Using Python to manipulate and manage Arangodb

Directory:

• Connecting to a database
• Create a database/collection/document
• Search Filter
• Update
• Delete
• Methods for calling the AQL

Install the Python package that you need to use:

Pip Install Pyarango

First, connect the database:

>>> from pyarango.connection import *>>> conn = connection (username="root" , password="root_passwd")

When the code executes, it initializes conn the server connection on the variable. By default, Pyarango attempts to establish a connection to http://127.0.0.1:8529.

ii. Creating databases/collections/DocumentsCreate and open a databaseMethod:

CreateDatabase ()

The method can open or create a database on the server, and Pyarango creates it on the server when the database to which it is connected does not exist. When it is present, Pyarango tries to open the database.

>>> db = Conn.createdatabase (name="school")

You can also open an existing database by using its name as a key on the server connection:

>>> db = conn["school"]>>> dbarangodb database:school 

Create a collectionMethod:

CreateCollection ()

>>> studentscollection = db.createcollection (name="Students")> >> db["Students"ID202, type:document, status Loaded

Create a documentMethod:

CreateDocument()

>>> Doc1 =studentscollection.createdocument ()>>> doc1["name"] ="John Smith">>>Doc1arangodoc'None': {'name':'John Smith'}>>> doc2 =studentscollection.createdocument ()>>> doc2["FirstName"] ="Emily">>> doc2["LastName"] ="Bronte">>>Doc2arangodoc'None': {'FirstName':'Emily','LastName':'Bronte'}

Because it has not been saved to Arangodb, the document shows it _id as "None". This means that the variable exists in your Python code, but does not exist in the database. Arangodb constructs a value by pairing the collection name with the __key value _id .

To Save the document:

" JohnSmith ">>> doc1.save ()>>>'students/johnsmith' : {'name''John Smith'}

Loop input data:

>>> students = [('Oscar','Wilde',3.5), ('Thomas','Hobbes',3.2), ... ('Mark','Twain',3.0), ('Kate','Chopin',3.8), ('Fyodor','Dostoevsky',3.1), ... ('Jane','Austen',3.4), ('Mary','Wollstonecraft',3.7), ('Percy','Shelley',3.5), ... ('William','Faulkner',3.8), ('Charlotte','Bronte',3.0)]>>> for(First, Last, GPA)inchStudents: ... doc=studentscollection.createdocument () ... doc['name'] ="%s%s"% (First, Last) ... doc['GPA'] =GPA ... doc[' Year'] = .. .. doc._key="'.Join([First, Last]). Lower () ... doc.save ()

Iii. Search and filterto view the GPA of a particular student:

>>>def Report_gpa (document): ... print ("Student:%s"% document['name']) ... print ("GPA:%s"% document['GPA'])>>> Kate = studentscollection['Katechopin']>>>Report_gpa (Kate) student:kate Chopingpa:3.8

screening students with average scores above 3.5:Method:

Fetchall ()

>>>def top_scores (col, GPA): ... print ("Top soring Students:")...     forStudentinchCol.fetchall (): ...ifstudent['GPA'] >=GPA: ... print ("-%s"% student['name'])>>> Top_scores (Studentscollection,3.5) Top scoring Students:-Mary Wollstonecraft-Kate Chopin-Percy Shelly-William Faulkner-Oscar Wilde

iv. Update

You can define a specific function to handle the update:

>>> def update_gpa (Key, New_gpa): ...     = Studentscollection[key] ...    doc['gpa'= New_gpa ...    Doc.save ()

v. DeleteMethod:

Delete ()

>>> Tom = studentscollection["Thomashobbes"]>>>Tom.delete ()>>> studentscollection["Thomashobbes"]keyerror: ('unable to find document with _key:thomashobbes', {      'Code':404,      'ErrorNum':1202,      'errormessage':'document Students/thomashobbes not found',      'Error': True})

Vi. methods for calling the AQL

In addition to the Python method shown above, ARANGODB provides a query language called AQL, which is used to retrieve and modify documents on the database. In Pyarango, you can use AQLQuery() methods to execute these queries.

Retrieve _key for all documents:

" For x in Students RETURN x._key ">>> queryresult = db. Aqlquery (AQL, rawresults=true, batchsize=) for in queryresult:    ... Print (key) Marywollstonecraftkatechopinpercyshelleyfyodordostoevskymarktwain ...

References:

https://www.arangodb.com/tutorials/cn-tutorial-python/

Using Python to manipulate and manage Arangodb