OT: Database Version Check

I did exact same thing before, although not using CSLA.  I put my check into a class that was called from Sub Main().  If DB was too new, software would display a message and fold (Application.Exit(), Exit Sub).

Sergey Barskiy

Principal Consultant

office: 678.405.0687 | mobile: 404.388.1899

Magenic ®

Microsoft Worldwide Partner of the Year | Custom Development Solutions, Technical Innovation

Hello everyone,
Quick question... Currently, out database has a table in it called "DatabaseVersion".  This table just holds a version number that we change as the database changes (I.E.- 1.0.0.2).

Basically, I need the software to check this value to make sure the version of the software they are running is compliant with the version of the database. (I know it sounds like this shouldn't happen, but it does in our situation)

If it were you, where in your code would you put a check like this?

Anyone do anything similar?  Any tips or ideas would be greatly appreciated.

Thanks!

Sergey,

I think that the question is more like, since all of the DB communication goes through  Csla Business layer, what type of object would you use to get the database version.  If that was truly the question, then my answer would be: use CommandObject, and place  the Database version in a Result property of it:

Usage being:

string dbVersion =  DBVersionCommand.Execute();

and obviously server side implementation – data access part goes to DBVersionCommand.DataPortalExecute()

Nermin

I did exact same thing before, although not using CSLA.  I put my check into a class that was called from Sub Main().  If DB was too new, software would display a message and fold (Application.Exit(), Exit Sub).

Sergey Barskiy

Principal Consultant

office: 678.405.0687 | mobile: 404.388.1899

Magenic ®

Microsoft Worldwide Partner of the Year | Custom Development Solutions, Technical Innovation

Hello everyone,
Quick question... Currently, out database has a table in it called "DatabaseVersion".  This table just holds a version number that we change as the database changes (I.E.- 1.0.0.2).

Basically, I need the software to check this value to make sure the version of the software they are running is compliant with the version of the database. (I know it sounds like this shouldn't happen, but it does in our situation)

If it were you, where in your code would you put a check like this?

Anyone do anything similar?  Any tips or ideas would be greatly appreciated.

Thanks!

Yes you have an object inheriting from CommandBase, implement DataPortal_Execute (db SP call that returns the ver. number), static Execute is your FactoryMethod that returns the version number, on the client side (and internally calls DataPortal.Execute<DBVersionCommand>(obj)), you will have to have a Result field property to serialize the value back from DataPortal_Execute to Execute(), and that is essentially it.

Wow...thanks everyone for the replies... sounds like I'm on the right track.

Nermin, I was thinking command object would be the way to go.  So basically I have an object that inherits from command object and it's sole responsibility is to get this value... does that seem right?

Thanks again for the responses :)

My bad.  I totally agree.

Sergey,

I think that the question is more like, since all of the DB communication goes through  Csla Business layer, what type of object would you use to get the database version.  If that was truly the question, then my answer would be: use CommandObject, and place  the Database version in a Result property of it:

Usage being:

string dbVersion =  DBVersionCommand.Execute();

and obviously server side implementation – data access part goes to DBVersionCommand.DataPortalExecute()

Nermin

I did exact same thing before, although not using CSLA.  I put my check into a class that was called from Sub Main().  If DB was too new, software would display a message and fold (Application.Exit(), Exit Sub).

Sergey Barskiy

Principal Consultant

office: 678.405.0687 | mobile: 404.388.1899

Magenic ®

Microsoft Worldwide Partner of the Year | Custom Development Solutions, Technical Innovation

Hello everyone,
Quick question... Currently, out database has a table in it called "DatabaseVersion".  This table just holds a version number that we change as the database changes (I.E.- 1.0.0.2).

Basically, I need the software to check this value to make sure the version of the software they are running is compliant with the version of the database. (I know it sounds like this shouldn't happen, but it does in our situation)

If it were you, where in your code would you put a check like this?

Anyone do anything similar?  Any tips or ideas would be greatly appreciated.

Thanks!

More generalized, meaning outside of csla, right?  I would recommend against that approach.  I find the CommandBase simple enough, and more importantly one has to think about the value of Csla where code can be easily ported to run on a separate physical servers.  If you move your code to a “more generalized commands” you loose that flexibility, you can not port your code from running locally to a multi-layer solution without having to change it.

Lets assume that your “generalized command” executes on a DAL, that runs on Application server – how do you pass it to the client, which lets say is a WinForm on another machine?  Generalized solution then has to assume only a single layer app, or it has to “invent” a new object or a set of objects that communicate the result back to the client.

 Or perhaps I am missing something here?

Nermin

nermin:

...what type of object would you use to get the database version.  If that was truly the question, then my answer would be: use CommandObject, and place  the Database version in a Result property of it:

...

You might also find it handy as you do this to have more generalized commands that can invoke an arbitrary stored procedure and return the result, or fetch a specific scalar value given an arbitrary SQL statement. 

Looks good – only one thing:  I would make constructor private.  That way the Factory method is the only way to get to the instance of the Command object.

Nermin

Okay... I think I have it working.  Does the following look correct.  It's my first attempt at a commandbase type object.


&nbsp;&nbsp;&nbsp; &lt;Serializable()&gt; _
&nbsp;&nbsp;&nbsp; Public Class DatabaseVersionCommand
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Inherits Csla.CommandBase

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Private _databaseVersion As String
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Public ReadOnly Property DatabaseVersion() As String
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Get
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Return _databaseVersion
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; End Get
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; End Property
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Public Sub New()
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; End Sub

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Public Shared Function Execute() As String
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Dim cmd As New DatabaseVersionCommand
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; cmd = Csla.DataPortal.Execute(Of DatabaseVersionCommand)(cmd)
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Return cmd.DatabaseVersion
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; End Function

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Protected Overrides Sub DataPortal_Execute()
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Using cn As New SqlConnection(GetConnectionString)
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; cn.Open()
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Using cm As SqlCommand = cn.CreateCommand
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; cm.CommandType = CommandType.Text
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; cm.CommandText = "SELECT DATABASE_VERSION FROM VERSION"
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Dim version As String = TryCast(cm.ExecuteScalar, String)
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; _databaseVersion = version
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; End Using
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; End Using
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; End Sub

&nbsp;&nbsp;&nbsp; End Class

I actually do like that idea!  Sorry for miss-interpreting your thoughts in my original reply. 

nermin:

More generalized, meaning outside of csla, right?  I would recommend against that approach.  I find the CommandBase simple enough, and more importantly one has to think about the value of Csla where code can be easily ported to run on a separate physical servers. 

No, it's still a CSLA CommandBase, just a more general one as opposed to one that just invokes a specific stored procedure.

For example, (just to illustrate), you could write a single CommandBase class to execute any parameterless stored procedure. Then you could implement a static Execute method on the class that just takes the procedure name.  You can even make this generic so that the type of the result can be specified (e.g. you might be getting back a date, int, string, etc.).

I'm a big fan of leveraging CSLA to do as much as possible, so no I wasn't proposing a non-CSLA solution.