About ODBC Data sources

For ODBC data sources (ODBC Data Sources: Data and information to be accessed in programs or databases that support open database connectivity (ODBC) protocol .) (Such as databases and their servers), you can use open database connection (Open Database Connection (ODBC): a standard method for sharing data between databases and programs. The ODBC driver uses the standard Structured Query Language (SQL) to obtain access to external data .) (ODBC) driver for access.

Data Source Definition

The data source is the data source and the connection information required to access the data. Data source examples include Microsoft Access, Microsoft SQL Server, Oracle RDBMS, workbooks, and text files. Examples of connection information include server location, database name, Login ID, password, and various ODBC driver options that describe how to connect to the data source.

In an ODBC architecture, an application (such as access or Microsoft Visual Basic) connects to the ODBC driver manager ", the manager uses a specific ODBC driver (such as Microsoft SQL odbc driver) to connect to the data source (in this case, it is a Microsoft SQL Server database (SQL database: structured Query Language (SQL)-based database .)). In access, ODBC data sources are used to connect to access external data sources without built-in drivers.

To connect to these data sources, you must perform the following operations:

Install the appropriate ODBC driver on the computer that contains the data source.
Define the data source name (DSN): You can use the ODBC data source Manager to store the connection information to the Microsoft Windows registry or DSN File, or use the connection string in the Visual Basic code, directly pass the connection information to the ODBC driver manager ".
Computer Data Source

The computer data source saves the connection information with the name specified by the user in the Windows registry of the specified computer. The data source can only be used on a computer that defines a computer data source. There are two types of computer data sources: User Type and system type. The user data source can only be used by the current user and is only visible to this user. System data sources can be used by all users on the computer, and are visible to all users on the computer and services within the system scope (such as Microsoft Windows Services. The computer data source helps ensure that only logged-on users can view the computer data source and remote users cannot copy it to other computers. Therefore, the computer data source is particularly useful for providing enhanced security performance.

File data source

The file data source (also known as the DSN File) saves the connection information in a text file, instead of in the Windows registry. Generally, file data sources are more flexible than computer data sources. For example, you can copy a file data source to any computer with the correct ODBC driver. Therefore, applications can have consistent and accurate connection information for all these computers. You can also place the file data source on a single server, share the data between multiple computers on the network, and conveniently maintain the connection information in one location.

File data sources can also be non-shared. Non-shared file data sources reside on a single computer and point to a computer data source. You can use a non-shared file data source to access the existing computer data source from the file data source.

Connection string

As a programmer, you can define a connection string in a specific format in Microsoft Visual Basic code to specify the connection information. Using a connection string can avoid defining a computer or a file DSN and pass the connection information directly to the ODBC driver manager ". This is useful. For example, if you do not want a system administrator or user to create a DSN first, or want to simplify the application installation process, you can consider using a connection string. To maintain the security of the connection string information in the code, you can use the MDE file or password to protect the code security.

Security considerations use a strong password that contains both upper and lower case letters, numbers, and symbols. Weak passwords do not mix these elements. For example, Strong Password: y6dh! Et5. Weak Password: house27. Use a strong password that can be remembered, so that you do not need to record the password.