SQLite Provider / Memo

[porpoise]

I have connected a TDBLookupComboBox to a TUniQuery object connected to an TUniConnection using the SQLite provider. I am attempting to show a field called "Name" of type TEXT as a lookup field in the TDBLookupComboBox, but the lookup field is displayed as "(Memo)" instead of the field's contents. I suspect the TDBLookupComboBox thinks the field is a CLOB since SQLite doesn't differentiate between text and a CLOB ... and hence the "(Memo)" text.

If I use a memory table and have the Name field defined as String, it works as expected.

Any suggestions for a way around this would be appreciated.

I'm using the 2.70.0.9 UniDAC demo with Delphi 2009 Pro.

[porpoise]

I was able to get the following to work to obtain a lookup value:

Code: Select all

SELECT ID, CAST(Name AS VarChar(255)) AS Name
FROM MyTable

By casting the Name field (defined as TEXT in SQLite) as a VarChar in SQL, it will display properly in the TDBLookupComboBox. But this is not ideal ... anyone else have some ideas?

[Plash]

UniDAC always maps TEXT to TMemoField. You need to change data type of the field in the database or use any expression with this field in your SELECT query.

[stevel]

UniDAC always maps TEXT to TMemoField. You need to change data type of the field in the database or use any expression with this field in your SELECT query.

I don't understand what you mean by "change data type of the field in the database" - what can you change to from TEXT?


Regards,
Steve F

[AlexP]

Hello,

As the TEXT field contains text data, you can change the type of this field to, for example, VARCHAR in the following way:

Code: Select all

CREATE  TABLE t1(id integer,txt text);
.....
INSERT INTO t1................
....
CREATE TEMPORARY TABLE t1_backup(id integer,txt varchar(255));
INSERT INTO t1_backup SELECT id,txt FROM t1;
DROP TABLE t1;
CREATE TABLE t1(id integer,txt varchar(255));
INSERT INTO t1 SELECT id,txt FROM t1_backup;
DROP TABLE t1_backup;

[stevel]

After changing field type from TEXT to VARCHAR will it UniDAC start recognizing it as String field (instead of Blob)?

[AlexP]

Hello,

Yes, if you change the field type from Text to VARCHAR, UniDAC will define it as TStringField or TWideStringField (depending on the settings of TUniConnection UseUnicode).

[stevel]

In the SQLite database I had a VARCHAR(255) field, when adding a TUniTable / TUniQuery component and click on 'Add all fields', it added the field as TWideStringField, which is correct.

However, when I increased the length of the field in the database from 255 to 4096, then when creating the fields again in the UniTable / UniQuery components, it creates the field as TMemoField.

Why is this happening and how can this be resolved? I need the fields to be string type and not memo.

[AlexP]

hello,

Thank you for the information.
We have reproduced and fixed the problem.
This fix will be included in the next build.

[stevel]

Since I need to deploy the app to my client urgently, is there any workaround I can use in the meantime to get the WideString field?

[AlexP]

Hello,

If you have UniDAC Edition with Source code, I can send the fix of this problem. Unfortunately, this problem cannot be solved without fixing the source code

[stevel]

Unfortunately I don't have the source code edition of UniDAC. Please state when we can expect the next version to be released.

[AlexP]

Hello,

Please send to alexp*devart*com your license number, IDE version and e-mail address to which I can send you the product with the fix.