MongoDB存儲----文檔型數據庫
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利用pymongo鏈接MongoDB
View Codeimport pymongo client = pymongo.MongoClient(host='localhost', port=27017) # 或 pymongo.MongoClient('mongodb://localhost:23017/') # 默認端口爲:27017
# pymongo.MongoClient()方法
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指定數據庫
# 指定操做test數據庫
# db = client.test 或 db = client['test'] -
指定集合
# 指定一個集合要操做的集合students
# collection = db.students 或 collection = db['students'] -
插入數據
插入單條數據import pymongo # 鏈接MongoDB client = pymongo.MongoClient(host='localhost', port=27017) # 指定數據庫 db = client.test # 指定集合 collection = db.students # 數據 student = { 'id': '20180001', 'name': 'Jordan', 'age': 20, 'gender': 'male' } # 利用insert_one()方法插入一條數據 result = collection.insert_one(student) print(result) # 運行輸出：<pymongo.results.InsertOneResult object at 0x11089b448> # 在MongoDB中，每條數據其實都有一個_id屬性來惟一標識。若是沒有顯式指明該屬性，MongoDB會自動產生一個ObjectId類型的_id屬性。 # 使用 insert_one()和 insert_many()方法來分別插入單條記錄和多條記錄
插入多條數據import pymongo client = pymongo.MongoClient(host='localhost', port=27017) db = client.test collection = db.students student1 = { 'id': '20180002', 'name': 'Lee Hua', 'age': 20, 'gender': 'male' } student2 = { 'id': '20180003', 'name': 'Mike', 'age': 21, 'gender': 'male' } result = collection.insert_many([student1, student2]) print(result) print(result.inserted_ids) # 調用inserted_ids屬性能夠獲取數據的_id列表 # 運行輸出： <pymongo.results.InsertManyResult object at 0x110826d88> [ObjectId('5d28b293e834575faf929428'), ObjectId('5d28b293e834575faf929429')]
# insert_one()方法 和 insert_many()方法
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查詢
查詢單條數據import pymongo client = pymongo.MongoClient(host='localhost', port=27017) db = client.test collection = db.students result = collection.find_one({'name': 'Lee Hua'}) print(result) # 輸出： {'_id': ObjectId('5d28b293e834575faf929428'), 'id': '20180002', 'name': 'Lee Hua', 'age': 20, 'gender': 'male'}
查詢多條數據import pymongo client = pymongo.MongoClient(host='localhost', port=27017) db = client.test collection = db.students result = collection.find() print(result) for r in result: print(r) # find()方法返回一個迭代器，用for循環逐條輸出 # 輸出結果： <pymongo.cursor.Cursor object at 0x10e0f7320> {'_id': ObjectId('5d28ae0360105a198d9d501a'), 'id': '20180001', 'name': 'Jordan', 'age': 20, 'gender': 'male'} {'_id': ObjectId('5d28ae2d8b3d004feb604874'), 'id': '20180001', 'name': 'Jordan', 'age': 20, 'gender': 'male'} {'_id': ObjectId('5d28b293e834575faf929428'), 'id': '20180002', 'name': 'Lee Hua', 'age': 20, 'gender': 'male'} {'_id': ObjectId('5d28b293e834575faf929429'), 'id': '20180003', 'name': 'Mike', 'age': 21, 'gender': 'male'}
# find_one()方法 和 find()方法
能夠在這兩個方法裏面添加條件，如：html
find(
{
'name': {'$regex': '^M.*'}
}
)
這裏查找的是以'M'開頭的名字的那些數據，$regex指定的是正則表達式，
^M.*是一條正則表達式
更多功能符號（如$regex）、數值比較符號的查看MongoDB官方文檔：https://docs.mongodb.com/?searchProperty=manual
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計數
View Codeimport pymongo client = pymongo.MongoClient(host='localhost', port=27017) db = client.test collection = db.students count = collection.count_documents( { 'id': {'$regex': '^(2018)'} } ) print(count) # 輸出id爲2018開頭的數據的條數
# collection.count_documents({條件}) 方法 -
排序
View Code1 import pymongo 2 3 client = pymongo.MongoClient(host='localhost', port=27017) 4 db = client.test 5 collection = db.students 6 7 result = collection.find().sort('id', pymongo.ASCENDING) 8 for r in result: 9 print(r) 10 11 12 # 以id升序輸出全部的數據： 13 {'_id': ObjectId('5d28ae0360105a198d9d501a'), 'id': '20180001', 'name': 'Jordan', 'age': 20, 'gender': 'male'} 14 {'_id': ObjectId('5d28ae2d8b3d004feb604874'), 'id': '20180001', 'name': 'Jordan', 'age': 20, 'gender': 'male'} 15 {'_id': ObjectId('5d28b293e834575faf929428'), 'id': '20180002', 'name': 'Lee Hua', 'age': 20, 'gender': 'male'} 16 {'_id': ObjectId('5d28b293e834575faf929429'), 'id': '20180003', 'name': 'Mike', 'age': 21, 'gender': 'male'} 17 18 19 # sort()方法進行排序 20 # pymongo.ASCENDING指定升序 21 # pymongo.DESCENDING指定降序
# sort()方法
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偏移
skip()方法import pymongo client = pymongo.MongoClient(host='localhost', port=27017) db = client.test collection = db.students results = collection.find().sort('id', pymongo.DESCENDING).skip(1) print( [ result['id'] for result in results ] ) # 輸出： ['20180002', '20180001', '20180001'] # skip(1)表示偏移1，即忽略前面一個元素
limit()方法import pymongo client = pymongo.MongoClient(host='localhost', port=27017) db = client.test collection = db.students results = collection.find().sort('id', pymongo.DESCENDING).skip(1).limit(2) print( [ result['id'] for result in results ] ) # 輸出： ['20180002', '20180001'] # limit(2) 即表示限制輸出的數據條數爲兩條
# 數據量很大時，不使用大的偏移量來查詢數據
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更新
update_one()方法import pymongo client = pymongo.MongoClient(host='localhost', port=27017) db = client['test'] collection = db['students'] # 查詢條件：age >= 20 query_condition = { 'age': {'$gte': 20} } # 更新條件：數據的age加1 update_condition = { '$inc': {'age': 1} } result = collection.update_one(query_condition, update_condition) print(result) print(result.matched_count, result.modified_count) # 輸出： <pymongo.results.UpdateResult object at 0x110a11c88> 1 1 # 返回的結果是UpdateResul類型的 # 調用matched_count屬性，得到匹配數據的條數 # 調用modified_count屬性，得到影響數據的條數 # $gte ： 大於等於 # $inc ： 將字段遞增指定的值 # updata_one()更新與篩選器匹配的單個文檔
update_many()方法import pymongo client = pymongo.MongoClient(host='localhost', port=27017) db = client['test'] collection = db['students'] query_condition = { 'age': {'$gte': 20} } update_condition = { '$inc': {'age': 1} } result = collection.update_many(query_condition, update_condition) print(result) print(result.matched_count, result.modified_count) # 輸出： <pymongo.results.UpdateResult object at 0x111c84448> 4 4
# update_one()方法 和 update_many()方法
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刪除
delete_one()方法import pymongo client = pymongo.MongoClient(host='localhost', port=27017) db = client['test'] collection = db['students'] result = collection.delete_one({'age': 21}) print(result.deleted_count) # delete_one()方法：刪除第一條符合條件的數據 # delete_count屬性：獲取刪除數據的條數
delete_many()方法import pymongo client = pymongo.MongoClient(host='localhost', port=27017) db = client['test'] collection = db['students'] result = collection.delete_many({'age': 21}) print(result.deleted_count) # delete_many()方法：刪除全部符合條件的數據
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PyMongo的詳細用法：http://api.mongodb.com/python/current/api/pymongo/collection.html