====== PostgreSQL ======

===== Installation =====

Source: [[https://pypi.org/project/psycopg2-binary/]]

Installer **psycopg2-binary** au lieu de **psycopg2** permet d'éviter
d'installer les paquets nécessaires à la compilation de la librairie.

<code bash>
pip3 install psycopg2-binary
</code>

===== Modules à importer =====

<code python>
import psycopg2, psycopg2.extras
</code>

===== Connexion =====

<code python>
try:
    conn = psycopg2.connect(
        user     = username,
        password = password,
        host     = host,
        port     = port,
        database = dbname)
except(Exception, psycopg2.Error) as error:
    conn = None
    print("Erreur: ", error)
</code>

===== Déconnexion =====

<code python>
if conn:
    conn.close()
</code>

===== Requête =====

<code python>
cursor = conn.cursor(cursor_factory = psycopg2.extras.DictCursor)

try:
    cursor.execute("SELECT id, nom FROM table WHERE id = %s;", (5,))
    rows = cursor.fetchall()
    
    # Transformation de liste de DictRow en
    # liste de dictionnaires standards
    result = []
    for row in rows:
        dico = {}
        for key, col in enumerate(cursor.description):
            dico[col[0]] = row[key]
        result.apend(dico)
        
finally:
    cursor.close()
</code>