NAME
dbread_view, dbwrite_view, dbsave_view - read, write and save database views
SYNOPSIS
int dbwrite_view ( Dbptr db, FILE *file );
int dbread_view ( FILE *file, Dbptr *dbr, char *name );
int dbsave_view ( Dbptr db );
DESCRIPTION
Dbread_view reads a view from the specified file pointer. If
a name is specified, that name is the name of the new table; otherwise
the new table receives a constructed, unique name.
Dbwrite_view writes a view to the specified file pointer.
Dbsave_view saves a view into the main database directory,
and following the standard naming conventions for the database.
Such a saved view can be referenced as a regular table
later in a different program.
FILES
The new file is created in the same directory as the database,
and is named "database.viewname". I.e., in a database "nrdc", a
new table named "scv" would be saved into a file "nrdc.scv".
RETURN VALUES
Returns 0 on success, otherwise non-zero.
LIBRARY
$(DBLIBS)
DIAGNOSTICS
-
Can't open file to save view
SEE ALSO
dbintro(3)
dbwrite_view(3)
dbread_view(3)
BUGS AND CAVEATS
Dbsave_view will overwrite
any pre-existing file with the chosen name. Thus, if
you name a view "origin", for instance, the real origin table would
be overwritten.
Views are only good so long as their constituent tables are unmodified;
once a table is modified, the view should be recomputed. Dbread_view
checks modification times and will fail to read a view if its
constituent tables have been modified.
AUTHOR
Daniel Quinlan