I have read technical articles about how to connect to and use Access databases in Visual Basic. In fact, in professional database software development, in order to ensure the security of information in the database, encryption is often required for database files to prevent unauthorized users from opening them through other conventional means. In Visual Basic
I have read technical articles about how to connect to and use Access databases in Visual Basic. In fact, in professional database software development, in order to ensure the security of information in the database, encryption is often required for database files to prevent unauthorized users from opening them through other conventional means. In Visual Basic
I have read about how
ConnectionAnd Access
DatabaseIn fact, in professional
DatabaseIn software development, to ensure
DatabaseInformation security, usually requires
DatabaseFiles are encrypted to prevent unauthorized users from opening them through other conventional means. In Visual Basic, how to establish and encrypt
DatabaseOf
ConnectionWhat about it? I have summarized some methods and skills in the development of the dormitory management information system of this school, and now I am writing it out to communicate with colleagues.
1. Establish
Database
Because in Visual Basic 6.0
Database
ConnectionMethod does not support Access 2000 format
DatabaseIn this article
DatabaseUse Access 97
DatabaseFor example.
Create
DatabaseFor example, ssgl. mdb, and set the password, for example, "1234 ".
DatabaseFiles and the project files created in VB are placed in the same directory.
If your computer only has Access 2000, You can first create ssgl. mdb in Access 2000.
DatabaseAnd set the password, and then use"
DatabaseUtility"
DatabaseConvert to the format of Access 97.
Of course, you can also directly create a data manager in the integrated development environment of Visual Basic 6.0.
DatabaseAnd then set the password in Access 97.
Through
DatabaseSet the password for the file. Generally, illegal users cannot open the file by conventional means.
DatabaseYes, right
DatabaseInformation has played a certain role in security and confidentiality.
II,
ConnectionEncrypted Access
Database
In Visual Basic 6.0
DatabaseOf
ConnectionThere are many technical means available, such as data controls, data objects, and data environment designers. Developers can select based on their own conditions and user needs.
The following section only describes encrypted Access.
DatabaseAnd Access without encryption
DatabaseIn
Connection. About unencrypted
DatabaseOf
ConnectionReaders can refer to other materials.
1. Use Controls
① Data Control
The Data control is a built-in Data control in Visual Basic 6.0. You can set the connect, DatabaseName, and RecordSource attributes of the Data Control
DatabaseOf
ConnectionAnd access. Data Control
ConnectionEncrypted
DatabaseThere are two methods:
One way is to change the default value of the connect attribute of the Data Control in the "Properties window" to "Access"; pwd = 1234 "when designing the status, other attributes and unencrypted Access
DatabaseOf
ConnectionSame.
Another method is to assign values to the connect attribute through the code at runtime. For example:
Data1.connect = "; pwd = 1234"
Data1.DatabaseName = APP. path + "ssgl. mdb"
Where "1234" is Access
DatabaseThe password of the ssgl. mdb file.
② Adodc Control
The Adodc control is an ActiveX control that is created from Microsoft ActiveX Data Objects (ADO)
DatabaseOf
Connection. Before using the Adodc control, add the Adodc control to the control toolbox. The method is as follows: in VB 6.0, select the "project" menu, click the "parts" menu item, and select "Microsoft ADO Data Control 6.0 (OLEDB)" in the "parts" dialog box that appears) "option.
Using the Adodc Control
ConnectionEncrypted
DatabaseThere are two methods:
One way is to set a valid ConnectionString attribute for the Adodc control in the "Property Window" during design.
ConnectionString, and
ConnectionAdd "; Jet OLEDB: DataBase password = 1234" to the string, and set the CommandType and RecordSource attributes of the Adodc control to the encrypted
DatabaseOf
Connection.
Another method is to dynamically set the ConnectionString, CommandType, and RecordSource attributes in the code at runtime to create
Connection. As long as the ConnectionString attribute is valid
ConnectionAdd "; Jet OLEDB: DataBase password = 1234" to the string.
2. Use Data Objects
① DAO Data Object
You must properly reference DAO data objects to establish and
DatabaseOf
ConnectionSelect the "project" menu in the VB integrated development environment, and then click the "Reference" menu item, in the "Reference" dialog box that appears, select the "Microsoft DAO 3.51 Object Library" option to add the DAO Data Object Type Library.
Next, you can use the following code to create an encrypted Access
DatabaseSsgl. mdb
Connection.
Dim db AS DataBase
Set db = OpenDataBase (App. path + "ssgl. mdb", False, False, "; pwd = 1234 ")
② ADO Data Object
ADO is a processing relationship launched by Microsoft.
DatabaseNon-relational
DatabaseThe latest information technology is also Microsoft's favorite for Data
ConnectionAnd access technologies. In VB 6.0, Adodc controls, ADO data objects, and DataEnvironment (data environment designer) All use ADO technology, so they process encrypted Access
DatabaseThe method is similar.
To correctly reference ADO Data Objects, select the "project" menu in the integrated development environment of VB 6.0, and then click the "Reference" menu item, in the "Reference" dialog box that appears, select the "Microsoft ActiveX Data Objects 2.1 Library" option to add the ADO Data Object Type Library.
Use the following code to create an encrypted Access
DatabaseSsgl. mdb
Connection.
Dim cnn as adodb. Connection
Dim rst as adodb. Recordset
Set cnn = New ADODB. Connection
Cnn. Provider = "Microsoft. Jet. OLEDB.3.51"
Cnn. ConnectionString = "Data Source =" & App. path & "ssgl. mdb ;"&_
"; Jet OLEDB: Database password = 1234"
Cnn. Open
③ Use DataEnvironment (data environment designer)
There are two ways to use DataEnvironment
ConnectionTo encrypted Access
Database:
One way is to design the status when the ConnectionSource attribute of the connection object of DataEnvironment is valid
ConnectionAdd ";
Jet OLEDB: Database password = 1234"
Another method is to write the following code in the DataEnvironment_Initialize () event:
Private sub DataEnvironment_Initialize ()
Dim strconn AS string
Strconn = "Provider = Microsoft. Jet. OLEDB.3.51 ;"&_
"Data Source =" & App. path & "ssgl. mdb ;"&_
"; Jet OLEDB: Database password = 1234"
DataEnvironment1.connection1. connectionstring = strconn
End sub
The above methods and related code have been debugged, verified and passed in the Windows 98 operating system environment and Visual Basic 6.0.
