Query in Genie + SQLite

Question

I'm practicing with Genie + SQLite and I'm blocked when I try to make a query.

uses Sqlite

init    
    db : Sqlite.Database
    Sqlite.Database.open ("agenda.db3", out db)

    db.exec ("CREATE TABLE Contactos (pkiD INTEGER PRIMARY KEY, nombre TEXT UNIQUE, phone INTEGER)")

    stdout.printf( "Nuevo contacto: " )
    contacto_nombre:string = stdin.read_line()

    stdout.printf( "Teléfono: " )
    contacto_phone:string = stdin.read_line()

    enter:string = @"INSERT INTO Contactos (nombre, phone) VALUES ('$contacto_nombre', $contacto_phone)"

    // if contacto_nombre exists  ????????????
        //"SELECT nombre FROM Contactos WHERE nombre = 'contacto_nombre'"   ????
        //stdout.printf("%s ya está en la Agenda.\n", contacto_nombre)
    //else
        db.exec (enter)

How can I check if a value already exists? Thank you.

Answer 1

Well, I do not know if this is the best way to do it, but I have found this solution.

uses
    Sqlite
    Gee

init    
    db : Sqlite.Database
    Sqlite.Database.open ("agenda.db3", out db)

    db.exec ("CREATE TABLE Contactos (pkiD INTEGER PRIMARY KEY, nombre TEXT UNIQUE, phone INTEGER)")

    stdout.printf( "Nuevo contacto: " )
    contacto_nombre:string = stdin.read_line()

    statement:Statement
    db.prepare_v2("SELECT nombre FROM Contactos", -1, out statement)

    cols:int = statement.column_count ()

    var row = new dict of string, string
    item:int = 1

    var lista = new list of string

    while statement.step() == ROW
        for i:int = 0 to (cols - 1)
            row[ statement.column_name( i ) ] = statement.column_text( i )
            lista.add(row[ "nombre" ])
        item++
    if lista.contains(contacto_nombre) == true
        stdout.printf("%s ya está en la Agenda.\n", contacto_nombre)    
    else
        stdout.printf( "Teléfono: " )
        contacto_phone:string = stdin.read_line()
        enter:string = @"INSERT INTO Contactos (nombre, phone) VALUES ('$contacto_nombre', $contacto_phone)"
        db.exec (enter)