Questions[sqlite]

I'm having a problem that I can't figure out. The situation is as follows: I have a procedure that I call by passing a string, which is basically the name of a table. In this particular case it is "sys_configuration".

That procedure basically executes the following lines:

Query.Close();
Query.ParamByName('TABLA').AsString := Tabla;
Query.Open;

"Query" basically has this:

SELECT * FROM :TABLA;

So you should run the following:

SELECT * FROM sys_configuracion;

TRUE?

Well, apparently I'm having an error. Since when testing it and executing my procedure this happens:

[FireDAC][Phys][SQLite] ERROR: near ":TABLA:" syntax error.

Does SQLite work differently with parameters? I can't find why it fails.

I am using the following code to drop my database tables.

"DROP TABLE IF EXISTS TableName;"

The tables are deleted but I have noticed that the data is still inside the file. That is, after executing this command I would expect my file to have zero bytes, yet the file does not lose a single byte of its size.

Is there a way to delete the table and also all the data in that table?

You will see I need to save the data of a list of items in SQFlite, I am doing it with this procedure

void cargarusuarios() {
      res.forEach((cliente) {
        usuario.usuario = cliente[0].toString();
        usuario.telefono = cliente[1].toString();
        usuario.fechaexpira = cliente[2].toString();
        usuario.email = cliente[3].toString();
        usuario.plan = cliente[4].toString();
        usuario.conexiones = cliente[5].toString();
        DBProvider.db.nuevoUsuario(usuario);
      });
  }

The problem is, the save procedure is executed correctly according to the number of clients, but in all of them only the information corresponding to the last one is saved.

I would think that in each of the steps it would save the information of that iteration and in the following ones it would act in the same way.

Good day everyone, my question is the following, suppose I have the following two tables:

table1 id1
id2 data1 data2
---- ---- ------- -------
1 a d1a1 d2a1
1 b d1b1 d2b1
2 a d1a2 d2a2
2 b d1a2 d2a2
3 a d1a3 d2a3
3 c d1c3 d2c3

table2
id1 id2 data3 data4
---- ---- ------- -------
1 a d3a1 d4a1
null b d3b1 d4b1
null a d3a2 d4a2
2 b d3a2 d4a2

and I want to join them by doing:

SELECT t1.*, t2.* FROM table1 t1 JOIN table2 t2 ON t1.id1 = t2.id2 AND t1.id2 = t2.id2

This will return the following table:

id1 id2 data1 data2 data3 data4
---- ---- ------- ------- -------- --------
1 to d1a1 d2a1 d3a1 d4a1
2b d1b2 d2b2 d3b2 d4b2

What should I do to get the following table as a result:

id1 id2 data1 data2 data3 data4
---- ---- ------- ------- -------- --------
1 to d1a1 d2a1 d3a1 d4a1
null b null null d3b2 d4b2
null a null null d3a2 d4a2
2 b d1b2 d2b2 d3b2 d4b2

Hi, I want to do a delete using SQLite and I would like the query not to be executed if the where field does not exist. Is this possible? Here is an example of my query:

delete from SANCION_DETALLE where SANCION_DETALLE.SANCION = 47

(This query is executed even if there is no sanction 47 in my table)

Thanks in advance.