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connected vs disconnected RRS feed

  • Question

  • the more i read about connected /disconnected  the more I am confused.

    first of all is it really necessary to know this before I can do database applications; so far this is not so for me....

    Is this a window applications concept or is it also for web apps?

    does dataadaptor/ tableadaptor  automatically create and open connection to database even  if I fill dataset and then close the connection?

    can some one please show me in brief the essence of  connected/disconnected

    Sunday, May 19, 2013 8:47 PM

Answers

  • A database can be made to be shared so multiple users can access the data at the same time.  Some database are designed to have locking/unlocking to prevent conflicts in access the data and other database don't.  For example Excel and Access don't have the correct locking to prevent conflists, while SQL Server does have the correct locking.

    A database is a type of file and uses an application/driver that allows reading and writing of the data.  Normally a database wil have a front end which is the user interface and a backend which does the reading, writing, and searching of the file.  The backend will sometimes keep some of the data in memory which is the most recently accessed data and the commonly used data so it doesn't have to reads and write to the files which is time consuming.  Access and Excel are front end applications that either users the Windows Microsft Jet or ACE Driver (backend) (located in system32 folder on PC) to read and write the file.

    Depending on the driver and database the connection can be made directly to the file or through a server over the network.  When made over the network the transport layer is usually TCP and the data transfer is usually HTTP (over TCP).  I said normally because somebody always invents a different method and I don't want to cover every type of exception to the normal methods.


    jdweng

    • Marked as answer by kobosh Monday, May 20, 2013 2:45 PM
    Monday, May 20, 2013 2:29 PM

All replies

  • 'Connected' means, whatever operations you perform on the data, it will directly reflect in database. This means, there exists a live communication between you and database.

    'Disconnected' means, you will fetch a set of data and you will operate on that set rather than directly working on database. When you are openerating on disconnected data, the original data in database might have been accessed/modified.

    And this concept belongs ADO.NET which is applicable to both Windows Forms applications as well as ASP.NET.

    I hope this helps.


    Please mark this post as answer if it solved your problem. Happy Programming!

    Monday, May 20, 2013 4:53 AM
  • Connected to a database allows the program to access data from the database without opening the file.  Opening a very large database uses a lot of resources of a computer (expecialy memory) so you want to connected rather than open the file.  When you connect to to a database you use a driver like the Microsoft Jet or ACE which are windows dll in the system 32 folder.  You can also use vendors drivers like an oracle driver.  You connect you can either directly to a file or use a Server over the internet (it depends on the driver and type of database).  The connection string is used to specfy the method that is used for the connection. 

    Note : Connection ISN"T restricted to ADO.NET.  The term has been around for over 40 years while ADO.NET is a more recent term and doesn't cover every type of database.


    jdweng

    Monday, May 20, 2013 6:02 AM
  • 'Connected' means, whatever operations you perform on the data, it will directly reflect in database. This means, there exists a live communication between you and database.

    'Disconnected' means, you will fetch a set of data and you will operate on that set rather than directly working on database. When you are openerating on disconnected data, the original data in database might have been accessed/modified.

    And this concept belongs ADO.NET which is applicable to both Windows Forms applications as well as ASP.NET.

    I hope this helps.


    Please mark this post as answer if it solved your problem. Happy Programming!

    thanks; does this mean  in a web environment only "one" user is connected at specific time...meaning the database is locked for that user?
    Monday, May 20, 2013 1:52 PM
  • Connected to a database allows the program to access data from the database without opening the file.  Opening a very large database uses a lot of resources of a computer (expecialy memory) so you want to connected rather than open the file.  When you connect to to a database you use a driver like the Microsoft Jet or ACE which are windows dll in the system 32 folder.  You can also use vendors drivers like an oracle driver.  You connect you can either directly to a file or use a Server over the internet (it depends on the driver and type of database).  The connection string is used to specfy the method that is used for the connection. 

    Note : Connection ISN"T restricted to ADO.NET.  The term has been around for over 40 years while ADO.NET is a more recent term and doesn't cover every type of database.


    jdweng

    thanks but      database/file  a little bit confused
    Monday, May 20, 2013 1:59 PM
  • A database can be made to be shared so multiple users can access the data at the same time.  Some database are designed to have locking/unlocking to prevent conflicts in access the data and other database don't.  For example Excel and Access don't have the correct locking to prevent conflists, while SQL Server does have the correct locking.

    A database is a type of file and uses an application/driver that allows reading and writing of the data.  Normally a database wil have a front end which is the user interface and a backend which does the reading, writing, and searching of the file.  The backend will sometimes keep some of the data in memory which is the most recently accessed data and the commonly used data so it doesn't have to reads and write to the files which is time consuming.  Access and Excel are front end applications that either users the Windows Microsft Jet or ACE Driver (backend) (located in system32 folder on PC) to read and write the file.

    Depending on the driver and database the connection can be made directly to the file or through a server over the network.  When made over the network the transport layer is usually TCP and the data transfer is usually HTTP (over TCP).  I said normally because somebody always invents a different method and I don't want to cover every type of exception to the normal methods.


    jdweng

    • Marked as answer by kobosh Monday, May 20, 2013 2:45 PM
    Monday, May 20, 2013 2:29 PM