>How I can know if a table is in a database and release?
INDBC() will tell you if a table is in the current DBC().
The backlink to a database container is in the header of the file. To find out if a table is in a DBC (and fine which one) you can examine the header with something like
USE myFile SHARED
lcHeader = LEFT(FILETOSTR(DBF()),HEADER())
lcDatabase = RIGHT(lcHeader,263)
If the first character is ASC(0) then the table is not in a DBC