Want to win a PS4? Go Premium and enter to win our High-Tech Treats giveaway. Enter to Win



Posted on 2008-06-12
Medium Priority
Last Modified: 2013-11-23
Hi Geniuses, Gurus, Experts, et al.,
I want to make sure I understand. There was a question answered before about setting default values when creating a table. It was closed and the expert said there was a M$ bug. Are you saying there is no way to create a column that contains a default value when programming in Delphi and working with an Access 2000 database? I tried the following and it didn't work:

with MyQuery do
    SQL.Add('ALTER TABLE ' + TableName + ' ');
    SQL.Add('ADD COLUMN Deleted CHAR(1) DEFAULT ''N''');

Help please.
Question by:reforest
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
LVL 18

Expert Comment

ID: 21776092
One problem as I see it is you should be using an ADOCommand. Works with Access fine.

Here is an example...

 ADOCommand1.CommandText := 'Alter Table CDLib ADD CDKey Text(50)';
 ADOCommand1.CommandText := 'Alter Table CDLib ADD Comments Memo';

You can then add your default text as you did above.

I also would use quoted string. I feel it makes quoted strings in strings easier and more fool proff.:

SQL.Add('ADD COLUMN Deleted CHAR(1) DEFAULT ' + QuotedStr('N'));

Hope this helped.

LVL 13

Expert Comment

ID: 21777331
"I tried it and it didn't work"
-please provide details as to in what way it did not work, such as any error messages or the results.

Just a minor note about the field "Deleted" - I don't think it's a reserve word but just in case it is you may want to put it in quotes or show it as a descendant of a table
SELECT MyTable.Deleted  FROM MyTable

Expert Comment

ID: 21777353

Try this way :
SQL.Add('ADD COLUMN Deleted CHAR(1) DEFAULT ''N'' with values');
Industry Leaders: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!


Author Comment

ID: 21780335
The following code created the column, but did not put any values into rows that already contained data, and the last row (when viewed in Access) had #Error in the Deleted column:

DataMod.CommandQuery.CommandText := 'ALTER TABLE Chemicals ADD COLUMN Deleted CHAR(1) DEFAULT ' + QuotedStr('N');

The following code caused an error that said 'Syntax error in ALTER TABLE statement':
with MyQuery do
    SQL.Add('ALTER TABLE Chemicals ADD COLUMN Deleted CHAR(1) DEFAULT ''N'' with values');

So, still nothing that adds 'N' to my new column. Thanks for the help, but more ideas needed.
LVL 54

Accepted Solution

nico5038 earned 750 total points
ID: 21786997
I'm afraid that the CREATE TABLE statement of the Jet-engine (the access database engine) doesn't support default values.
When you're able to open the Access Tables collection from Delphi with code, then a default value can be added. I used VBA code in the past to manipulate table field properties, but that's "within" Access and not in the database engine....


Author Closing Comment

ID: 31466820
Thanks for the help. It always stinks when the answer is, 'You can't do it the easy way'. Oh well. I've figured out a workaround now.
LVL 54

Expert Comment

ID: 21807159
Glad I could help, but now I'm curious how your work around is implemented....
I guess you use an UPDATE query or add the Default value to the form field before the INSERT.


Author Comment

ID: 21809846
Actually, it's not anything interesting. I found a way to do what I wanted to do without entering a default value at all. I'm such a beginner that I was having trouble trying to select rows where MyTextField = ''. I thought if I added a default, then I could SELECT * from MyTable WHERE MyTextFIeld = 'Default'. I now know that I need to SELECT * from MyTable WHERE MyTextFIeld Is Null.

BTW, I still have no idea how to rename columns or copy data from one column to another within the same table...want me to submit a new question?
LVL 54

Expert Comment

ID: 21817963
No need for a new question, as I'm not "in for the points" :-)

To copy data from column to column use:

        UPDATE tblA SET fieldA = FieldB

Without a WHERE clause all rows will be effected. (Always try first on a backup copy of the table when manipulating data in tables!)

Renaming is done with the "AS" predicate like:

        SELECT fieldA AS Column1 from tblA

This will give one column named "Column1" in the output of the query.

Success with your application !


Author Comment

ID: 21819115
Thanks for the help, but I'm still having trouble.

Before you sent this reply I opened a question titled 'UPDATE table SET col1 = col2 not working', because I found something on the internet about copying columns in SQL. The question is still open, though, because it's not working in Delphi. It works if I open my Access database and run the UPDATE query, but not when I try to do it in code from Delphi.

I have successfully run other types of queries (SELECT INTO, ALTER TABLE, ALTER COLUMN, etc.), so I know how it works most of the time. It's just not working for my UPDATE query.

Do you program in Delphi?

Featured Post

Free Tool: SSL Checker

Scans your site and returns information about your SSL implementation and certificate. Helpful for debugging and validating your SSL configuration.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Access developers frequently have requirements to interact with Excel (import from or output to) in their applications.  You might be able to accomplish this with the TransferSpreadsheet and OutputTo methods, but in this series of articles I will di…
Did you know that more than 4 billion data records have been recorded as lost or stolen since 2013? It was a staggering number brought to our attention during last week’s ManageEngine webinar, where attendees received a comprehensive look at the ma…
In Microsoft Access, learn different ways of passing a string value within a string argument. Also learn what a “Type Mis-match” error is about.
With Microsoft Access, learn how to specify relationships between tables and set various options on the relationship. Add the tables: Create the relationship: Decide if you’re going to set referential integrity: Decide if you want cascade upda…
Suggested Courses

609 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question