Django API operations common in MySQL statements

Background

Increase/delete/change/check How to operate the database

Model for importing databases

In [23°c]: from blog.models import people

"Add record"--Three ways

Method One: Directly using the CREATE function of the data-mode object

In []: People.objects.create (name= ' Shuaige ')

OUT[24]: <people:people object>

Note: Create a successful return object address

Method Two:

In [6]: Record = people (Name= ' Choubaguai ") in [7]: Record.save ()

Method Three:

In [9]: Record = people () in [ten]: Record.name = ' Andy ' in [All]: Record.save ()

"Delete Record"--Find the object and delete it using delete ()

First find the collection of objects you want to delete (id greater than 2)

in [+]: R_d = People.objects.filter (id__gt =2)

Use the Delete object to delete it

In []: R_d.delete () out[20]: (3, {' Blog. People ': 3})

Number of items that will return coral

"Change Record"-Find it first, re-assign the object property

(Change id=1 's name to Andyliu)

in [+]: People.objects.values_list () out[21]: [(1, ' Liudehua '), (2, ' zhangxueyou ')]in []: R_m = People.objects.get (id= 1) in [all]: R_m.name = ' Andyliu ' in [+]: R_m.save () in [+]: People.objects.values_list () out[25]: [(1, ' Andyliu '), (2, ' en Angxueyou ')]

"Check" This is equivalent to the SQL statement in MySQL in the SELECT statement, where there are many word statements to limit the query

1 Get all Record objects

All_record = People.objects.all ()

If you want to get an object value, you need to take an object out first and then remove the property from the object

in [+]: for record in All_record: ....: print (Record.id) ....: Print (Record.name) ....: 1andyliu2zhangx Ueyou

2 Gets the object with the specified value for a field

In [all]: R_p = People.objects.get (name= ' zhangxueyou ') in []: r_p.idout[12]: 2

Note: This usage is not commonly used, if you want to use, you must ensure that you find a certain existence of such a record, and must be unique, otherwise it will be error OH

3 conditional queries similar to where in MySQL use the filter function

First: Range comparison query for integers ()

Find an object with an ID greater than 1 and return it as a list of values

In []: People.objects.filter (id__gt=1). Values_list () out[15]: [(2, ' zhangxueyou '), (6, ' Andyliu ')]

Gt	Greater than
Gte	Greater than or equal
Lt	Less than
Lte	Less than or equal
Ne	Not equal to
In (can also be other data types)	In the given list: People.objects.filter (Id__in=[1, 3, 4]) returns a list of polls (ID values are 1 or 3 or 4, respectively).

in [+]: People.objects.filter (name__in=[' Andyliu ', ' zhangxueyou ']) out[16]: [<people:people object>, < People:people object> <people:people Object>]

4 Multi-filter query, one way is to use the filter function multiple times to

in [+]: People.objects.filter (id__gt=1). Filter (name= ' Andyliu ') out[17]: [<people:people object>]in [18]: People.objects.filter (id__gt=1). Filter (name= ' Andyliku ') out[18]: []

5 Object Data found (that is, the number of records that meet the criteria)

in [+]: People.objects.count ()

OUT[25]: 3

Equals:

in [+]: People.objects.all (). Count ()

OUT[26]: 3

The length of the meeting condition

in [+]: People.objects.filter (name= ' Andyliu '). Count () out[24]: 2

6 order_by () function, ascending/Descending

-negative indicates that you want to sort in descending order

in [+]: p = People.objects.order_by ('-id ') in [all]: For I in P:print (i.id) ....: 621

7 haha next may be a query about time (to be continued)

This article is from the "Tridewah operation and maintenance work Road" blog, please be sure to keep this source http://cuidehua.blog.51cto.com/5449828/1776023

Django API operations common in MySQL statements