VB.NET学习（二）数据库操作

1. 建立数据源的链接
   
   • Imports  System.Web.Services
     Imports  System.EnterpriseServices
     Imports  Oracle.DataAccess.Client
     Imports  Oracle.DataAccess.Types
     Imports  System.Configuration
     Imports  System.Net
     Imports  System.Web
     Imports  System.Xml
     
          Private  OraConn  As   New  OracleConnection
          Private  OraCmd  As   New  OracleCommand
          Private  UserID  As   String
          Private  Password  As   String
          Private  DataSource  As   String
          Private  OraTrans  As  OracleTransaction
     
          < WebMethod() >  _
          Public   Function  OpenOraDatabase()  As   Boolean
     
             UserID  =  ConfigurationSettings.AppSettings( " UserID " )
             Password  =  ConfigurationSettings.AppSettings( " Password " )
             DataSource  =  ConfigurationSettings.AppSettings( " DataSource " )
     
             OraConn.ConnectionString  =   " user id= "   &  UserID  &   " ;password= "   &  Password  &   " ;data source= "   &  DataSource
             OraConn.Open()
             OraCmd.Connection  =  OraConn
     
          End Function
   • Imports  System.Web.Services
     Imports  System.EnterpriseServices
     Imports  System.Configuration
     Imports  System.Net
     Imports  System.Web
     Imports  System.Xml
     Imports  System.Text
     Imports  System.Runtime.InteropServices
     Imports  System.Threading
     
             Private  OraConn  As   New  OleDb.OleDbConnection
              Private  OraCmd  As   New  OleDb.OleDbCommand
              Private  UserID  As   String
              Private  Password  As   String
              Private  DataSource  As   String
              Private  OraTrans  As  OleDb.OleDbTransaction
              Private  OraDa2  As  OleDb.OleDbDataAdapter
     
              < WebMethod() >  _
              Public   Function  OpenOraDatabase()  As   Boolean
     
                 UserID  =  ConfigurationSettings.AppSettings( " DenUserID " )
                 Password  =  ConfigurationSettings.AppSettings( " DenPassword " )
                 DataSource  =  ConfigurationSettings.AppSettings( " DenDataSource " )
     
                 OraConn.ConnectionString  =   " Provider=MSDAORA.1;user id= "   &  UserID  &   " ;password= "   &  Password  &   " ;data source= "   &  DataSource
                 OraConn.Open()
                 OraCmd.Connection  =  OraConn
     
              End Function
2. 关闭连接
   
   
            < WebMethod() >  _
            Public   Function  CloseOraDatabase()  As   Boolean
   
               OraConn.Close()
   
            End Function
3. 事务处理
   
   • WebService定义
     
             < WebMethod() >  _
              Public   Sub  BeginTrans()
                 
                 OraTrans.Dispose()
                 OraTrans  =  OraConn.BeginTransaction(IsolationLevel.ReadCommitted)
     
              End Sub
     
              < WebMethod() >  _
              Public   Sub  CommitTrans()
     
                 OraTrans.Commit()
     
              End Sub
     
              < WebMethod() >  _
              Public   Sub  RollbackTrans()
     
                 OraTrans.Rollback()
     
              End Sub
   • 客户端调用
     
     Private   Function  WriteData()
              Dim  wSMgt  As   New  ServiceManagemet
     
             wSMgt.OpenOraDatabase()
             wSMgt.BeginTrans()
     
              Try
                 aSql  =   ""
     
                 wSMgt.OraCmd.CommandText  =  aSql
                 wSMgt.OraCmd.ExecuteNonQuery()
     
                  Next
     
                 wSMgt.CommitTrans()
     
              Catch  ex  As  Exception
                 wSMgt.RollbackTrans()
              Finally
                 wSMgt.CloseOraDatabase()
              End   Try
     End Function
     
     
   • 服务器端事务处理
     
                 OpenOraDatabase()
     
                 OraTrans  =  OraConn.BeginTransaction()
                 OraCmd.Transaction  =  OraTrans
                  Try
             
                      ' 打开记录集
                     aSql  =   ""
                     OraCmd.CommandText  =  aSql
                     OraDa2  =   New  OleDb.OleDbDataAdapter(OraCmd)
                     OraDa2.Fill(aDS,  " TableName " )
                      If  aDS.Tables( " TableName " ).Rows.Count  <>   0   Then
     
                     ' 执行SQL命令
                     OraCmd.CommandText  =  aSql
                     OraCmd.ExecuteNonQuery()
     
                     OraTrans.Commit()
                  Catch  ex  As  Exception
                     OraTrans.Rollback()
                  Finally
                     CloseOraDatabase()
                  End   Try
4. 执行SQL命令
   
   
   • 建立连接
     
     
          Private   Function  ConnectOraDatabase()  As   Boolean
     
             UserID  =  ConfigurationSettings.AppSettings( " UserID " )
             Password  =  ConfigurationSettings.AppSettings( " Password " )
             DataSource  =  ConfigurationSettings.AppSettings( " DataSource " )
     
             OraConn.ConnectionString  =   " user id= "   &  UserID$  &   " ;password= "   &  Password$  &   " ;data source= "   &  DataSource$
             OraCmd.Connection  =  OraConn
     
          End Function
   • 获得记录集
     
          < WebMethod() >  _
          Public   Function  GetData( ByVal  aSql  As   String ,  ByVal  aTab  As   String ,  ByRef  aDs  As  DataSet)  As   Boolean
     
              Dim  aRet  As   Boolean
     
             ConnectOraDatabase()
     
             OraCmd.CommandText  =  aSql
     
              Dim  OraDa  As   New  OracleDataAdapter(OraCmd)
              If  aDs.Tables.Contains(aTab)  Then  aDs.Tables(aTab).Clear()
             OraDa.Fill(aDs, aTab)
     
              If  aDs.Tables(aTab).Rows.Count  =   0   Then
                 aRet  =   False
              Else
                 aRet  =   True
              End   If
     
             CloseOraDatabase()
     
              Return  aRet
     
          End Function
   • 执行SQL命令
     
          < WebMethod(TransactionOption: = TransactionOption.RequiresNew) >  _
          Public   Sub  UpdateData( ByVal  aSql  As   String )
             OpenOraDatabase()
             OraCmd.CommandText  =  aSql
             OraCmd.ExecuteNonQuery()
             CloseOraDatabase()
     
          End Sub
   • 执行包
     
             OpenOraDatabase()
     
             OraCmd.CommandText  =   " PACKNAME.PROCENAME "
             OraCmd.CommandType  =  CommandType.StoredProcedure
     
              Dim  paramSESSIONID  As  OracleParameter  =  OraCmd.Parameters.Add( _
               New  OracleParameter( " inSESSIONID " , OracleDbType.Char, ParameterDirection.Input))
     
         OraCmd.Parameters( " inSESSIONID " ).Value  =  inSESSIONID
     
             OraCmd.ExecuteNonQuery()
     
             CloseOraDatabase()