How to find out if a class exists on an OrientDB using PyOrient?

Question

How is it possible to find out if a class exists; this allowing the prevention of a 'class x already exists in current database' error message?

I have seen the following Question, which gives answers in Java and SQL. I'm looking for the Python equivalent.

Answer 1

I created the following example in pyorient:

MY STRUCTURE:

PyORIENT CODE:

import pyorient

db_name = 'Stack37277880'

print("Connecting to the server...")
client = pyorient.OrientDB("localhost",2424)
session_id = client.connect("root","root")
print("OK - sessionID: ",session_id,"\n")

if client.db_exists( db_name, pyorient.STORAGE_TYPE_PLOCAL ):
    client.db_open(db_name, "root", "root")
    dbClasses = client.command("SELECT name FROM (SELECT expand(classes) FROM metadata:schema)")
    newClass = "MyClass"
    classFound = False
    for idx, val in enumerate(dbClasses):
        if (val.name == newClass):
            classFound = True
            break
    if (classFound != True):
        client.command("CREATE CLASS " + newClass)
        print("Class " + newClass + " correctly created")
    else:
        print("Class " + newClass + " already exists into the DB")

client.db_close() 

First Run Output:

Connecting to the server...
OK - sessionID:  70 

Class MyClass correctly created

OrientDB Studio:

Second Run Output:

Connecting to the server...
OK - sessionID:  74 

Class MyClass already exists into the DB

Hope it helps