Prideorm Framework Design (I)-data access layer design

Before introducing the ORM framework, we will introduce the design of the data access layer. The data access layer is the basis of the ORM framework. Orm only encapsulates data access operations. I divide the database into three types based on the database access objects provided by. Net:

 Code  


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 -->   ///        
  ///   Database Type 
  ///        
     Public     Enum   databasetype 
{< br> sqlserver, 
 Oracle, 
 oledb 
} 

Except SQL Server and Oracle, other databases are classified as oledb. The data access layer uses the factory mode to create the corresponding data category based on parameters.CodeAs follows:

 

 Dbhelperfactory 

     Public     Class  Dbhelperfactory
{
  Public     Static     String Connectionstring {  Get  ;  Set  ;}
  Public     Static  Databasetype dbtype {  Get  ;  Set  ;}

  Static  Dbhelperfactory ()
{
Dbtype  = Databasetype. sqlserver;
}

  ///     <Summary>  
  ///  Generate database category based on database connection string name
  ///     </Summary>  
  ///     <Param name = "connectionname"> </param>  
  ///    <Returns> </returns>  
    Public     Static  Idbhelper createdbhelper (  String  Connectionname)
{
  ///  Obtain the database connection string from the configuration file  
  Connectionstring  = Configurationmanager. connectionstrings [connectionname]. connectionstring;

  Switch  (Dbtype)
{
  Case  Databasetype. sqlserver:
  Return     New  Sqldbhelper (connectionstring );
  Case  Databasetype. Oracle:
  Return     New Oracledbhelper (connectionstring );
  Case  Databasetype. oledb:
  Return     New  Oledbhelper (connectionstring );
  Default  :
  Return     Null  ;
}
}
} 

 

The data access object is created based on the set database type and the input database connection string name. That is to say, multiple different types of databases can be used in a project, the SQL Server database is used by default. Each data category inherits a unified interface:

Idbhelper 

     Public     Interface  Idbhelper
{
  ///     <Summary>  
  ///  SQL statement
  ///    </Summary>  
    String  Commandtext {  Get  ;  Set  ;}
  ///     <Summary>  
  ///  Return multiple data records
  ///    </Summary>  
  ///     <Returns> </returns>  
  Datatable executedatatable ();
  ///     <Summary>  
  ///  Returns a single data record.
  ///    </Summary>  
  ///     <Returns> </returns>  
  Datarow executedatarow ();
  Int  Executenonquery ();
  Object  Executescalar ();
  ///     <Summary>  
  /// Add Parameters
  ///     </Summary>  
  ///     <Param name = "key">  Key  </Param>  
  ///     <Param name = "value">  Value  </Param>  
   Void  Addparameter (  String  Key,  Object  Value );
} 

 

The code is very simple, so there are not many explanations. You can refer to the source code, and there are basically comments. Now let's take a look at the usage of the data access layer:

 

 Code 

     Public  Datatable getdatatable ( String  Name)
{
  ///  Set the Database Type  
  Dbhelperfactory. dbtype  =  Databasetype. sqlserver;
  ///  Create data category  
  Idbhelper dbhelper  =  Dbhelperfactory. createdbhelper (  " Connectionstring  "  );
  String  SQL  =     "  Select * from products where name = @ name  "  ;
Dbhelper. commandtext  =  SQL;
  ///  Add Parameters  
 Dbhelper. addparameter (  "  @ Name  "  , Name );
  Return  Dbhelper. executedatatable ();
} 

It is so simple and intuitive to use.

The ORM framework has a lot of content and requires network disconnection. It is really inconvenient. It uses the switch next door, and others are going to bed. I am working on a project recently. I am busy. I have to work overtime tomorrow night. Now we will attach the source code of the data access layer and introduce the design of the orm framework next time. I like originality. Although it is not as good as others' frameworks, so flexible and powerful, I am happy to use it.

Dbaccesser.rarData access layer