Installing MySql software in windows

Installing MySQL on Windows:

Default installation on any version of Windows is now much easier than it used to be, as MySQL now comes neatly packaged with an installer. Simply download the installer package, unzip it anywhere, and run setup.exe.

Default installer setup.exe will walk you through the trivial process and by default will install everything under C:\mysql.

Test the server by firing it up from the command prompt the first time. Go to the location of the mysqld server which is probably C:\mysql\bin, and type:

mysqld.exe --console

NOTE: If you are on NT, then you will have to use mysqld-nt.exe instead of mysqld.exe

If all went well, you will see some messages about startup and InnoDB. If not, you may have a permissions issue. Make sure that the directory that holds your data is accessible to whatever user (probably mysql) the database processes run under.

MySQL will not add itself to the start menu, and there is no particularly nice GUI way to stop the server either. Therefore, if you tend to start the server by double clicking the mysqld executable, you should remember to halt the process by hand by using mysqladmin, Task List, Task Manager, or other Windows-specific means.

Verifying MySQL Installation:

After MySQL has been successfully installed, the base tables have been initialized, and the server has been started, you can verify that all is working as it should via some simple tests.

Use the mysqladmin Utility to Obtain Server Status:

Use mysqladmin binary to check server version. This binary would be available in /usr/bin on linux and in C:\mysql\bin on windows.

[root@host]# mysqladmin --version

It will produce the following result on Linux. It may vary depending on your installation:

mysqladmin  Ver 8.23 Distrib 5.0.9-0, for redhat-linux-gnu on i386

If you do not get such message, then there may be some problem in your installation and you would need some help to fix it.

Execute simple SQL commands using MySQL Client:

You can connect to your MySQL server by using MySQL client using mysql command. At this moment, you do not need to give any password as by default it will be set to blank.

So just use following command

[root@host]# mysql

It should be rewarded with a mysql> prompt. Now, you are connected to the MySQL server and you can execute all the SQL command at mysql> prompt as follows:

mysql> SHOW DATABASES;
+----------+
| Database |
+----------+
| mysql    |
| test     |
+----------+
2 rows in set (0.13 sec)

Post-installation Steps:

MySQL ships with a blank password for the root MySQL user. As soon as you have successfully installed the database and client, you need to set a root password as follows:

[root@host]# mysqladmin -u root password "new_password";

Now to make a connection to your MySQL server, you would have to use the following command:

[root@host]# mysql -u root -p
Enter password:*******

UNIX users will also want to put your MySQL directory in your PATH, so you won't have to keep typing out the full path every time you want to use the command-line client. For bash, it would be something like:

export PATH=$PATH:/usr/bin:/usr/sbin

Running MySQL at boot time:

If you want to run MySQL server at boot time, then make sure you have following entry in /etc/rc.local file.

/etc/init.d/mysqld start

Definition of Mysql and Database

MySQL runs on virtually all platforms, including Linux, UNIX, and Windows. Although it can be used in a wide range of applications, MySQL is most often associated with web-based applications and online publishing and is an important component of an open source enterprise stack called LAMP. LAMP is a Web development platform that uses Linux as the operating system, Apache as the Web server, MySQL as the relational database management system and PHP as the object-oriented scripting language. (Sometimes Perl or Python is used instead of PHP.)MySQL, which was originally conceived by the Swedish company MySQL AB, was acquired byOracle in 2008.  Developers can still use MySQL under the GNU General Public License (GPL), but enterprises must obtain a commercial license from Oracle.

Offshoots of MySQL are called forks. They include: 

Drizzle – a lightweight open source database management system in development based on MySQL 6.0.

What is Database?

A database is a separate application that stores a collection of data. Each database has one or more distinct APIs for creating, accessing, managing, searching and replicating the data it holds.

Other kinds of data stores can be used, such as files on the file system or large hash tables in memory but data fetching and writing would not be so fast and easy with those types of systems.

So nowadays, we use relational database management systems (RDBMS) to store and manage huge volume of data. This is called relational database because all the data is stored into different tables and relations are established using primary keys or other keys known as foreign keys.

A Relational DataBase Management System (RDBMS) is a software that:

• Enables you to implement a database with tables, columns and indexes.
• Guarantees the Referential Integrity between rows of various tables.
• Updates the indexes automatically.
• Interprets an SQL query and combines information from various tables.

RDBMS Terminology:

Before we proceed to explain MySQL database system, let's revise few definitions related to database.

• Database: A database is a collection of tables, with related data.
• Table: A table is a matrix with data. A table in a database looks like a simple spreadsheet.
• Column: One column (data element) contains data of one and the same kind, for example the column postcode.
• Row: A row (= tuple, entry or record) is a group of related data, for example the data of one subscription.
• Redundancy: Storing data twice, redundantly to make the system faster.
• Primary Key: A primary key is unique. A key value can not occur twice in one table. With a key, you can find at most one row.
• Foreign Key: A foreign key is the linking pin between two tables.
• Compound Key: A compound key (composite key) is a key that consists of multiple columns, because one column is not sufficiently unique.
• Index: An index in a database resembles an index at the back of a book.
• Referential Integrity: Referential Integrity makes sure that a foreign key value always points to an existing row.

MySQL Database:

MySQL is a fast, easy-to-use RDBMS being used for many small and big businesses. MySQL is developed, marketed, and supported by MySQL AB, which is a Swedish company. MySQL is becoming so popular because of many good reasons:

• MySQL is released under an open-source license. So you have nothing to pay to use it.
• MySQL is a very powerful program in its own right. It handles a large subset of the functionality of the most expensive and powerful database packages.
• MySQL uses a standard form of the well-known SQL data language.
• MySQL works on many operating systems and with many languages including PHP, PERL, C, C++, JAVA, etc.
• MySQL works very quickly and works well even with large data sets.
• MySQL is very friendly to PHP, the most appreciated language for web development.
• MySQL supports large databases, up to 50 million rows or more in a table. The default file size limit for a table is 4GB, but you can increase this (if your operating system can handle it) to a theoretical limit of 8 million terabytes (TB).
• MySQL is customizable. The open-source GPL license allows programmers to modify the MySQL software to fit their own specific environments.

Before You Begin:

Before you begin this tutorial, you should have a basic knowledge of the information covered in our PHP and HTML tutorials.

This tutorial focuses heavily on using MySQL in a PHP environment. Many examples given in this tutorial will be useful for PHP Programmers.

What is Database?

A database is a separate application that stores a collection of data. Each database has one or more distinct APIs for creating, accessing, managing, searching and replicating the data it holds.

Other kinds of data stores can be used, such as files on the file system or large hash tables in memory but data fetching and writing would not be so fast and easy with those types of systems.

So nowadays, we use relational database management systems (RDBMS) to store and manage huge volume of data. This is called relational database because all the data is stored into different tables and relations are established using primary keys or other keys known as foreign keys.

A Relational DataBase Management System (RDBMS) is a software that:

• Enables you to implement a database with tables, columns and indexes.
• Guarantees the Referential Integrity between rows of various tables.
• Updates the indexes automatically.
• Interprets an SQL query and combines information from various tables.

RDBMS Terminology:

Before we proceed to explain MySQL database system, let's revise few definitions related to database.

• Database: A database is a collection of tables, with related data.
• Table: A table is a matrix with data. A table in a database looks like a simple spreadsheet.
• Column: One column (data element) contains data of one and the same kind, for example the column postcode.
• Row: A row (= tuple, entry or record) is a group of related data, for example the data of one subscription.
• Redundancy: Storing data twice, redundantly to make the system faster.
• Primary Key: A primary key is unique. A key value can not occur twice in one table. With a key, you can find at most one row.
• Foreign Key: A foreign key is the linking pin between two tables.
• Compound Key: A compound key (composite key) is a key that consists of multiple columns, because one column is not sufficiently unique.
• Index: An index in a database resembles an index at the back of a book.
• Referential Integrity: Referential Integrity makes sure that a foreign key value always points to an existing row.

MySQL Database:

MySQL is a fast, easy-to-use RDBMS being used for many small and big businesses. MySQL is developed, marketed, and supported by MySQL AB, which is a Swedish company. MySQL is becoming so popular because of many good reasons:

• MySQL is released under an open-source license. So you have nothing to pay to use it.
• MySQL is a very powerful program in its own right. It handles a large subset of the functionality of the most expensive and powerful database packages.
• MySQL uses a standard form of the well-known SQL data language.
• MySQL works on many operating systems and with many languages including PHP, PERL, C, C++, JAVA, etc.
• MySQL works very quickly and works well even with large data sets.
• MySQL is very friendly to PHP, the most appreciated language for web development.
• MySQL supports large databases, up to 50 million rows or more in a table. The default file size limit for a table is 4GB, but you can increase this (if your operating system can handle it) to a theoretical limit of 8 million terabytes (TB).
• MySQL is customizable. The open-source GPL license allows programmers to modify the MySQL software to fit their own specific environments.

Before You Begin:

Before you begin this tutorial, you should have a basic knowledge of the information covered in our PHP and HTML tutorials.

This tutorial focuses heavily on using MySQL in a PHP environment. Many examples given in this tutorial will be useful for PHP Programmers.

Connected and disconnected mode

Connected and Disconnected Data Access Architecture

The ADO.NET Framework supports two models of Data Access Architecture, Connection Oriented Data Access Architecture and Disconnected Data Access Architecture.

In Connection Oriented Data Access Architecture the application makes a connection to the Data Source and then interact with it through SQL requests using the same connection. In these cases the application stays connected to the database system even when it is not using any Database Operations.

ADO.Net solves this problem by introduces a new component called Dataset. The DataSet is the central component in the ADO.NET Disconnected Data Access Architecture. A DataSet is an in-memory data store that can hold multiple tables at the same time. DataSets only hold data and do not interact with a Data Source. One of the key characteristics of the DataSet is that it has no knowledge of the underlying Data Source that might have been used to populate it.

  DataSet ds = new DataSet();

In Connection Oriented Data Access, when you read data from a database by using a DataReader object, an open connection must be maintained between your application and the Data Source. Unlike the DataReader, the DataSet is not connected directly to a Data Source through a Connection object when you populate it. It is the DataAdapter that manages connections between Data Source and Dataset by fill the data from Data Source to the Dataset and giving a disconnected behavior to the Dataset. The DataAdapter acts as a bridge between the Connected and Disconnected Objects.

  SqlDataAdapter adapter = new SqlDataAdapter("sql", "connection");
  DataSet ds = new DataSet();

  adapter.Fill(ds, "Src Table");

By keeping connections open for only a minimum period of time, ADO .NET conserves system resources and provides maximum security for databases and also has less impact on system performance.

Difference between stored procedure and function.

Stored Procedure have pre-compiled execuction plan where as functions do not.

Functions are used for computations where as procedures are mainly used for performing business logic.

Functions can only have 'in' parameter where as SP can have both 'in' and 'out' parameters.

Function does not allow DML (insert, update, delete) queries on an object where as SP allows.

Functions can be used inline where as SP can't be.

Stored Procedure can retun more than one value at a time while funtion returns only one value at a time.

Functions MUST return a value, procedures need not be

Delegate in c#

            Delegate                                                

  Delegate is a special data type that hold the address or reference of a function.

There are two type of delegate.
1)single cast delegate.
2)multi cast delegate.

                    Single cast delegate.

If we are using delegate object to store single function, then we said that it is single cast delegate.

                     Multi cast delegate.

If we are using delegate object to store multiple function, then we easily said that it is multi delegate.

                         General syntax of delegate

#create delegate.

Access specifiers delegate name of delegate.
E.g:-
Public delegate my del();
#procedure to create object of delegate and hold function into it.
My del obj1=new My del ();
#calling of function using delegate object.
Obj1();= fun 1();

explanation of definition of ado.net

Ado means active data object and ado is replaced by ado.net .Ado.net is fully based on oops concept.
ADO.NET is a set of computer software components that programmers can use to access data and data services based on disconnected DataSets and XML. It is a part of the base class library that is included with the Microsoft .NET Framework. It is commonly used by programmers to access and modify data stored in relational database systems, though it can also access data in non-relational sources. ADO.NET is sometimes considered an active x data object.

difference between interface and abstract class.

Difference between interface and abstract class

Interface provide pure abstract methods.

Abstract class provide concrete classes.

Interface provide multiple inheritance.

Abstract class don't provide multiple inheritance.

We cannot create object of interface, we create only reference variable of interface.

We create object of abstract class.

We cannot define data field within interface.

In abstract class we have to define data field. 

We cannot use any access specifier within interface.

We can use access specifier with abstract class.