Get the fieldtypes of a dataset
lazarus / 16-Databases

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Hansvb · 2016-02-20 17:00

How to extract the fieldtypes  of a dataset? I tried this but that
gives an error


Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i mystring :=
Active_DBGrid.DataSource.DataSet.Fields[i].DataType;  //mystring is a
string variable
the error  :
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i
Incompatible types: got "TFieldType" expected "AnsiString"
So how can i convert the Fieldtype to String?

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howardpc · 2016-02-20 18:03

Try this function:

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i uses db,
typinfo; function FieldTypeAsString(aFieldType: TFieldType):
string;begin  Result:=GetEnumName(TypeInfo(TFieldType),
Ord(aFieldType));end;

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itmitica · 2016-02-20 18:44

You don't.

You create a TFieldType variable and then you look the value up in the
TFieldType enumerated set. Above you got the exemplification. Below
there are some explanations about enumerated sets.

http://lazarus-ccr.sourceforge.net/docs/fcl/db/tfieldtype.html

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i uses   db,
// using db adds the TFieldType type to the environment  typinfo; //
using typinfo adds the GetEnumType function to the environment var 
ft: TFieldType;  // you could also declare a set sft: set of
TFieldType;
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i // ft :=
Active_DBGrid.DataSource.DataSet.Fields[i].DataType;ft := ftString;//
sft := [ftUnknown, ftString, ftInteger];
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i // if
Ord(TFieldType.ftUnknown) = 0 // trueif Ord(ft) = 1 //true
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i // if
GetEnumName( TypeInfo(TFieldType), 0 ) = ftUnknown // trueif
GetEnumName( TypeInfo(TFieldType), Ord(ft) ) = ftString // true

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Hansvb · 2016-02-20 20:25

Thanks. I used the solution from Howardpc. It works.

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LacaK · 2016-02-23 17:13

Quote from: Hansvb on February 20, 2016, 06:00:18 pmSo how can i
convert the Fieldtype to String?

There is array FieldTypeNames.

Usage: FieldTypeNames[Fields.DataType]