浅析C#绑定变量和匿名块获取获取序列当前值

我们将谈到C#绑定变量和匿名块获取获取序列当前值，首先需要在Oracle中进行一系列的操作，接下来是C#绑定变量的具体操作。

1.在Oracle中建立表、序列、触发器：

SQL> create table TESTTAB  
   (  
     ID   NUMBER,  
     NAME VARCHAR2(10)  
   ); 

表被创建

SQL> create sequence TESTTABSEQ  
    minvalue 1  
    maxvalue 999999999999999999999999999  
   start with 1  
    increment by 1  
    cache 20; 

序列被创建

SQL> create or replace trigger Tr_testtabid  
   before insert on testtab for each row  
      
    begin 
     SELECT TESTTABSEQ.NEXTVAL into :NEW.id from dual;  
     end Tr_testtabid;  
    / 

触发器被创建

2.主要的C#绑定变量代码：

using ORAC = System.Data.OracleClient;  
        private void button1_Click(object sender, System.EventArgs e)  
                {  
                        try 
                        {  
                          
                                string str_Sql = @"begin insert into testtab(name) values('test'); select TESTTABSEQ.Currval into :ID from dual; end;";  
                                ORAC.OracleCommand cmd= new ORAC.OracleCommand(str_Sql,this.oracleConnection1);  
 
                                ORAC.OracleParameter parm = new ORAC.OracleParameter("ID",ORAC.OracleType.Number);  
                                parm.Direction = ParameterDirection.Output;  
                                cmd.Parameters.Add(parm);  
 
                                if(this.oracleConnection1.State == System.Data.ConnectionState.Closed)  
                                {  
                                        this.oracleConnection1.Open();  
                                }  
                                cmd.ExecuteNonQuery();  
 
 
                                this.textBox1.Text = cmd.Parameters[0].Value.ToString();  
                        }  
                        catch(Exception ex)  
                        {  
                                MessageBox.Show("发生错误！";  
                                  
                        }  
                        finally 
                        {  
                                this.oracleConnection1.Close();  
                        }  
 
                          
                }