The “Logical OR” operator combines multiple conditions and evaluates to True only if either of the condition is met. TinyDB Logical OR operates on two queries of a database. If any one of the queries is True, TinyDB will fetch the required data. On the other hand, if both the queries are False, it will return a blank.

Syntax

The syntax of TinyDB Logical OR is as follows −

db.search((Query().(query1) | (Query().(query2)

Here, field represents the part of data that we want to access. Query() is the object created of our JSON table named student. It will fetch the data if any one of the conditions is met, otherwise it will return a blank.

Let”s take a couple of examples and see how it works. We will use the same student database that we have used in all the previous chapters.

Example 1

Let”s see what our TinyDB Student database returns when we apply Logical OR on the “st_name” and “subject” fields and check the following conditions: “st_name=lakhan” and “subject=TinyDB” −

from tinydb import TinyDB, Query
db = TinyDB(''student.json'')
db.search ((Query().st_name == ''lakan'') | (Query().subject == ''TinyDB''))

This query will fetch the following rows −

[
   {
      "roll_number":1,
      "st_name":"elen",
      "mark":250,
      "subject":"TinyDB",
      "address":"delhi"
   },
   {
      "roll_number":4,
      "st_name":"lakhan",
      "mark":200,
      "subject":"MySQL",
      "address":"mumbai"
   },
   {
      "roll_number":5,
      "st_name":"karan",
      "mark":275,
      "subject":"TinyDB",
      "address":"benglore"
   }
]

Example 2

In this example, let”s apply Logical OR on the “subject” and “roll_number” fields −

from tinydb import TinyDB, Query
db = TinyDB(''student.json'')
db.search((student.subject.search(''M'')) | (student.roll_number < 5))

This query will fetch all the rows where the “subject” field starts with the letter “M” or the “roll_number” is less than “5”.

[
   {
      "roll_number":1,
      "st_name":"elen",
      "mark":250,
      "subject":"TinyDB",
      "address":"delhi"
   },
   {
      "roll_number":2,
      "st_name":"Ram",
      "mark":[
         250,
         280
      ],
      "subject":[
         "TinyDB",
         "MySQL"
      ],
      "address":"delhi"
   },
   {
      "roll_number":3,
      "st_name":"kevin",
      "mark":[
         180,
         200
      ],
      "subject":[
         "oracle",
         "sql"
      ],
      "address":"keral"
   },
   {
      "roll_number":4,
      "st_name":"lakhan",
      "mark":200,
      "subject":"MySQL",
      "address":"mumbai"
   }
]

Prerequisite for TinyDB setup

To install TinyDB, you must have Python 3.6 or newer installed in your system. You can go to the link and select the latest version for your OS, i.e., Windows and Linux/Unix. We have a comprehensive tutorial on Python, which you can refer at

Installing TinyDB

You can install TinyDB in three different ways: using the Pack Manager, from its Source, or from GitHub.

Using the Package Manager

The latest release versions of TinyDB are available over both the package managers, pip and conda. Let us check how you can use them to install TinyDB −

To install TinyDB using pip, you can use the following command −

pip install tinydb

To install TinyDB via conda-forge, you can use the following command −

conda install -c conda-forge tinydb

From Source

You can also install TinyDB from source distribution. Go to link to download the files and building it from source.

From GitHub

To install TinyDB using GitHub, grab the latest development version, unpack the files, and use the following command to install it −

pip install

Setting up TinyDB

Once installed, use the following steps to set up the TinyDB database.

Step 1: Import TinyDB and its Query

First, we need to import TinyDB and its Query. Use the following command −

from tinydb import TinyDB, Query

Step 2: Create a file

TinyDB database can store data in many formats like XML, JSON, and others. We will be creating a JSON file by using the following file −

db = TinyDB(''Leekha.json'')

The above command will create an instance of TinyDB class and pass the file Leekha.Json to it. This is the file where our data will be stored. Now, the TinyDB database set up is ready, and you can work on it. We can now insert data and operate the value in the database.

Uinstalling TinyDB

If in case you need to uninstall TinyDB, you can use the following command −

pip uninstall tinydb

TinyDB provides the search() method to help you search any data from a document. Along with the query() object, the search() method can be used to find the data in a JSON file. We have various ways in which we can use the search() method on a TinyDB database.

Method 1: TinyDB search() with Existence of a Field

We can search the data from a database based on the existence of a field. Let”s understand it with an example. For this and other examples, we will be using the following student database.

[
   {
      "roll_number":1,
      "st_name":"elen",
      "mark":250,
      "subject":"TinyDB",
      "address":"delhi"
   },
   {
      "roll_number":2,
      "st_name":"Ram",
      "mark":[
         250,
         280
      ],
      "subject":[
         "TinyDB",
         "MySQL"
      ],
      "address":"delhi"
   },
   {
      "roll_number":3,
      "st_name":"kevin",
      "mark":[
         180,
         200
      ],
      "subject":[
         "oracle",
         "sql"
      ],
      "address":"keral"
   },
   {
      "roll_number":4,
      "st_name":"lakan",
      "mark":200,
      "subject":"MySQL",
      "address":"mumbai"
   },
   {
      "roll_number":5,
      "st_name":"karan",
      "mark":275,
      "subject":"TinyDB",
      "address":"benglore"
   }
]

Example

The search query based on the existence of a field is as follows −

from tinydb import Query
student = Query()
db.search(student.address.exists())

The above query will retrieve the following data from the student file −

[
   {
      "roll_number":1,
      "st_name":"elen",
      "mark":250,
      "subject":"TinyDB",
      "address":"delhi"
   },
   {
      "roll_number":2,
      "st_name":"Ram",
      "mark":[
         250,
         280
      ],
      "subject":[
         "TinyDB",
         "MySQL"
      ],
      "address":"delhi"
   },
   {
      "roll_number":3,
      "st_name":"kevin",
      "mark":[
         180,
         200
      ],
      "subject":[
         "oracle",
         "sql"
      ],
      "address":"keral"
   },
   {
      "roll_number":4,
      "st_name":"lakan",
      "mark":200,
      "subject":"MySQL",
      "address":"mumbai"
   },
   {
      "roll_number":5,
      "st_name":"karan",
      "mark":275,
      "subject":"TinyDB",
      "address":"benglore"
   }
]

Method 2: TinyDB search() with Regular Expression

We can search for a particular data from a database using regular expression (Regex). Let”s understand how it works with a couple of examples.

Example 1

Full item search matching the Regular Expression −

from tinydb import Query
student = Query()
db.search(student.st_name.matches(''[aZ]*''))

This query will produce the following output −

[
   {
      "roll_number":1,
      "st_name":"elen",
      "mark":250,
      "subject":"TinyDB",
      "address":"delhi"
   },
   {
      "roll_number":2,
      "st_name":"Ram",
      "mark":[
         250,
         280
      ],
      "subject":[
         "TinyDB",
         "MySQL"
      ],
      "address":"delhi"
   },
   {
      "roll_number":3,
      "st_name":"kevin",
      "mark":[
         180,
         200
      ],
      "subject":[
         "oracle",
         "sql"
      ],
      "address":"keral"
   },
   {
      "roll_number":4,
      "st_name":"lakan",
      "mark":200,
      "subject":"MySQL",
      "address":"mumbai"
   },
   {
      "roll_number":5,
      "st_name":"karan",
      "mark":275,
      "subject":"TinyDB",
      "address":"benglore"
   }
]

Example-2

Case-sensitive search with Regular Expression −

from tinydb import Query
import re
student = Query()
db.search(student.st_name.matches(''lakan'', flags=re.IGNORECASE))

It wil produce the following output −

[{
   ''roll_number'': 4,
   ''st_name'': ''lakan'',
   ''mark'': 200,
   ''subject'': ''MySQL'',
   ''address'': ''mumbai''
}]

Example-3

Any part of the item matching with Regular Expression −

from tinydb import Query
student = Query()
db.search(student.st_name.search(''r+''))

This query will produce the following output −

[{
   ''roll_number'': 5,
   ''st_name'': ''karan'',
   ''mark'': 275,
   ''subject'': ''TinyDB'',
   ''address'': ''benglore''
}]

Method 3: TinyDB search() using a Substring

We can also use a substring while searching for a particular data from a TinyDB database. Let”s understand how it works with a couple of examples −

Example-1

Take a look at this query; it will fetch the all the rows where the “address” field is “delhi”.

from tinydb import Query
student = Query()
db.search(student[''address''] == ''delhi'')

It will produce the following output −

[
   {
      "roll_number":1,
      "st_name":"elen",
      "mark":250,
      "subject":"TinyDB",
      "address":"delhi"
   },
   {
      "roll_number":2,
      "st_name":"Ram",
      "mark":[
         250,
         280
      ],
      "subject":[
         "TinyDB",
         "MySQL"
      ],
      "address":"delhi"
   }
]

Example-2

In this query, we have used a slightly different syntax for the search() method.

from tinydb import Query
student = Query()
db.search(student.address.search(''mumbai''))

It will fetch all the rows where the “address” field is “mumbai”.

[{
   ''roll_number'': 4,
   ''st_name'': ''lakan'',
   ''mark'': 200,
   ''subject'': ''MySQL'',
   ''address'': ''mumbai''
}]

TinyDB can store data in many formats and we can easily reterive the stored data using various methods. But sometimes, we need to update the data, for which we can use the update() method.

For updating the database, we first need to create an instance of the Query class. You can use the following command for this purpose −

from tinydb import Query
Student = Query()

Here, Student is the name of our database.

The update() Method

Here is the syntax for the update() method −

db.update({ updated field: updated information… }, stable field: information)

Let”s take an example to understand how the update() method works. For this example, we will be using the following student database −

[
   {
      "roll_number":1,
      "st_name":"elen",
      "mark":250,
      "subject":"TinyDB",
      "address":"delhi"
   },
   {
      "roll_number":2,
      "st_name":"Ram",
      "mark":[
         250,
         280
      ],
      "subject":[
         "TinyDB",
         "MySQL"
      ],
      "address":"delhi"
   },
   {
      "roll_number":3,
      "st_name":"kevin",
      "mark":[
         180,
         200
      ],
      "subject":[
         "oracle",
         "sql"
      ],
      "address":"keral"
   },
   {
      "roll_number":4,
      "st_name":"lakan",
      "mark":200,
      "subject":"MySQL",
      "address":"mumbai"
   },
   {
      "roll_number":5,
      "st_name":"karan",
      "mark":275,
      "subject":"TinyDB",
      "address":"benglore"
   }
]

As per the given data, the name of the student with the roll_number “1” is “elen”. The following query will update the student name to “Adam” −

from tinydb import TinyDB, Query
student = Query()
db.update({''st_name'' : ''Adam''}, student.roll_number == 1 )

It will return the id of the updated object −

[1]

Now, you can use the all() method to see the updated database −

db.all()

It will display the updated data −

[
   {
      "roll_number":1,
      "st_name":"Adam",
      "mark":250,
      "subject":"TinyDB",
      "address":"delhi"
   },
   {
      "roll_number":2,
      "st_name":"Ram",
      "mark":[
         250,
         280
      ],
      "subject":[
         "TinyDB",
         "MySQL"
      ],
      "address":"delhi"
   },
   {
      "roll_number":3,
      "st_name":"kevin",
      "mark":[
         180,
         200
      ],
      "subject":[
         "oracle",
         "sql"
      ],
      "address":"keral"
   },
   {
      "roll_number":4,
      "st_name":"lakan",
      "mark":200,
      "subject":"MySQL",
      "address":"mumbai"
   },
   {
      "roll_number":5,
      "st_name":"karan",
      "mark":275,
      "subject":"TinyDB",
      "address":"benglore"
   }
]

Sometimes, we need to update one or more fields of all the documents in a database. For this, we can use the update() mehod directly and don”t need to write the query argument. The following query will change the address of all the students to ”College_Hostel”−

db.update({''address'': ''College_Hostel''})

It will return the ids of the updated object −

[1,2,3,4,5]

Again, you can use the all() method to see the updated database.

db.all()

It will show the updated data −

[
   {
      "roll_number":1,
      "st_name":"Adam",
      "mark":250,
      "subject":"TinyDB",
      "address":"College_Hostel"
   },
   {
      "roll_number":2,
      "st_name":"Ram",
      "mark":[
         250,
         280
      ],
      "subject":[
         "TinyDB",
         "MySQL"
      ],
      "address":" College_Hostel "
   },
   {
      "roll_number":3,
      "st_name":"kevin",
      "mark":[
         180,
         200
      ],
      "subject":[
         "oracle",
         "sql"
      ],
      "address":" College_Hostel "
   },
   {
      "roll_number":4,
      "st_name":"lakan",
      "mark":200,
      "subject":"MySQL",
      "address":" College_Hostel "
   },
   {
      "roll_number":5,
      "st_name":"karan",
      "mark":275,
      "subject":"TinyDB",
      "address":" College_Hostel "
   }
]

Observe that the address fields of all the rows have the same data, i.e., ”College_Hostel”.