delphi怎样连接Sqlite 增删改查

delphi连接Sqlite 增删改查例子
数据库已经连通了, 插入会报错，no query specified
with dm.ASQLite3Query1 do
   begin
     dm.ASQLite3Query1.Close;
     dm.ASQLite3Query1.SQL.Clear;   
sqlstr:='insert into student_test(id,username,telephone,address,state) values(:id,:username,:telephone,:address,:state)';                                                  dm.ASQLite3Query1id.Value:=Trim(id_edit.Text); 
  dm.ASQLite3Query1username.Value:=Trim(username_edit.Text); 
  dm.ASQLite3Query1telephone.Value:=Trim(phone_edit.Text); 
  dm.ASQLite3Query1address.Value:=Trim(address_edit.Text); 
  dm.ASQLite3Query1state.Value:=Trim(state_edit.Text); 
  dm.ASQLite3Query1.ExecSQL; 
  dm.ASQLite3Query1.Close; 
  dm.ASQLite3Query1.SQL.Clear; 
  dm.ASQLite3Query1.SQL.Text:='select * from student_test';    
  dm.ASQLite3Query1.Open; 
end;