Peewee is a Python library based on ORM (Object-Relational Mapping). Is is supports SQLite, MySQL, PostgreSQL, and Cockroach databases. In the following this tutorial, we will be learning how to insert a new record, delete a record, create an index, and a many more using the Peewee library function in the Python programming language. It develops by a US-based software engineer Charles Leifer in October 2010.
The Field Types in Peewee
This model define the storage type of the model.
| Field Type | SQLite | PostgreSQL | MySQL |
| CharField | Varchar | Varchar | Varchar |
| TextField | Text | Text | Longtext |
| DateTimeField | Datetime | Timestamp | Datetime |
| IntegerField | Integer | Integer | Integer |
| BooleanField | Smallint | Boolean | Bool |
| FloatField | Real | Real | Real |
| DoubleField | Real | Double Precision | Double Precision |
| BigIntegerField | Integer | Bigint | Bigint |
| DecimalField | Decimal | Numeric | Numeric |
| PrimaryKeyField | Integer | Serial | Integer |
| ForeignKeyField | Integer | Integer | Integer |
| DateField | Date | Date | Date |
| TimeField | Time | Time | Time |
Example
# importing the required libraries
import peewee
import datetime
# creating a database
db = peewee.SqliteDatabase(‘testSpace.db’)
# defining a class as Notes
class Notes(peewee.Model):
text = peewee.CharField()
created = peewee.DateField(default = datetime.date.today)
class Meta:
database = db
db_table = ‘notes’
# creating table
Notes.create_table()
noteOne = Notes.create(text = ‘Book Store’)
noteOne.save()
noteTwo = Notes.create(text = ‘Copy Store’, created = datetime.date(2022, 12, 6))
noteTwo.save()
noteThree = Notes.create(text = ‘Card Store’, created = datetime.date(2022, 12, 6))
noteThree.save()
noteFour = Notes.create(text = ‘pen Store’)
noteFour.save()
Output
sqlite> select * from notes; 1|Book Store|2022-12-07 2|Copy Store|2022-12-06 3|Card Store|2022-12-06 4|Pen Store|2022-12-07
Meta Class Attributes
- Database
- db_table
- Indexes
- primary_key
- Constraints
- Schema
- Temporary
- depends_on
- without_rowid
Methods in Model class
- Classmethod alias()
- Classmethod select()
- Classmethod update()
- classmethod insert()
- classmethod delete()
- classmethod get()
- get_id()
- save()
- classmethod bind()
Field Class
- column_name (str)
- primary_key (bool)
- constraints (list)
- choices (list)
- null (bool)
- index (bool)
- unique (bool)
- Default
- collation (str)
- help_text (str)
- verbose_name (str)
Numeric Field classes
- IntegerField
- BigIntegerField
- SmallIntegerField
- FloatField
- DoubleField
- DecimalField
Text fields
- CharField
- FixedCharField
- TextField
Binary fields
- BlobField
- BitField
- BigBitField
- UUIDField
Date and Time fields
- DateTimeField
- DateField
- TimeField
ForeignKeyField
- model (Model)
- field (Field)
- backref (str)
- on_delete (str)
- on_update (str)
- lazy_load (bool)
Other Field Types
- IPField
- BooleanField
- AutoField
- IdentityField
Insert a New Record
Example of Insert a new record
from peewee import *
db = SqliteDatabase('mydatabase.db')
class User (Model):
name=TextField()
age=IntegerField()
class Meta:
database=db
db_table='User'
db.create_tables([User])
rec1=User(name="Tanisha", age=15)
rec1.save()
a=User(name="Amit", age=18)
a.save()
User.create(name="Swati", age=22)
q = User.insert(name='Abhinav', age=25)
q.execute()
db.close()
Bulk Inserts
Bulk Insert Peewee provides two methods :
- bulk_create
- insert_many
insert_many()
rows=[{"name":"Rohit", "age":18}, {"name":"Ritika", "age":22}]
q=User.insert_many(rows)
q.execute()
bulk_create()
a=User(name="Kiran", age=19) b=User(name='Lata', age=20) User.bulk_create([a,b])
Following code uses both insert_many() and bulk_create()
from peewee import *
db = SqliteDatabase('mydatabase.db')
class User (Model):
name=TextField()
age=IntegerField()
class Meta:
database=db
db_table='User'
db.create_tables([User])
rows=[{"name":"Rohit", "age":18}, {"name":"Ritika", "age":23}]
q=User.insert_many(rows)
q.execute()
a=User(name="mohit", age=15)
b=User(name='mohine', age=16)
User.bulk_create([a,b])
db.close()
Select Records
Following code uses select Record
rom peewee import *
db = SqliteDatabase('mydatabase.db')
class User (Model):
name=TextField()
age=IntegerField()
class Meta:
database=db
db_table='User'
rows=User.select()
print (rows.sql())
for row in rows:
print ("name: {} age: {}".format(row.name, row.age))
db.close()
Filters
| logical operators | Describe |
| == | a equals b |
| < | a is less than b |
| > | a is greater than b |
| <= | a is less than or equal to b |
| >= | a is greater than or equal to b |
| != | a is not equal to b |
| << | a IN b, where b is a list or query |
| >> | a IS b, where y is None and NULL |
| % | a LIKE b where b may contain wildcards |
| ** | a ILIKE b where b may contain wildcards |
| ^ | a XOR b |
| ~ | Unary negation |
Following code displays name with rupees>=600:
rows=User.select().where (User.rupees>=600)
for row in rows:
print ("name: {} rupees: {}".format(row.name, row.rupees))
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