The LA Fox Developer Newsletter

March 1999

Reapplying Default Values to

Recycled Records

Microsoft Knowledge Base Article Qi 68521

In Visual FoxPro, the DELETE command does not delete a

record physically; rather, it only marks the record for deletion.

Using the RECALL command unmarks the deleted record. In

order to physically delete a record from a table in Visual

FoxPro, use the PACK command. Using PACK requires the

table to be opened exclusively. In a multi-user environment, it

may be difficult to obtain exclusive use of the file for packing. To

work around this problem, you can recycle deleted records by

using the technique illustrated below.

This article assumes you have an existing database and certain

fields have default values in the table.

The following code snippet does the following:

Looks for a deleted record.

Retrieves the default values from the table in the database.

Re-uses the first deleted record found.

If no deleted records are found, a new record is appended

LOCAL IcDeleted, dExpr, ncount, a_field(1)

IcDeleted = set(”DELETED”)

SET DELETED OFF

Looks for deleted record in the table

LOCATE FOR DELETED()

IF FOUNDO

*

bring it back to life and blank its fields

RECALL

*

blank out the contain of the deleted record

BLANK

*

Retrieve all default values from the base table.

FOR nCount = I to AFIELDS(a_field)

dExpr = BGetProp(CursorGetProp(”SourceName”)+;

“.“ + a_field[nCount, 1], “Field”,;

“DefaultValue”)

*

if there is a default value, use it

IF not Empty(dExpr)

REPLACE (a_field(nCount, 1]) WITH;

EVAL(dExpr)

ENDIF

ENDFOR

ELSE

APPEND BLANK

ENDIF

SET DELETED &lcDeleted

In order to retrieve default values from the database, the data-

base needs to be open at all times. If the database is not open,

an error occurs.

NOTE:

Unused space in memo files will not be recycled. To

recover unused space in memo files, you must issue a PACK

MEMO command (which requires that the table be opened

EXCLUSIVEly).

[Ed. Note: MS Knowledge Base articles may be reprinted

freely. If you have a favorite or interesting one, forward it along

to me at brlee@mesllc.com.]

Out and About (Con’t from page 3)

membership year when everyone that hasn’t paid their member-

ship fees will stop receiving the newletter. So if you get a call

from one of your fellow members, inquiring about the newsletter,

tell them that all they need to do is to pay their dues and

everything will be alright. <g> You can remind them that

Standard membership is $48 and Premium membership is

$120. Standard membership gets you everything it did in the

past. Premium membership allows you to get the newsletter in

advance (electronically), a ZIP file of all the past newsletter

articles in .DOC format (almost 5 year’s worth. ..as long as I’ve

been the editor). This month also marks the inception of

(Con’t, page 7)

“We get letters” Dept...

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Top 5 Reasons for

C0000005 errors in VFP

From the UT (Universal Thread)

In the Letterman tradition:

Reason #5: MS Alpha-testers were too hung-over from the “We

Made Visual Studio 6!” party to notice it.

Reason #4: A new Fox Team coder is an ex-Ashton/Tate

employee on a suicide mission.

Reason #3: A lousy attempt at what would have been a great

Easter Egg.

Reason #2: Secret MS memo reveals that VFP has to be

stopped!

And, finally....

Reason #1: Because VFP developers needed *something* to

moan about in the new release!

John S. Koziol

MCP - Visual FoxPro