And I've always got errors, the one I am reporting is:
# apt-get install postgresql-11 pgadmin4
Leyendo lista de paquetes... Hecho
Creando árbol de dependencias
Leyendo la información de estado... Hecho
Package pgadmin4 is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source
E: Package 'pgadmin4' has no installation candidate
I also tried with a virtualenv pgadmin4 and it wasn't possible.
I also hace another computer with a debian sid and I could install postgresql and pgadmin4, buy not in jessie.
Also in jessie didn't work the pgadmin III. Always send messages about when trying server connection.
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Saludos cordiales, Reyna Melara.