This tutorial describes how to retrieve data from tables using the TLiteQuery and TLiteTable components.
This walkthrough supposes that you know how to connect to server (tutorials "Connecting To SQLite Database"), how to create necessary objects on the server (tutorial "Creating Database Objects"), and how to insert data to created tables (tutorial "Inserting Data Into Tables").
As we know, an original function of any database application is establishing connection to a data source and working with data contained in it. LiteDAC provides several components that can be used for data retrieving, such as TLiteQuery and TLiteTable. We will discuss data retrieving using these components.
The goal of this tutorial is to retrieve data from a table dept.
The following code demonstrates retrieving of data from the dept table using the TLiteQuery component:
[Delphi]
var
LiteQuery: TLiteQuery;
begin
LiteQuery := TLiteQuery.Create(nil);
try
// LiteConnection is either TLiteConnection already set up
LiteQuery.Connection := LiteConnection;
// retrieve data
LiteQuery.SQL.Text := 'SELECT * FROM dept';
LiteQuery.Open;
// shows the number of records obtained from the server
ShowMessage(IntToStr(LiteQuery.RecordCount));
finally
LiteQuery.Free;
end;
end;
[C++Builder]
{
TLiteQuery* LiteQuery = new TLiteQuery(NULL);
try
{
// LiteConnection is either TLiteConnection already set up
LiteQuery->Connection = LiteConnection;
// retrieve data
LiteQuery->SQL->Text = "SELECT * FROM dept";
LiteQuery->Open();
// shows the number of records obtained from the server
ShowMessage(IntToStr(LiteQuery->RecordCount));
}
__finally
{
LiteQuery->Free();
}
}
The following code demonstrates retrieving of data from the dept table using the TLiteTable component:
[Delphi]
var
LiteTable: TLiteTable;
begin
LiteTable := TLiteTable.Create(nil);
try
// LiteConnection is either TLiteConnection already set up
LiteTable.Connection := LiteConnection;
// retrieve data
LiteTable.TableName := 'dept';
LiteTable.Open;
// shows the number of records obtained from the server
ShowMessage(IntToStr(LiteTable.RecordCount));
finally
LiteTable.Free;
end;
end;
[C++Builder]
{
TLiteTable* LiteTable = new TLiteTable(NULL);
try
{
// LiteConnection is either TLiteConnection already set up
LiteTable->Connection = LiteConnection;
// retrieve data
LiteTable->TableName = "dept";
LiteTable->Open();
// shows the number of records obtained from the server
ShowMessage(IntToStr(LiteTable->RecordCount));
}
__finally
{
LiteTable->Free();
}
}