VB connects to the database

2. Whether the user's password is text2, whether to transfer to the next step, whether to exit;

3. Follow-up operations.

PS: Look at "My Messages".

Dizzy. This is a bit long.,It's not clear to say.,It's recommended that you go to msdn to see.,If it's not installed.,You can search for msdn in it.,There must be a typical case in it! You can see what is written in the case!

VB connects to the database. Check the username and password. If the input is incorrect three times, the program exits.

option explicit

dim cnt as integer 'Record the number of determinations.

private sub cmdcancle_click()

unload me

end sub

private sub cmdok_click()

dim sql as string

dim rs_login as new

dim conn as new

provider=; data source=" & "Fixed. mdb"

if trim( = "" then

msgbox "The username cannot be empty, please re-enter it! "

elsesql = "select * from user table where user id='" & trim( &"'"

rs_ sql, conn, adopenkeyset, adlockpessimistic

if rs_ = true then

msgbox "If you don't have this user, please re-enter! ", vbokonly + vbexclamation, ""

elseusername =

if trim(rs_ = trim( then

unload me

elsemsgbox "The password is incorrect, please re-enter it! ", vbokonly + vbexclamation, ""

end if

end if

end if

cnt = cnt + 1

if cnt = 3 then

unload me

end if

end sub

private sub form_keypress(keyascii as integer)

if keyascii = 13 then

call cmdok_click

end if

end sub

private sub form_load()

cnt = 0

end sub

dim mm1 as string

dim user1 as string

user1 = trim(

mm1 = trim(

if user1 = "" or mm1 = "" thenrespone = msgbox("Username and password can't be empty! ", vbyes, "Prompt! ")

elsesql = "select count(*)from table name where username field ='" + user1 + "'"

set rs =

if rs(0) <0 then

sql = "select password field from table name where password field ='" + mm1 + "'"

set rs =

if mm1 = rs(1) then

Form. show

end if

elsemsgbox "The username does not exist, please re-enter it! "

end if

end if

Ways to add parts: Microsoft Ado Data Control

Add an ADODC control to the form, then set the properties of the ADODC control, select "Generate" on the side of the "Use Connection String" item, then select the oracle driver, and set other conditions (libraries, users, passwords, etc.), copy out the generated string, assign the value, and then you can delete the ADODC control.

You can connect to the Oracle database through the property page of the ADodC data access control.

1) Create a data project and add an ADODC data access control to the form. Mouse select ADODC control - right-click - ADODC properties - use connection string - generated.

2) Select Microsoft OLE DB Provider for Oracle and go next.

3) Fill in the required content according to the data link properties dialog box and test the connection. Point OK, and finally get the connection string on the ADODC property page, copy the string, and you can use it directly as an ADodC data access control, or in ** for an ADodc control or ADO data access object.