Update simple.py

README.md

@@ -135,6 +135,27 @@ txn.mutate(set_obj=p)
 # txn.mutate(set_nquads='_:alice <name> "Alice"')
 ```
 
+```python
+# Delete data.
+
+query1 = """query all($a: string)
+ {
+   all(func: eq(name, $a)) 
+    {
+      uid
+    }   
+  }"""
+
+variables1 = {'$a': 'Bob'}
+
+res1 = client.query(query1, variables=variables1)
+
+ppl1 = json.loads(res1.json)
+
+#For mutation to delete node, use this: 
+txn.mutate(del_obj= person)
+```
+
 For a more complete example with multiple fields and relationships, look at the
 [simple] project in the `examples` folder.
 

examples/simple/simple.py

@@ -23,6 +23,7 @@ def drop_all(client):
 def set_schema(client):
     schema = """
     name: string @index(exact) .
+    friend: uid @reverse .
     age: int .
     married: bool .
     loc: geo .
@@ -78,11 +79,45 @@ def create_data(client):
         print('All created nodes (map from blank node names to uids):')
         for uid in assigned.uids:
             print('{} => {}'.format(uid, assigned.uids[uid]))
-        print()
     finally:
         # Clean up. Calling this after txn.commit() is a no-op
         # and hence safe.
         txn.discard()
+        print('\n')
+
+
+#Deleting a data
+def delete_data(client):
+    # Create a new transaction.
+    txn = client.txn()
+    try:
+        query1 = """query all($a: string)
+        {
+           all(func: eq(name, $a)) 
+            {
+               uid
+            }   
+        }"""
+        variables1 = {'$a': 'Bob'}
+        res1 = client.query(query1, variables=variables1)
+        ppl1 = json.loads(res1.json)
+        for person in ppl1['all']:
+            print('Query to find Uid for Bob :')
+            print(query1)
+            print('\n')
+            print("Bob's UID : ")
+            print(person)
+            print('\n')
+            print('Bob deleted')
+            print('\n')
+
+
+        assigned = txn.mutate(del_obj= person)
+
+        txn.commit()
+
+    finally:
+        txn.discard()
 
 
 # Query for data.
@@ -112,8 +147,48 @@ def query_data(client):
 
     # Print results.
     print('Number of people named "Alice": {}'.format(len(ppl['all'])))
+    print('\n')
     for person in ppl['all']:
+        print('Query for Alice : \n' +query)
+        print('\n')
+        print('Result :')
+        print(person)
+        print('\n')
+
+#Query to check for deleted node
+def query_data01(client):
+    query01 = """query all($b: string)
+        {   all(func: eq(name, $b)) 
+            {   uid, 
+                name,
+                age
+                friend 
+                { 
+                    uid,
+                    name,
+                    age 
+                }
+                ~friend 
+                { 
+                    uid,
+                    name,
+                    age 
+                }
+            }   
+        }"""
+
+    variables01 = {'$b': 'Bob'}
+    res01 = client.query(query01, variables=variables01)
+    ppl01 = json.loads(res01.json)
+
+    print('Number of people named "Bob": {}'.format(len(ppl01['all'])))
+    print('\n')
+    for person in ppl01['all']:
+        print('Query for Bob :\n' + query01)
+        print('\n')
+        print('Result :')
         print(person)
+        print('\n')
 
 
 def main():
@@ -122,7 +197,11 @@ def main():
     drop_all(client)
     set_schema(client)
     create_data(client)
-    query_data(client)
+    query_data(client) # query for Alice
+    query_data01(client) # query for Bob
+    delete_data(client) # delete Bob
+    query_data(client) # query for Alice
+    query_data01(client) # query for Bob
 
     # Close the client stub.
     client_stub.close()