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Author: alien
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Khóa học miễn phí TinyDB – Introduction nhận dự án làm có lương
TinyDB – Introduction
What is TinyDB?
TinyDB, written in pure Python programming language, is a small and lightweight document-orineted database with no external dependencies. It provides simple APIs that makes it easy to use. We can use TinyDB database for small project applications without any configuration.
TinyDB module, available as a third-party module for Python programs, can be used to store, retereive, and modify the data in JSON format.
Features of TinyDB
TinyDB is a clean and hustle-free database to operate several formats of documents. It has the following features.
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Really tiny − TinyDB database is truly tiny in nature with only 1800 lines of code and 1600 lines tests.
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Easy to use − TinyDB is easy to use because of its simple and clean APIs.
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Document oriented − In TinyDB, we can store any document. The document will be represented as dict.
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Independent − The TinyDB database is independent of any external server and external dependencies from PyPI.
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Compatible with Python 3.6 or latest − TinyDB is tested and compatible with Python 3.6 and latest. It also works fine with PyPY3.
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Extensible − TinDB is easily extensible either by writing new storages or by modifying the behaviour of storages.
Advantages of TinyDB
TinyDB provide various benefits for students, users, and developers.
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TinyDB is open-sourced database aand it does not require any external configirations.
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It is quite easy-to-use, and the user can effortlessly handle documents.
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It automatically stores documents in the database.
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TinyDB is ideal in case of personal projects where we need to install some data.
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It is suitable for small applications that would be blown away by large databases like SQL or an external DB server.
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It uses a simple command line and query to operate data.
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There is 100% test coverage i.e., no explanation needed.
Limitatations of TinyDB
TinyDB will not be the right choice for your project if you need to −
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create indexes for tables,
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manage relationships between tables,
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use an HTTP server, or
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access from multiple processors.
Comparison with Other Databases
The following table highlights how TinyDB is different from MySQL and Oracle databases −
Comparison Basis MySQL Oracle TinyDB Configurations Several Configurations Several Configurations Less Configurations, lightweight database Complicated Yes Yes No, easy-to-use and hustle-free Affordable No No Affordable than other databases Manageable Big database, hence difficult to manage Big database, hence difficult to manage Small and manageable
Khóa học lập trình tại Toidayhoc vừa học vừa làm dự án vừa nhận lương: Khóa học lập trình nhận lương tại trung tâm Toidayhoc
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Khóa học miễn phí TinyDB – Retrieve Data nhận dự án làm có lương
TinyDB – Retrieve Data
There are numerous ways with the help of which you can retrieve data from a TinyDB database. But to use those ways, you first need to create an instance of the Query class as follows −
from tinydb import Query Student = Query()
Here, Student is the name of the database.
Let”s check the various ways to retrieve the information from a TinyDB database.
Data Retrieval Using the Search() Method
The search() method, as its name implies, returns the list of items that mathches the query we provided, otherwise it will return an empty list.
For this and other examples, we will be using the following student database data −
[
{
"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"
}
]
Let”s take an example to understand the search() method −
from tinydb import TinyDB, Query
db = TinyDB("leekha.json")
student = Query()
db.search(student.subject == ''TinyDB'' )
The above query will retrieve the the following output from the student database −
[
{
"roll_number":1,
"st_name":"elen",
"mark":250,
"subject":"TinyDB",
"address":"delhi"
},
{
"roll_number":5,
"st_name":"karan",
"mark":275,
"subject":"TinyDB",
"address":"benglore"
}
]
Data Retrieval Using the get() Method
As opposed to the search() method, the get() method returns only one matching document. It will return None, otherwise. For example, let”s take the following code −
from tinydb import TinyDB, Query student = Query() db.get(student.subject == ''TinyDB'' )
The above query will retrieve the following data from the student database.
[{''roll_number'': 1, ''st_name'': ''elen'', ''mark'': 250, ''subject'': ''TinyDB'', ''address'': ''delhi''}]
Data Retrieval using the all() Method
The all() method returns all the documents in the database. For example,
db.all()
It will retrieve the entire data from the 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"
}
]
Data Retrieval Using the for Loop
The for loop also returns all the documents in the database. For example,
for info in db: print(info)
Just like the all() method, it will retrieve all the rows from the student database.
Khóa học lập trình tại Toidayhoc vừa học vừa làm dự án vừa nhận lương: Khóa học lập trình nhận lương tại trung tâm Toidayhoc
