django ORM create

Brief example

from django.db import models

class Person(models.Model):
    first_name = models.CharField(max_length=30)
    last_name = models.CharField(max_length=30)

The above Personmodel will create such a table in the database:

CREATE TABLE myapp_person (
    "id" serial NOT NULL PRIMARY KEY,
    "first_name" varchar(30) NOT NULL,
    "last_name" varchar(30) NOT NULL
);

• The name of the table myapp_person, is automatically generated based on the metadata model may be overwritten to other names, see the Table names .
• id Field is added automatically, but this behavior can be overridden. See auto-increment primary key field .
• In this example CREATE TABLESQL statements using PostgreSQL syntax, it should be noted that based on Django settings file to use the appropriate SQL statements database type specified.

After a good django model definition, we need to add applications in settings.py in INSTALLED_APP

 

models syntax:

Property = models. Field type (field options)

Field Type:

　　1.BooleanField()　　True 0,False 1

　　2.CharField () max_length string length

　　3.DateField () date type

　　4.DateTimeField () datetime type

　　5.DecimalField () decimal type eg: money = models.DecimalField (max_digits = 7, decimal_places = 2) integrally 7, to one decimal place, the integer 5

　　6.FloatField () float type

　　7.InterField () int type

　　8.EmailField () varvhar type

　　9.URLField () varchar type

　　10.TextField () text type

　　11.ImageField () to save the image into the database image = models.ImageField (upload_to = "static / images /")　　

　　12.AutoField(primary_key=True)　　自增

Field options:

　　1.primary_key primary key is True, if not specified, Django automatically added

　　2.unique unique to True

　　3.default specify a default value

　　4.null to True to allow empty, the default is False

　　5.db_index the column index increased to True

　　6.db_column property is mapped to a table column names

　　7.blank True, the permit does not fill, the default is False

　　8.choices option field (enum) choices = two yuan ancestral

 

Yuan options:

　　class Meta：

　　　　Yuan option = ""

 

　　abstract = True This model is an abstract base class

　　app_label = "" If the model is defined outside of models, tell django, the model belongs to which application

　　db_table = "" model name of the corresponding data table (the default table name is a name of the application model name _)

　　ording = [ '- order_date'] is a list of tuples or strings, each string of a field name is preceded by a '-' represents a reverse order, there is no '-' represent positive sequence alignment, using the '? 'Represents a random ordering

　　　　ording = [ '- pud_date', 'author'] >> pub_date represented by reverse sort, sort by author positive sequence

　　verbose_name = "" alias objects, if not set, the class name will open as Django readme name, such as CamelCase becomes camel case

　　verbose_name_plural verbose_name complex