When the log file is full and the SQL database cannot write the file, you can use either of the following methods:

One method: Clear logs.
1. Open the query analyzer and enter the command
Dump transaction database name with no_log
2. open the Enterprise Manager and right-click the database you want to compress -- all tasks -- shrink database -- shrink file -- Select log file -- select to shrink to xxm In the shrink mode, here we will provide a minimum number of M that can be reduced. Enter this number directly and click OK.

Another method is risky because the log files of SQL Server are not immediately written to the master database file. improper processing may cause data loss.
1: Delete log
Detach Database Enterprise Manager-> server-> database-> right-click-> detach Database
2: delete log files
Attach Database Enterprise Manager-> server-> database-> right-click-> attach Database
This method generates a new log with a size of more than 500 K.

Note: The first method is recommended.

If you do not want it to become larger later.
Use in SQL2000:
Right-click the database and choose Properties> Options> fault recovery> model> select simple model.
Or use an SQL statement:
Alter database name set recovery simple