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mronck
02-14-2008, 08:04 AM
Suppose you would like to change the database backend from the Alpha dbf into MSSQL.

Would it be an advisable route to:

Export the Alpha tables using the new AlphaDAO Export Genie
Create active link tables from the resulting SQL tables
Rewrite the frontend using Alpha on the active link tables by
Copying the forms etc from the old to the active link tables where possible?


Considering ofcourse that you would not actually loose the *.dbf tables because the active link tables in itself are *.dbf tables, but linking to the source now actually being available in the SQL backend gives advantages.

Is there any experience with indexproblems arising in active link tables and how that would effect the handshake with the linked SQL tables ?

Kind regards,

Marcel Onck

** I don't know how you all see it, but to my opinion V9 looks like a major breakthrough for us developers !

Selwyn Rabins
02-15-2008, 08:38 PM
Suppose you would like to change the database backend from the Alpha dbf into MSSQL.

Would it be an advisable route to:

Export the Alpha tables using the new AlphaDAO Export Genie
Create active link tables from the resulting SQL tables
Rewrite the frontend using Alpha on the active link tables by
Copying the forms etc from the old to the active link tables where possible?


Considering ofcourse that you would not actually loose the *.dbf tables because the active link tables in itself are *.dbf tables, but linking to the source now actually being available in the SQL backend gives advantages.

Is there any experience with indexproblems arising in active link tables and how that would effect the handshake with the linked SQL tables ?

Kind regards,

Marcel Onck

** I don't know how you all see it, but to my opinion V9 looks like a major breakthrough for us developers !
At some point we plan to implement an 'upsize' genie.
But in the mean time.

1. make a backup of your database. IMPORTANT!!!
2. export all tables to your sql backend.
before you do this you will need to do some clean up.
for example, a) alpha five supports multiple auto-increment fields per table. in general, sql databases only support a single auto-increment field per table.
b) alpha five supports auto-increment on non numeric fields. most sql databases don't.
so you will need to fix these issues in your .dbf tables before exporting them.

3. after you have exported, create active link tables on all of the tables you exported.

4. copy the reports, forms, operations, etc. from the dbf tables to the active-link tables.

Selwyn Rabins
02-15-2008, 08:42 PM
Suppose you would like to change the database .

Is there any experience with indexproblems arising in active link tables and how that would effect the handshake with the linked SQL tables ?

** I don't know how you all see it, but to my opinion V9 looks like a major breakthrough for us developers !


There cannot be indexing problems with active-link tables because A5 is not maintaining any indexes for active-link tables. The database server is doing all of the work, including the indexing.

The stability of an application built using active-link tables is a function of the stability of the database server, not alpha five.

Sure would like to see some of the forum members seconding your opinion (which I share, by the way) that V9 is a major breakthrough :)

Kevin Tucker
02-16-2008, 04:02 PM
I am working on testing moving several large DBF tables to SQL and then redesigning some forms to test the functionallity with. Is there any recommendation as to creating sets with active-link tables? Or should you take a different approach when using active link tables? Looking for some recommendations. I tested a piece of our application already using sets and Alpha locked up on the save with no field rules or anything. Still trying to make sure that I did not do something strange.

So far this is awesome. Going to also try moving some of our reports over as well.

Selwyn Rabins
02-16-2008, 08:58 PM
I am working on testing moving several large DBF tables to SQL and then redesigning some forms to test the functionallity with. Is there any recommendation as to creating sets with active-link tables? Or should you take a different approach when using active link tables? Looking for some recommendations. I tested a piece of our application already using sets and Alpha locked up on the save with no field rules or anything. Still trying to make sure that I did not do something strange.

So far this is awesome. Going to also try moving some of our reports over as well.


My main recomendation is to try to keep things simple. We see users send us applications with sets with 20 or 30 tables in them. That's bad design and while you may be able to get away with it in the dbf world where data is local and opening a table is generally very quick, a set that joined 20 or 30 tables will not give you the type of performance that you would want.

mronck
02-21-2008, 07:51 AM
Selwyn, how would Alpha and SQL on exporting treat the Alpha Memo field format? What would become of that in SQL?

Regards,
Marcel

Selwyn Rabins
02-21-2008, 09:48 AM
Selwyn, how would Alpha and SQL on exporting treat the Alpha Memo field format? What would become of that in SQL?

Regards,
Marcel


exporting memo fields is no problem. when a5 exports, it will create the appropriate field type in the backend table to accomodate all of the data in the memo field.

remember that RTF memos are binary data so exporting these to a sql backend does not make that much sense if you plan on using the data in othe programs. on the other hand, if you plan on using the data in a5, then even RTF is ok. just remember that after you have exported the data to sql, when you build your active link table definition, you need to override the field definition for the RTF memo field and set its local type to RTF MEMO.
(that's because when a5 asks the sql backend what the type is of this field, it will report back that it is a binary field - it has no idea that it is RTF data).

mmaisterrena
03-10-2008, 02:54 AM
At some point we plan to implement an 'upsize' genie.
I would love to see that come true

martinwcole
03-10-2008, 11:35 AM
what about HTML Memo fields. are they more generally recognized by sql?

I haven't tried yet, but I think there is the possibility of changing an RTF Memo to HTML Memo.

mmaisterrena
03-10-2008, 03:55 PM
based on what Selwyn stated i suppose that they would be recognized as html if you made an active link to that table and assign that field to be a html memo field inside alpha. but it wont be recognized as beeing an html memo field by any other database

Selwyn Rabins
03-10-2008, 07:04 PM
based on what Selwyn stated i suppose that they would be recognized as html if you made an active link to that table and assign that field to be a html memo field inside alpha. but it wont be recognized as beeing an html memo field by any other database

you are exactly right.
html is just text.
so in an active link table if you did not specifically set the local field type in the active link table to html memo, then you would see the raw html in the field.