Understanding Mysql 'on duplicate key'

$update = "insert into mapa_etiquetas (nombre,urlimagen,id_usuario) values('$this->nombre', '$ruta', '$u') on duplicate key update urlimagen=valu开发者_如何转开发es('$ruta')";

I want to avoid what i do tipically

• SELECT if exists
• If exists
  • Update
• Else
  • Insert

Questions, will the sentence i wrote do that? The way i see it, if i call

$update = "insert into mapa_etiquetas ('casa','image.png',2) 
                      values('$this->nombre', '$ruta', '$u') 
           on duplicate key update urlimagen=values('$ruta')";
$update = "insert into mapa_etiquetas ('casa','image2.png',2) 
                       values('$this->nombre', '$ruta', '$u') 
           on duplicate key update urlimagen=values('$ruta')";

Result will be two elements in table with 'casa' name, right? (instead of editing urlimagen. becaus it will be considred different elements, right)

how could i do to, by one mysql sentence, update urlimagen (for nombre,iduser combination) and if no exists, insert it?

Thanks in advance!

the update urlimagen = values('$ruta') is telling MySql to look for a column named the value of $ruta. Change your statement to use the actual column name:

insert into mapa_etiquetas (nombre, urlimagen, id_usuario)
  values ('$this->nombre', '$ruta', '$u'),
    ('$this->nombre', '$ruta2', '$u')
    /*Add more rows here*/
  on duplicate key update
    urlimagen = values(urlimagen)

Your first query doesn't match your second code block.

First

$update = "insert into mapa_etiquetas (nombre,urlimagen,id_usuario)
    values('$this->nombre', '$ruta', '$u') 
    on duplicate key update urlimagen=values('$ruta')";

Second:Incorrect

$update = "insert into mapa_etiquetas ('casa','image.png',2) 
                  values('$this->nombre', '$ruta', '$u') 
       on duplicate key update urlimagen=values('$ruta')";
$update = "insert into mapa_etiquetas ('casa','image2.png',2) 
                   values('$this->nombre', '$ruta', '$u') 
       on duplicate key update urlimagen=values('$ruta')";

The problem with your second block is that you are naming values where the column names should go. I believe the correct second block should be:

Second:Corrected

$update = "insert into mapa_etiquetas (nombre,urlimagen,id_usuario) 
                  values('$this->nombre', '$ruta', '$u') 
       on duplicate key update urlimagen=values('$ruta')";
$update = "insert into mapa_etiquetas (nombre,urlimagen,id_usuario) 
                   values('$this->nombre', '$ruta', '$u') 
       on duplicate key update urlimagen=values('$ruta')";

I also agree with @The Scrum Meister. Their answer should be heeded regarding appropriate use of the 'on duplicate key update' clause.