CODEWITHSUNDEEP
delphidelphi-xe7design-time
Fabrizio
Fabrizio

Reputation: 8043

Centralizing a TField's Size value

After enlarging a database table's VarChar field from size 20 to size 50, I have to update the Size property of hundreds of design-time created TFields and I would like to do that once for all (I don't want to do the same work again, as soon someone will decide to change the field's size again).

The smartest way that comes to my mind consists in setting the TField's Size property at runtime:

const
  C_MY_FIELD_SIZE = 50;

...

MyField.Size := C_MY_FIELD_SIZE;

The only "problem" is that other programmers will see a misleading value displayed in the Size property of the Object Inspector at design time. I'm wondering if there is an equivalent design-time solution

Upvotes: 1

Views: 352

Answers (1)

Diego Muñoz
Diego Muñoz

Reputation: 201

yes, I use SQL everywhere, not TTables and one of the problems is the max size of Edit boxes. In your case, that size is used for TField size. Well, what I do is at application start, do a query to the database that gets the size of all fields of the tables. In MsSqlServer is:

select table_name, column_name, character_maximum_length 
 from information_schema.columns where data_type='varchar' or data_type='nvarchar' 
 order by TABLE_NAME

that query returns: tableName, field, size in characters for all the fields. With that, build for example an array, or a List to get that info cached in your application.

For example, an array with:

 aLongs[i].sTable:=uppercase(qAux.fields[0].asstring);
 aLongs[i].sField:=uppercase(qAux.fields[1].asstring);
 aLongs[i].iLong:=qAux.fields[2].asinteger;

and then: Function getSize(sMiFieldName:string):integer; that simply search in that array the length for the field. It's necesary to get the info cached because normally that querys retrieving columns size are slows.

Sorry, I can't publish my code completely, thats a resume, I hope you get the idea: Get the sizes in run-time and cache the info in an array, list, collection or whatever.

Upvotes: 1

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