Data Base iN ADO.net

What is a dataset?
A dataset is the local repository of the data used to store the tables and disconnected record set. When using disconnected architecture, all the updates are made locally to dataset and then the updates are performed to the database as a batch.
What is a data adapter?
A data adapter is the component that exists between the local repository (dataset) and the physical database. It contains the four different commands (SELECT, INSERT, UPDATE and DELETE). It uses these commands to fetch the data from the DB and fill into the dataset and to perform updates done in the dataset to the physical database. It is the data adapter that is responsible for opening and closing the database connection and communicates with the dataset.
What is a database connection?
A database connection represents a communication channel between you application and database management system (DBMS). The application uses this connection to pass the commands and queries to the database and obtain the results of the operations from the database.
What is a database command?
A database command specifies which particular action you want to perform to the database. The commands are in the form of SQL (Structured Query Language). There are four basic SQL statements that can be passed to the database.
SQL SELECT Statement
This query is used to select certain columns of certain records from a database table.

SELECT * from emp// sql steaments

selects all the fields of all the records from the table name ‘emp’

SELECT empno, ename from emp
selects the fields empno and ename of all records from the table name ‘emp’

SELECT * from emp where empno <>
selects all those records from the table name ‘emp’ that have the value of the field empno less than 100

SELECT * from article, author where article.authorId = author.authorId
selects all those records from the table name ‘article’ and ‘author’ that have same value of the field authorId
SQL INSERT Statement
This query is used to insert a record to a database table.

INSERT INTO emp(empno, ename) values(101, ‘John Guttag’)
inserts a record to emp table and set its empno field to 101 and its ename field to ‘John Guttag’
SQL UPDATE Statement
This query is used to edit an already existing record in a database table.

UPDATE emp SET ename =‘Eric Gamma’ WHERE empno = 101
updates the record whose empno field is 101 by setting its ename field to ‘Eric Gamma’
SQL DELETE Statement
This query is used to delete the existing record(s) from the database table

DELETE FROM emp WHERE empno = 101
deletes the record whose empno field is 101 from the emp table
What is a data reader?
The data reader is a component that reads the data from the database management system and provides it to the application. The data reader works in the connected manner; it reads a record from the DB, pass it to the application, then reads another and so on.
How do different components of ADO.Net interact with each other in disconnected architecture?
The Data Adapter contains in it the Command and Connection object. It uses the connection object to connect to the database, execute the containing command, fetch the result and update the DataSet.

What does it mean by Dot Net Framework Data Provider?
Dot Net Framework Data Provider is a set of classes that establishes the database communication between an application and the database management system based on the standards of ADO.Net framework. Different data providers provide specialized and optimized connectivity to particular database management system or to a particular class of DBMS. For example, the MS SQL Server data provider provides the optimized connectivity between dot net application and MS SQL Server DBMS while the OLEDB data provider provides the uniform connectivity between dot net application and the OLEDB databases.