Create View, Set View, Set
Here's a pair of
commands you should avoid, plus one we use all the time. We can't
figure out why CREATE VIEW and SET VIEW aren't marked "for
backward compatibility only"—they should be. Actually, even in
backward times, views of this sort weren't such a good idea. SET
by itself, though, is handy when you're developing—it opens the
Data Session (formerly known as View) window.CREATE VIEW creates
a "view file" with the extension VUE that contains information
about the current FoxPro environment. SET VIEW reads the
information in a VUE file and re-establishes that environment.
Usage
|
CREATE VIEW ViewFileName
SET VIEW TO ViewFileName | ?
SET VIEW ON | OFF
SET
|
Sounds pretty good, so what's our complaint? First of
all, views have never contained all the information needed to
make them really useful. For example, they include the open
tables and indexes, but not the record pointers for those tables.
To really save the environment, try reduce, reuse, recycle.Second
and far more serious, VUE files (like MEM files) are a mysterious
format. You can't open them up and mess around, except using the
low-level file functions. It makes far more sense to create your
own status table—you can use the various status-tracking
functions to get the information you need and store it all in a
nice, readable format.Don't confuse this CREATE VIEW command with
CREATE SQL VIEW, which lets you define views of remote and local
data. Those views have nothing to do with these views. The Help
file lists all the things that get stored in a view, so we won't
repeat them here. We did find a couple of oddities in SET VIEW's
behavior, which we will share.Although the current default
directory is stored as part of the view, in VFP 3 it wasn't
restored. But the paths to open tables were stored relative to
the default directory. So, if you SET VIEW from a different
directory than you CREATEd it, VFP 3 couldn't open the tables.
VFP 5 and later versions are better behaved in this regard—they
set default to the stored default directory.In the "that's
interesting, but when will I ever use this?" category, Visual
FoxPro's updated View window (now called the Data Session window)
tends to show open tables in reverse work area order. If you use
the View window to open tables or you habitually issue SELECT 0
before USEing a table, you'll normally see the tables in reverse
work area order. When SET VIEW restores the open tables, they
turn up in work area order in the View window. (We don't know
when you'll ever use this piece of information, either.)SET VIEW
ON or OFF is something completely different. It controls the Data
Session window. SET VIEW ON makes it appear, and SET VIEW OFF
makes it disappear. We've never seen any reason to type that many
characters, because using SET, by itself, opens the View window;
pressing ESC while it has focus closes it.
See Also
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AUsed(), Create SQL View, Relation(), Set, Set
Alternate, Set Default,
Set Fields, Set Filter, Set
Format, Set Help, Set Path, Set
Procedure, Set Resource,
Set Skip, Set Status Bar, Used()
|
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Copyright © 2002-2018 by Tamar E. Granor,
Ted Roche, Doug Hennig, and Della Martin. Click for license
.