pdx 10,win98/is there a limit of how-many-255-char.-fields?

[visitingbizowner]

Hello, all,
First, thank you ahead of time for any help . I've searched the archives for some of this info, and found some useful items, but am hoping for a specific answer.

Am using Pdx 10 on windows 98, trying to re-design a database from years ago in pdx dos,then earlier win versions. No need to deal with the earlier data just yet; have built a table from scratch in vers. 10. I understand the 255-character limit in the fields, but is there a limit to the *number* of 255-max. character fields that can be in one table? I only have under 5,000 records, but I need at least 8 fields of 255-char. each for each record, plus additional fields of around 100 characters. I realize there is an overall mb-size limit to a table (128? or 256 mb?) but will not reach that for years, if ever. These are not permanent records in a database, they will be deleted routinely and new ones added.

If there IS a limit to number of overall fields, I have already started experimenting with creating 2 tables (each with 4 or 5 255-character fields, plus add'tl fields), with an Item Number as keyfield. The problem there is that I want to create one form for our data-entry people that will then dump (1/2) the data into Table A (with some of the 255-char. descriptive fields), and 1/2 the data into Table B (with the rest of the 255-char. descriptive fields). I run into several problems with the form design/run (i.e., one table or the other as I enter test-data says 'this table is read only') or, table look-up out of range (for the Item Number field, which links the 2 descriptive Tables A & B)... etc etc. Perhaps suggestions along these lines from the Programmers and members might point me in the right direction here.

I was a fan/user of Paradox years ago, when I initially set up the business db, but have been out of the loop with it until the acquisition of Vers. 10 a few weeks ago; would love to sort out this db / entry form problem for my part-time data-entry people. I promise to help anyone else down the road, if I can -- Pay-It-Forward, paradox or in other ways Let me know if more specific info, etc. is needed. Thanks.

 

[footpad]

VisitingBizOwner,

There are a couple of limits you may be running into. Paradox tables are limited to 255 fields and there's a limit to the maximum number of characters in the overall structure. Since you only have eight fields, you're clearly not running into that one.

However, you are running into a second limit, one that limits the total number of characters required to express the table. Unkeyed tables are limited to 4000 total characters and keyed tables (which I suspect you're using) are limited to 1350 characters.

Since you're creating multiple A255 fields, it's pretty to do the math. 8 * 255 = 2000.

You either need to reduce that below 1350 or find an alternate way of doing things. For example, you might consider using Memo fields instead. While they can hold lots of text (up to a total size of 64MB per field), the only part that contributes to the record character limit is the size you specify in the restructure dialog (e.g. an M32 field contributes a total of 42 characters to the structure character limit (32 + 10 bytes of overhead).

Now, you can use multiple tables, if you like, however, you'll want to:

a) make sure they're both keyed on a unique field (or set of fields)

b) create a new form and add both tables to the data model.

c) link the tables by dragging the name of the common field(s) from the master table to the detail.

When you do that, you should be able to modify both tables and have the data stay current.

You'll also link the same tables together when designing a report.

Hope this helps...

-- Lance

 

[Guest_imported]

To overcome the message "Table is read-only", go to the data model, right click the child tables and uncheck the table's read-only property.