悲观观定SQL Server和Oracle-.NET教程,数据库应用

/*

 author:wuxiuxiang;
email:imessage@126.com

*/

using system;
using system.data;
namespace com.cuc.wu.example
{
   public class class1
   {
  //for sql server 需要与connection相关的一个transaction的隔离级别为
    //repeatable read或serializable,对于oracle,在command中使用select for update即可
       public void lockedsqldatarow()
       {
           dataset ds = new dataset();
           sqlconnection sconn = new sqlconnection(“server=localhost;uid=sa;pwd=sa;database=pubs“);
           sconn.open();
           sqltransaction tx = new sconn.begintransaction(isolationlevel.serializable);

           sqlcommand cmd = new sqlcommand(“select * from authors“,conn,tx);
           sqldataadapter da = new sqldataadapter(cmd);
           da.fill(ds,“autors“);
           //rows locked here

           ds.tables[0].rows[1][2]=“free“;

           sqlcommandbuilder bld = new sqlcommandbuilder(da);
           da.update(ds,“authors“);
           tx.commit();
           //rows unlocked here
           da.dispose();
           conn.close();//ïôê½êí·å×êô´
       }
       public void lockedoradatarow()
       {
           dataset ds = new dataset();
           oledbconnection oconn = new oledbconnection(“provider=msdaora;data source=ocr11;user id=scott;password=tiger“);
           conn.open();

           oledbtransaction tx = oconn.begintransaction();
           oledbcommand cmd = new oledbcommand(“select * form emp for update “,conn,tx);
           
           oledbdataadapter da = new oledbdataadapter(cmd);
           da.fill(ds,“emp“);
           //rows locked here;

           ds.tables[0].rows[9][2] = “clerk“;
           oledbcommandbuilder bld = new oledbcommandbuilder(da);
           da.update(ds,“emp“);
           tx.commit();
           //rows unlocked here
           da.dispose();
           oconn.close();       
       }
   };

}