This document discusses the basics of database management systems (DBMS). It begins by explaining the data storage hierarchy from the bit level up to the database level. It then covers different database models including hierarchical, network, relational, and object-oriented. Key components of a DBMS like DDL, DML, query language, and report generators are defined. Commercial DBMS examples are provided. The document concludes with an overview of creating and using a database, including defining the structure, entering data, and searching for information.

1. DBMS

3. Character: Multiple related bits are combine to form a character(M,8,$..etc).

4. Field: Multiple related character are combine to form field. (employee code, emp name).

7. The commonly used database model are:Hierarchical Database. Network Database. Relational Database. Object Oriented Database.

9. Root at the top.

10. Parent-child relationship

11. Parent data element is one and can have one or more subordinate or child element.

13. The main limitation is, it does not support flexible data access because the data can only be accessed by following the tree structure.

15. It follows parent-child relationship.

16. The mapping of data and their relationship is very important when the database is first design.

17. Here the child data can have more than one parent and can have no parent at all.

19. Each table represents separate file.

20. Each table column are represent as field.

21. Each table row are represent as data record.

27. Data Manipulation Language (DML)

28. Query Language

30. Defining data element field and records.

31. Defining the name, field length, and field type for each data type.

32. Defining control for field that can have only selective values.

33. Defining the logical relationship among various data element.

35. This description can be use by system analyst in defining new application.

37. He have the overall authority to establish and control data definition and Standard.

38. He is responsible for determining relationship among data element and designing database security.

39. He also train programmer to use database.

41. Data Manipulation Language (DML) includes the command to enter and manipulate the Data, with these commands the user can perform the following,

44. Creating and Using Database Defining its Structure (Schema). Designing Forms. Entering Data in it.

45. Defining its Structure (Schema). Here we list down all the field required in a database. Determine name type and size of each field. This information is captured in the system by the tool called schema builder. (schema builder help the user to define the database schema by prompting the user to enter the field type, field size and so on…) Modification is always possible be it is always better to design the database carefully in 1st instance and minimize the need to modify.

47. Validation check: to ensure the corectness of entered data.

48. Automatic conversions: like upper to lower case.

51. Data is entered one record at a time.

56. Query lang can be easily learnt and used even by non programmer.