What is the use of the. LDB file?

. LDB files are automatically created and deleted by users of the shared database .. The LDB file creates and stores the computer name, user name, and the extended domain lock .. LDB files have the same name as. mdb files and are in the same directory as. mdb files. LDB files are created and locked when they are opened. mdb files. For example, if you open the c: \ northwind. MDB file, the c: \ northwind. LDB file is automatically created and locked.

When the last user closes the shared database, the. LDB file is automatically deleted. However, when the user does not close the database normally or the database has been marked as damaged, the. LDB file will not be automatically deleted because the. LDB File Stores damaged databases and who is using the database.

Permission issues:
Remember to grant certain permissions to the folder where the. LDB file is located.
If you want to share a database, the. MDB file should be placed in a directory with the read, write, create, and delete permissions of the user. Even if you require each user to have different file permissions (for example, read-only or read/write permissions), all users that can share the data should have read, write, and create permissions for the directory, however, you can assign a user. MDB files only have read-only permissions.

Note: If you open a database in an exclusive manner, the MS Jet DB will not create a. LDB file, at this time the user's permission on the directory as long as there are two permissions to read and write.

Content of the. LDB file:
The MS Jet DB Engine creates an entry in the. LDB file for each user who opens the database in a shared manner, with each entry in 64 bytes. The computer name is saved in the first 32 bytes, and the user name is saved in the last 32 bytes. The maximum number of users supported by the Jet DB Engine is 255, so the size of the. LDB file will not exceed 16 kb.
When a user closes a shared database, the user's entries in the. LDB file will not be deleted immediately, but the entry will be overwritten when the next user opens the database. This means that you cannot use the. LDB file to uniquely identify who is the current user of a database.

How to use the. LDB file:
The Jet DB Engine uses the information in the. LDB file to determine who has locked the data and who is writing the data that has been locked by others. If the Jet DB Engine finds a lock conflict with another user, it will read the. LDB file to get the computer name and user name who have locked the file or record.

In most cases, you will receive a "Write conflict" prompt when storing records and cancel your modifications. In some cases, you will receive the following prompt:

Couldn't lock table <Table Name>; currently in use by user <Security Name> on computer <computer name>.

Note: The above information about the. LDB file is irrelevant to the database file. If a. LDB file is corrupted, the database file still works properly. However, you may see a string of yunyun text in the <Security Name> part of the prompt message for writing a conflict.

Refer:
In Access 2000, you can use VBA to output information of all login users of a database.

About thisCodeSee:
198755 acc2000: checking who logged into database with jet userroster
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Original address: http://support.microsoft.com/default.aspx? Kbid = 208778