Mixed fields with SQLite

[Juergen Bauer]

Hello,
I have a SQLite database which contains unicode (NVARCHAR, NTEXT) and non-unicode (VARCHAR, TEXT) fields.
Now I would like to access these fields as TStringField or TWideStringField - as required.
How can I archieve this?

When I set UseUnicode to True, all the fields are treated as UniCode fields.
When I set UseUnicode to False, all the fields are treated as non unicode fields.

Thanks for your support.

Bye,
Jürgen

[MaximG]

That's true, the described behavior will be defined by the value of the UseUnicode property. However, you can change it for each field you are interested in separately using DataTypeMapping: https://www.devart.com/unidac/docs/data ... apping.htm

For example:

Code: Select all

           uses  LiteDataTypeMapUni;
           ...
           UniQuery.DataTypeMap.AddFieldNameRule('VARCHARFIELD', ftString, 1024);

           UniQuery.DataTypeMap.AddFieldNameRule('NVARCHARFIELD', ftWideString, 1024);
           

[Juergen Bauer]

With this mappings, I have to define the field size too. Which is not useable.

Why do not map NVARCHAR fields -> ftWideString
and VARCHAR field-> ftString
as defined in the database?

[MaximG]

When adding the DataTypeMapping rule, you do not need to explicitly set the field size value. In this case, the size of the created test field will be determined by the value specified in the DB when it is created. For example, for the TESTTABLE table (

Code: Select all

CREATE TABLE TESTTABLE (NAME VARCHAR(38)) 

), you can specify the following rule:

Code: Select all

UniQuery.DataTypeMap.AddFieldNameRule('NAME', ftString);

In this case, the size of the created field of ftString type will equal 38