如何使用ADO访问Oracle数据库存储过程

2/9/2008来源:Oracle教程人气:5835


  ---- 一、关于ADO
  
  ---- 在基于Client/Server结构的数据库环境中,通过OLE DB接口可以存取数据,但它定义的是低层COM接口,不仅不易使用,而且不能被VB,VBA,VBScript等高级编程工具访问。 而使用ADO则可以很轻易地使VB等编程语言直接访问数据(通过OLE DB接口)。ADO是基于面向对象方法的,其对象模型如下图所示(略)
  
  ---- 由上图可见,ADO对象模型总共才包括六个对象,相对于数据访问对象(DAO)来说简单得多。因此实际中经常使用它来访问数据库。
  
  ---- 二、ADO访问数据库实例
  
  ---- 下面,我们以Oracle为例,使用VB6.0来访问其数据库中的存储过程。在此例中,我们首先在Oracle数据库上创建有两个存储过程,一个不带参数,另一个带有参数。然后,使用ADO来访问这两个存储过程。步骤如下:
  
  ---- 1. 在Oracle服务器上运行以下DDL脚本:
  
  DROP TABLE person;
  CREATE TABLE person
  (ssn NUMBER(9) PRIMARY KEY,
  fname VARCHAR2(15),
  lname VARCHAR2(20));
  INSERT INTO person VALUES(555662222,'Sam','Goodwin');
  INSERT INTO person VALUES(555882222,'Kent','Clark');
  INSERT INTO person VALUES(666223333,'Jane','Doe');
  COMMIT;
  /
  
  ---- 2. 在Oracle服务器上创建包(package):
  CREATE OR REPLACE PACKAGE packperson
  AS
  TYPE tssn is TABLE of NUMBER(10)
  INDEX BY BINARY_INTEGER;
  TYPE tfname is TABLE of VARCHAR2(15)
  INDEX BY BINARY_INTEGER;
  TYPE tlname is TABLE of VARCHAR2(20)
  INDEX BY BINARY_INTEGER;
  
  PROCEDURE allperson
  (ssn OUT tssn,
  fname OUT tfname,
  lname OUT tlname);
  PROCEDURE oneperson
  (onessn IN NUMBER,
  ssn OUT tssn,
  fname OUT tfname,
  lname OUT tlname);
  END packperson;
  /
  
  ---- 3. 在Oracle服务器上创建以下包体(package body):
  CREATE OR REPLACE PACKAGE BODY packperson
  AS
  PROCEDURE allperson
  (ssn OUT tssn,
  fname OUT tfname,
  lname OUT tlname)
  IS
  CURSOR person_cur IS
  SELECT ssn, fname, lname
  FROM person;
  percount NUMBER DEFAULT 1;
  BEGIN
  FOR singleperson IN person_cur
  LOOP
  ssn(percount) := singleperson.ssn;
  fname(percount) := singleperson.fname;
  lname(percount) := singleperson.lname;
  percount := percount + 1;
  END LOOP;
  END;
  PROCEDURE oneperson
  (onessn IN NUMBER,
  ssn OUT tssn,
  fname OUT tfname,
  lname OUT tlname)
  IS
  CURSOR person_cur IS
  SELECT ssn, fname, lname
  FROM person
  WHERE ssn = onessn;
  percount NUMBER DEFAULT 1;
  BEGIN
  FOR singleperson IN person_cur
  LOOP
  ssn(percount) := singleperson.ssn;
  fname(percount) := singleperson.fname;
  lname(percount) := singleperson.lname;
  percount := percount + 1;
  END LOOP;
  END;
  END;
  /
  
  ---- 4. 在 VB 6.0 中打开一个新的工程,缺省创建表单 Form1。

  ---- 5. 在表单上添加二个按钮,cmdGetEveryone和cmdGetOne。
  
  ---- 6. 在代码窗口中添加以下代码:
  
  Option EXPlicit
  Dim Cn As ADODB.Connection
  Dim CPw1 As ADODB.Command
  Dim CPw2 As ADODB.Command
  Dim Rs As ADODB.Recordset
  Dim Conn As String
  Dim QSQL As String
  Dim inputssn As Long
  
  Private Sub cmdGetEveryone_Click()
  Set Rs.Source = CPw1
  Rs.Open
  While Not Rs.EOF
  MsgBox "Person data: " & Rs(0) & ",
  " & Rs(1) & ", " & Rs(2)
  Rs.MoveNext
  Wend
  Rs.Close
  End Sub
  
  Private Sub cmdGetOne_Click()
  Set Rs.Source = CPw2
  inputssn = InputBox(
  "Enter the SSN you wish to retrieve:")
  CPw2(0) = inputssn
  Rs.Open
  MsgBox "Person data: " & Rs(0) & "
  , " & Rs(1) & ", " & Rs(2)
  Rs.Close
  End Sub
  
  Private Sub Form_Load()
  '使用合适的值代替以下用户ID,
  口令(PWD)和服务器名称(SERVER)
  Conn = "UID=*****;PWD=*****;driver=" _
  & "{Microsoft ODBC for
  Oracle};SERVER=dSEOracle;"
  Set Cn = New ADODB.Connection
  '创建Connection对象
  With Cn
  .ConnectionString = Conn
  .CursorLocation = adUseClient
  .Open
  End With
  QSQL = "{call packperson.allperson(
  {resultset 9,ssn,fname,"_
  & "lname})}"
  Set CPw1 = New ADODB.Command
  '创建Command对象
  With CPw1
  Set .ActiveConnection = Cn
  .CommandText = QSQL
  .CommandType = adCmdText
  End With
  QSQL ="{call packperson.oneperson(?,
  {resultset 2,ssn, "_
  & " fname,lname})}"
  '调用存储过程
  Set CPw2 = New ADODB.Command
  With CPw2
  Set .ActiveConnection = Cn
  .CommandText = QSQL
  .CommandType = adCmdText
  .Parameters.Append.CreateParameter(
  ,adInteger, _
  adParamInput)
  '添加存储过程参数
  End With
  Set Rs = New ADODB.Recordset
  With Rs
  .CursorType = adOpenStatic
  .LockType = adLockReadOnly
  End With
  End Sub
  
  Private Sub Form_Unload(Cancel As Integer)
  Cn.Close
  Set Cn = Nothing
  Set CPw1 = Nothing
  Set CPw2 = Nothing
  Set Rs = Nothing
  End Sub
  
  ---- 7. 运行程序。当点下cmdGetEveryone按钮时,程序调用Oracle数据库中不带参数的存储过程packperson.allperson,点下cmdGetOne按钮时调用packperson.oneperson存储过程。