Tag: equals doc import sum imp UK count () string border
1. Get Data
For post in Post.objects:print (Post.title) for post in post.objects:
Print (Post.title)
Print (' = ' * Len (post.title))
If Isinstance (post, Textpost):
Print (post.content)
If Isinstance (post, Linkpost):
Print (' Link: {} '. Format (Post.link_url))
#
Show DataFor post in Post.objects:print (Post.title) for post in post.objects:
Print (Post.title)
Print (' = ' * Len (post.title))
If Isinstance (post, Textpost):
Print (post.content)
If Isinstance (post, Linkpost):
Print (' Link: {} '. Format (Post.link_url))
# Get specific data content for post in post.objects (tags= ' MongoDB '): Print (post.title) # Get the number of specific data content num_posts = post.objects (tags= ' Mon Godb '). Count () print (' Found {} posts with tag ' MongoDB '. Format (num_posts)) # Author's country (foreign key) uk_pages = Page.objects (author__ country= ' UK ')-ne-unequal-lt-less-LTE-less than equals-GT-greater-than-GTE-greater than or equal-not-take inverse Q (age__not__mod=5)-in-value in List-nin-value not in list- MoD-modulo (remainder)-all-same as the value of the list-size-sizes of the array-exists-the value of the field exists Young_users = Users.objects (age__lte=18)
string Query-exact– string field exactly matches this value-iexact– string field exactly matches this value (case sensitive)-The contains– string field contains this value-the icontains– string field contains this value (case sensitive)-startswith– The string field starts with this value-the istartswith– string field starts with this value (case sensitive)-the endswith– string field is terminated by this value-the iendswith– string field is terminated by this value (case sensitive)-match– execution $elemMa TCH operation, so you can use the document instance in an array of users = user.objects[10:15]
Users = User.objects.skip (Ten). Limit (5) summation: Yearly_expense = Employee.objects.sum (' salary ') averaging: Mean_age = User.objects.average (' age ') asks which ages (de-weight) are included all_age = User.objects.distinct (' age ') to remove certain conditions (not including ages less than 18) User.objects.exclude (age__lt=18) gets only one field User.objects.only (' Age ') user.objects (age=12). Only (' name '). First () # Define the Query method class blogpost (Document):
title = Stringfield ()
Published = Booleanfield ()
@queryset_manager
def live_posts (Doc_cls, Queryset):
Return Queryset.filter (published=true) blogpost (title= ' test1 ', Published=false). Save () blogpost (title= ' test2 ', published=true). Save () Assert Len (blogpost.objects) = = 2assert Len (blogpost.live_posts ()) = = 1 # get only the field data you want >>> Class Film (Document): ... title = Stringfield () ... year = Intfield () ... rating = Intfield (default=3) ...>> > Film (title= ' The Shawshank Redemption ', year=1994, rating=5). Save () >>> f = Film.objects.only (' title '). First () >>> F.title ' The Shawshank Redemption ' >>> f.year # none>>> f.rating # Default Value3
Advanced QuerySometimes multiple conditions need to be combined, and the method mentioned above will not meet the requirements. You can then use the Q Class of Mongoengine. It can carry multiple query criteria & (with) and | (or) operation. For example, the following statement is a query for all British users older than or equal to 18 years old, or all users older than or equal to 20 years old. From mongoengine.queryset.visitor import q user.objects ((q (country= ' UK ') & Q (age__gte=18)) | Q (AGE__GTE=20))
# Sort from datetime import datetime
Class blogpost (Document):
title = Stringfield ()
Published_date = Datetimefield ()
Meta = {
' Ordering ': ['-published_date ']
}blog_post_1 = blogpost (title= "blog post #1") Blog_post_1.published_date = DateTime (1, 5, 0, 0, 0) blog_post_2 = Blog Post (title= "blog post #2") Blog_post_2.published_date = DateTime (1, 6, 0, 0, 0) blog_post_3 = blogpost (title= "blog Po St #3 ") Blog_post_3.published_date = DateTime (2010, 1, 7, 0, 0, 0)
Blog_post_1.save () Blog_post_2.save () Blog_post_3.save ()
# get the "first" blogpost using default ordering# from BlogPost.meta.orderinglatest_post = BlogPost.objects.first () Asser T latest_post.title = = "Blog post #3" # Override default ordering, order blogposts by "published_date" First_post = blogpost . objects.order_by ("+published_date"). First ()
Django combined with Mongoengine for MongoDB operation (ii)
