Class 12 Computer Science Chapter 6 Notes

• Describe MS Access? Describe Benefits of MS Access: In a relational database the data is stored in tables. The TABLE or RELATION is a fundamental concept of relational databases. It is foundation of every Relational Database Management System. Tables are grids that store information in a database similar to the way an Excel worksheet stores information in a workbook. Access provides three ways to create a table for which there are icons in the Database Window. Double-click on any of the icons to create a table. Every database consists of one or more tables which store data. Each table has its own unique name and consists of columns and rows. It is a very convenient way to store information. The columns in a table (also called table fields) have their own unique names and have a pre-defined data type. The field can be a primary key, an index defined on it and it can have certain default value. The table columns describe the data types, whereas the table rows contain the actual data. 
• Describe Characteristics of Database Tables? Answer : Characteristics of Tables The tables of a relational database have following characteristics: 1. Each cell of the table contains only one value. 2. Each colunm has a distinct name, which is the name of the attribute (field) it represents. 3. The order of the columns is immaterial. 4. Each row represents a record. 5. Each row is distinct; there are no duplicate rows. 6. The order of rows is immaterial. 7. Using a separate table for each entity means that you store that data only once, which makes your database more efficient, and reduces data entry errors. Tables form the foundation of an Access database structure.
• Describe MS Access IDE? Answer : Access IDE IDE stand for Integrated Development Environment. It is an interface that is used to create a database. An IDE makes the using of database simple, manageable for end users who may not have a complicate programming knowledge of the database system. Microsoft Access is an example of a database management system. The access IDE simplifies the task of creating, designing good-looking screens with features (i.e. text boxes, list boxes, button, dialog boxes etc.). It provides the facilities for searching, sorting, and retrieving the data. 
• Describe Query in MS Access? Answer : Query in MS Access Query mean question or inquiry. The questions like statements that are to retrieve data form one or more database tables are called queries. It is a powerful and flexible way of selecting, filtering and sorting records. Queries select records from one or more tables in a database; these selected records can be viewed, analyzed, and sorted on a common datasheet. The resulting collection of records, called a dynaset (short for dynamic subset), is saved as a database object and can therefore be easily used in future. The query will be updated whenever the original tables are updated. Types of queries are select queries that extract data from tables based on specified values, find d queries that display records with duplicate values for one or more of the specified fields, and find unmatched queries display records from one table that do not have corresponding values in a second table. 
• Describe Degree and Cardinality of Relation or Table.
• Define Basic Term used in Database.
• Describe Data Types in MS Access.
• Explain Types of Query in MS Access.