribute level.

11. The Solution: DBMS File 1 Program 1 DBMS Program 2 Cust SQL Program 3
Sales
Locks
Rollbacks
Commits
Transactions
Inv
Program 4
File X
Program 5
All aspects of multi-user access are handled by the DBMS.

12. The Solution: DBMS Recovery Backup File 1 Program 1 DBMS Program 2
Cust
Log
Files
SQL
Program 3
Sales
Inv
Program 4
File X
Program 5
A comprehensive, integrated solution to backup and recovery is provided.

13. The Solution: DBMS DBA Schema File 1 Program 1 DBMS Program 2 Cust SQL
Sales
Inv
Program 4
File X
Program 5
A single normalized conceptual model of all data managed by a database administrator (DBA) eliminating redundant and therefore inconsistent data.

14. Summary of DBMS Solutions
Changes to file structure or file location are transparent to application programs. Maintenance costs drop dramatically.
All data is available through a standard SQL interface and related, industry standard query and reporting tools.
All Indexes are automatically opened and updated during insert, update, and delete operations eliminating the primary cause of index corruption.
All Data validation rules are defined within the DBMS and enforced independently of application program logic.
Primary responsibility for Data security is now handled by the DBMS providing user based security down to the attribute level.
All aspects of multi-user access are handled by the DBMS.
A comprehensive, integrated solution to backup and recovery is provided.
A single conceptual model of all data managed by a DBA.

15. Relational Database Management Systems
Key Constructs

16. Relations and Tuples Employees Table EMPID LNAME FNAME SEX DEPT PHONE
SALARY 23
Jones
Mark M
ITR
45000 25
Smith
Sara F
FINC
49000 26
Billings
David M
ACTG
42000 31
Dance
Ivanna F
ACTG
60000 32
Jones
Mary F
ITR
70000 35
Barker
Bob M
ACTG
44000 36
Woods
Robin M
ITR
90000 37
Jones
Mary F
FINC
56000

17. Retrieving Info from Multiple Tables
Programs Table
Employees Table
EMPID
LANGUAGE
PROFICIENCY
EMPID
LNAME
FNAME
SEX
DEPT
PHONE
SALARY 23
COBOL
GOOD 23
Jones
Mark M
ITR
45000 23
JAVA
GOOD 25
Smith
Sara F
FINC
55000 23
SQL
EXCELLENT 26
Billings
David M
ACTG
42000 31
SQL
EXCELLENT 31
Dance
Ivanna F
ACTG
60000 32
JAVA
EXCELLENT 32
Jones
Mary F
ITR
70000 32
SQL
GOOD 35
Barker
Bob M
ACTG
44000 32 VB
GOOD 36
Woods
Robin M
ITR
90000 32
COBOL
EXCELLENT 37
Jones
Mary F
FINC
56000 36 VB
EXCELLENT 36
SQL
EXCELLENT 36
JAVA
EXCELLENT
Languages Table 37
COBOL
GOOD 37
SQL
FAIR
NAME
FULLNAME
COBOL
COmmon Business Oriented Language
JAVA
JAVA
SQL
Structured Query Language VB
Visual Basic