Delphi tutorial connect SQLite with ZEOS library

For this app to create you will need "sqlite3.dll" file which you can download from : https://sqlite.org/




Just save it in the same folder where your exe file will be, and link to it in you application like I explained in video tutorial.


The third thing you need is installed ZeosDBO components for Delphi, from ZeosLib Development Group, and the lates source code you can find at http://www.sourceforge.net/projects/zeoslib
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Basically that are tools that you need.
We start with creating new project , adding necesary components on the form and writting code to achieve what we want.
In the video you can see all these steps, and in the code for showed example you can see details.

(code style formatted by http://hilite.me/ )

unit MainForm;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls, Grids, DBGrids, DB, ZAbstractRODataset, ZAbstractDataset,
ZDataset, ZAbstractConnection, ZConnection;

type
TfrmMain = class(TForm)
ZConn: TZConnection;
ZQuery1: TZQuery;
ZQuery2: TZQuery;
DataSource1: TDataSource;
DBGrid1: TDBGrid;
Button1: TButton;
Button2: TButton;
ComboBox1: TComboBox;
Label1: TLabel;
Label2: TLabel;
Label3: TLabel;
Edit1: TEdit;
Label4: TLabel;
Edit2: TEdit;
Button3: TButton;
Label5: TLabel;
Edit3: TEdit;
Label6: TLabel;
Edit4: TEdit;
Button4: TButton;
Button5: TButton;
Label7: TLabel;
Label8: TLabel;
procedure Button1Click(Sender: TObject);
procedure Button2Click(Sender: TObject);
procedure ComboBox1Change(Sender: TObject);
procedure Button3Click(Sender: TObject);
procedure Button4Click(Sender: TObject);
procedure Button5Click(Sender: TObject);
procedure DBGrid1CellClick(Column: TColumn);
private
{ Private declarations }
public
{ Public declarations }
end;

var
frmMain: TfrmMain;

implementation

{$R *.dfm}


procedure TfrmMain.Button1Click(Sender: TObject);
begin
ZConn.Protocol:='sqlite-3';
ZConn.LibraryLocation:=ExtractFilePath(Application.ExeName)+'sqlite3.dll';
if not FileExists(ZConn.LibraryLocation) then Exit;
ZConn.Database:=ExtractFilePath(Application.ExeName)+'testdb.s3db';
//if not FileExists(ZConn.Database) then Exit;
ZConn.Connect;
Label2.Caption:='testdb.s3db';
ComboBox1.Items.Clear;
ZConn.GetTableNames('',ComboBox1.Items);
ComboBox1.ItemIndex:=0;
ComboBox1.OnChange(Self);
end;

procedure TfrmMain.Button2Click(Sender: TObject);
begin
ZQuery1.Close;
ZQuery1.SQL.Clear;
ZQuery1.SQL.Add('CREATE TABLE if not exists testtbl(id INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL,'
+'name VARCHAR(255),surname VARCHAR(255), UNIQUE(id))') ;
ZQuery1.ExecSQL;

ComboBox1.Items.Clear;
ZConn.GetTableNames('',ComboBox1.Items);
ComboBox1.ItemIndex:=0;
ComboBox1.OnChange(Self);
end;

procedure TfrmMain.Button3Click(Sender: TObject);
begin
if Edit1.Text<>'' then
begin
ZQuery1.SQL.Clear;
ZQuery1.SQL.Add('Insert into testtbl(name,surname) values('+QuotedStr(Edit1.Text)+','+QuotedStr(Edit2.Text)+')');
ZQuery1.ExecSQL;
ComboBox1.OnChange(Self);
end;
end;

procedure TfrmMain.Button4Click(Sender: TObject);
begin
ZQuery1.SQL.Clear;
ZQuery1.SQL.Add('Update testtbl set name='+QuotedStr(Edit3.Text)+',surname='+QuotedStr(Edit4.Text)
+' where id='+QuotedStr(Label8.Caption));
ZQuery1.ExecSQL;
ComboBox1.OnChange(Self);
end;

procedure TfrmMain.Button5Click(Sender: TObject);
begin
ZQuery2.Delete;
end;

procedure TfrmMain.ComboBox1Change(Sender: TObject);
var i :Integer;
begin
ZQuery2.Close;
ZQuery2.SQL.Clear;
ZQuery2.SQL.Add('Select * from '+ComboBox1.Text);
ZQuery2.Open;

for I := 0 to DBGrid1.Columns.Count-1 do
begin
DBGrid1.Columns[i].Width:=100;
end;
end;

procedure TfrmMain.DBGrid1CellClick(Column: TColumn);
begin
Edit3.Text:=ZQuery2.FieldByName('name').AsString;
Edit4.Text:=ZQuery2.FieldByName('surname').AsString;
label8.Caption:=ZQuery2.FieldByName('id').AsString;
end;

end.