Getting Started With TinyDB

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    Introduction

    While working on your personal projects, you'll often need to store some data. You could use a SQL or NoSQL database with a server, but that would require you to do a bit of setup.

    In this article, we'll learn about TinyDB and how to use it to store our data in JSON format.

    What is TinyDB?

    TinyDB is a document-oriented database written in pure Python with no external dependencies.

    It is designed to be easy and fun to use by providing a simple and clean API. It is quite straightforward to learn and set up, even for a beginner.

    When not to use TinyDB

    As mentioned in the TinyDB docs itself, it is not always the right choice for your projects. If you need advanced features like:

    • access from multiple processes or threads,
    • creating indexes for tables,
    • an HTTP server,
    • managing relationships between tables or similar,
    • ACID guarantees.

    TinyDB is the wrong database for you. In those cases, consider using databases like SQLite, Buzhug, CodernityDB or MongoDB.

    How to Install TinyDB

    It is extremely easy to install TinyDB. Just run this command in your terminal:

    pip install tinydb
    

    How to Use TinyDB

    Consider an example of a Todo Application where we just need to perform CRUD operations. Now that we have TinyDB installed, let's see how we can store our data using TinyDB. TinyDB does everything using JSON.

    The very first thing we'll do is to import the required classes from the tinydb module. So, fire up your Python shell to code along.

    Python 3.9.7 (tags/v3.9.7:1016ef3, Aug 30 2021, 20:19:38) [MSC v.1929 64 bit (AMD64)] on win32
    Type "help", "copyright", "credits" or "license" for more information.
    >>>

    Now we are ready to code.

    >>> from tinydb import TinyDB       
    >>> db = TinyDB("todo_db.json")
    >>>
    

    We have created an instance of the TinyDB class and passed the filename to it. This will create a JSON file todo_app.json where our data will be stored.

    How to Insert Data in TinyDB

    As we are dealing with JSON, the data to be added will be nothing but a Python Dictionary. So, let's see how we can insert an item:

    >>> new_item = {"name": "Book", "quantity": 5}
    >>> db.insert(new_item)
    1
    >>>
    

    First of all, we created a new dictionary called new_item with name and quantity set to Book and 5, respectively. Then we used the insert() method in the TinyDB class to insert the data into the database. The insert() method returns the id of the newly created object.

    At this stage, a new JSON file called todo_db.json will be created and after the data is inserted. It will look like this:

    {"_default": {"1": {"name": "Book", "quantity": 5}}}
    

    If you take a closer look, _default is the name of the table (set by default but can be changed), 1 is the id of the newly created object, and its value is the data we just inserted. So, basically, it is just a nested dictionary.

    We can also insert multiple items at a time like this:

    >>> items = [{"name": "Cake", "quantity": 1},{"name": "Candles", "quantity": 10},{"name": "Balloons", "quantity": 50}]
    >>> db.insert_multiple(items)
    [2, 3, 4]
    >>>

    In this case, we created a list of dictionaries called items and used the insert_multiple()method to insert the items. This method also returns a list of ids of the objects inserted.

    The todo_db.json file now looks like this:

    {
      "_default": {
        "1": { "name": "Book", "quantity": 5 },
        "2": { "name": "Cake", "quantity": 1 },
        "3": { "name": "Candles", "quantity": 10 },
        "4": { "name": "Balloons", "quantity": 50 }
      }
    }
    

    How to Retrieve Data from TinyDB

    There are several ways to retrieve data from your database. But you will need to create an instance of the Query class first. So, let's do that:

    >>> from tinydb import Query
    >>> Todo = Query()
    >>>
    

    You can use the db.search() method to retrieve data.

    >>> db.search(Todo.name == 'Book')
    [{'name': 'Book', 'quantity': 5}]
    >>> db.search(Todo.name == 'Copies')
    []
    >>>

    The search() method returns the list of items matching the query. If no such item is there, it returns an empty list.

    We can also use the get() method to get an item.

    >>> db.get(Todo.name == 'Book')
    {'name': 'Book', 'quantity': 5}
    >>> db.get(Todo.name == 'Copies')
    >>>

    The get() method returns only one matching document. If no document is matched, it returns None.

    To check whether a document exists in the database or not, we use the contains() method.

    >>> db.contains(Todo.name == 'Copies') 
    False
    >>> db.contains(Todo.name == 'Book')   
    True
    >>>
    

    We can also get the number of documents matching our query using the count() method.

    >>> db.insert({"name": "Balloons", "quantity": 500}) 
    5
    >>> db.count(Todo.name == 'Balloons') 
    2
    >>>
    

    To get the total number of stored documents in the database, we use the len() method.

    >>> len(db)
    5
    >>>
    

    To get all the documents in the database, we can use the all() method:

    >>> db.all()
    [{'name': 'Book', 'quantity': 5}, {'name': 'Cake', 'quantity': 1}, {'name': 'Candles', 'quantity': 10}, {'name': 'Balloons', 'quantity': 50}, {'name': 'Balloons', 'quantity': 500}]
    >>>
    

    How to Update Data in TinyDB

    The update() method takes the fields that the matching documents will have or a method that will update the documents. It can also take a condition to query an argument optionally.

    To update a document matching a query, we can do this:

    >>> db.update({'name': 'Books'}, Todo.name == 'Book')
    [1]
    >>>
    

    Here, we updated the name of the document to Books (its name was Book above).

    Sometimes, we need to update all the documents. In that case, we don't write the query argument.

    >>> db.update({'quantity': 10}) 
    [1, 2, 3, 4, 5]
    >>> db.all()
    [{'name': 'Books', 'quantity': 10}, {'name': 'Cake', 'quantity': 10}, {'name': 'Candles', 'quantity': 10}, {'name': 'Balloons', 'quantity': 10}, {'name': 'Balloons', 'quantity': 10}]
    >>>
    

    We updated the quantity of all the documents to 10.

    How to Delete Data in TinyDB

    To delete documents from the database, we use the remove() method. This method takes an optional condition and an optional list of document ids. If the condition is matched, the document will be deleted.

    >>> db.remove(Todo.name == 'Cake')                              
    [2]
    >>> db.all()                      
    [{'name': 'Books', 'quantity': 10}, {'name': 'Candles', 'quantity': 10}, {'name': 'Balloons', 'quantity': 10}, {'name': 'Balloons', 'quantity': 10}]
    >>> db.remove(Todo.name == 'Copies')
    []
    >>>
    

    To delete documents using the document id, we can write this code:

    >>> db.remove(doc_ids=[4,5]) 
    [4, 5]
    >>> db.all()
    [{'name': 'Books', 'quantity': 10}, {'name': 'Candles', 'quantity': 10}]
    >>>
    

    To delete everything from the database, we can use the truncate() method:

    >>> db.truncate()
    >>> db.all()
    []
    >>>
    

    Wrapping Up

    In this article, we have talked about TinyDB and how to perform CRUD operations on the database.

    This was just a basic tutorial. To learn more about the advanced usages of TinyDB, you can go through its official documentation.

    Thanks for reading!

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