vb怎么连接数据库库

VB使用ADO数据库可以分为有源数据库和无源数据库，即是否使用了DSN数据源，如下例：

1、在连接数据库前首先要在VB菜单中“工程”-“引用”从中选择 microsoft activeX Data objects 2.6 library和 microsoft activeX Data objects recordset 2.6两个组件，这是在连接数据前所必做的工作。

2、接下来定义ADO的连接对象，如下所示：

Set conn = New ADODB.Connection

Set rs = New ADODB.Recordset

第一种方法采用的是无源的数据库连接方法

conn.ConnectionString = "Driver={sql server}server=JSZX3-11uid=sapwd=database=wzc"

conn.ConnectionTimeout = 30

conn.Open

rs.Open "select 用户名,密码 from login where 用户名='" &Trim(Combo1.Text) &"' And 密码='" &Trim(Text1.Text) &"'", conn, adOpenStatic, adLockReadOnly, adCmdText

If rs.EOF = True And rs.BOF Then

m = MsgBox("请重新登录", vbExclamation)

Text1.Text = ""

Text1.SetFocus

Else

Form1.Hide

End If

rs.Close

这是第二种方法连接数据库的方法，这一种方法是采用有源的方法与数据库连接的方法，代码如下所示：

Set conn = New ADODB.Connection

Set rs = New ADODB.Recordset

conn.ConnectionString = "DSN=loginuid=sapwd="

conn.ConnectionTimeout = 30

conn.Open

rs.Open "select 用户名 from login", conn, adOpenStatic, adLockReadOnly, adCmdText

Dim i As String

For t = 0 To Val(rs.RecordCount) - 1

i = Trim(rs.Fields("用户名").Value)

rs.MoveNext

Combo1.AddItem i

Next t

rs.Close

dim

dbConn

As

ADODB.Connection

'定义一个ADODB连接

dim

MenuRs

As

ADODB.Recordset

'定义Recordset对象

dim

WordRs

As

ADODB.Recordset

Function

Conn2DB(byval

dbname

as

string)

As

Boolean

'数据库连函数，dbname为数据库文件的绝对路径

Dim

connStr

As

String

'

Access连接字符串

conStr

=

"Provider=Microsoft.Jet.OLEDB.4.0Data

Source="

&

dbName

&

"Persist

Security

Info=FalseJet

OLEDB:Database

Password=abcdef"

Set

dbConn

=

New

ADODB.Connection

'定义一个ADODB连接对象

If

dbConn.State

<>

adStateOpen

Then

'判断ADODB连接是否打开

dbConn.Open

conStr

'如果不是打开状态

就打开连接

End

If

Conn2DB

=

True

End

Function

Function

CloseDb()

As

Boolean

If

dbConn.State

=

adStateOpen

Then

dbConn.Close:

Set

dbConn

=

Nothing

End

If

End

Function

Private

Sub

Form_Load()

dim

dbname

as

string

dbname="D:\db.mdb"

‘数据库文件路径

if

Conn2DB(dbname)=true

then

msgbox

"连接数据库成功!"

CloseDb

end

if

End

sub

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