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Python MongoDB - 删除文档
您可以使用MongoDB的remove()方法删除集合中的文档。此方法接受两个可选参数 -
删除条件指定删除文档的条件。
只有一个,如果您传递 true 或 1 作为第二个参数,则只会删除一个文档。
句法
以下是 remove() 方法的语法 -
>db.COLLECTION_NAME.remove(DELLETION_CRITTERIA)
例子
假设我们创建了一个集合并向其中插入了 5 个文档,如下所示 -
> use testDB switched to db testDB > db.createCollection("myColl") { "ok" : 1 } > data = [ ... {"_id": "1001", "name": "Ram", "age": "26", "city": "Hyderabad"}, ... {"_id": "1002", "name": "Rahim", "age": 27, "city": "Bangalore"}, ... {"_id": "1003", "name": "Robert", "age": 28, "city": "Mumbai"}, ... {"_id": "1004", "name": "Romeo", "age": 25, "city": "Pune"}, ... {"_id": "1005", "name": "Sarmista", "age": 23, "city": "Delhi"}, ... {"_id": "1006", "name": "Rasajna", "age": 26, "city": "Chennai"} ] > db.sample.insert(data) BulkWriteResult({ "writeErrors" : [ ], "writeConcernErrors" : [ ], "nInserted" : 6, "nUpserted" : 0, "nMatched" : 0, "nModified" : 0, "nRemoved" : 0, "upserted" : [ ] })
以下查询删除集合中名称值为 Sarmista 的文档。
> db.sample.remove({"name": "Sarmista"}) WriteResult({ "nRemoved" : 1 }) > db.sample.find() { "_id" : "1001", "name" : "Ram", "age" : "26", "city" : "Hyderabad" } { "_id" : "1002", "name" : "Rahim", "age" : 27, "city" : "Bangalore" } { "_id" : "1003", "name" : "Robert", "age" : 28, "city" : "Mumbai" } { "_id" : "1004", "name" : "Romeo", "age" : 25, "city" : "Pune" } { "_id" : "1006", "name" : "Rasajna", "age" : 26, "city" : "Chennai" }
如果您调用remove()方法而不传递删除条件,则集合中的所有文档都将被删除。
> db.sample.remove({}) WriteResult({ "nRemoved" : 5 }) > db.sample.find()
使用python删除文档
要从MangoDB集合中删除文档,可以使用delete_one()和delete_many()方法从集合中删除文档。
这些方法接受指定删除文档条件的查询对象。
如果匹配,detele_one() 方法会删除单个文档。如果未指定查询,此方法将删除集合中的第一个文档。
例子
以下 python 示例删除集合中 id 值为 1006 的文档。
from pymongo import MongoClient #Creating a pymongo client client = MongoClient('localhost', 27017) #Getting the database instance db = client['lpaksgf'] #Creating a collection coll = db['example'] #Inserting document into a collection data = [ {"_id": "1001", "name": "Ram", "age": "26", "city": "Hyderabad"}, {"_id": "1002", "name": "Rahim", "age": "27", "city": "Bangalore"}, {"_id": "1003", "name": "Robert", "age": "28", "city": "Mumbai"}, {"_id": "1004", "name": "Romeo", "age": 25, "city": "Pune"}, {"_id": "1005", "name": "Sarmista", "age": 23, "city": "Delhi"}, {"_id": "1006", "name": "Rasajna", "age": 26, "city": "Chennai"} ] res = coll.insert_many(data) print("Data inserted ......") #Deleting one document coll.delete_one({"_id" : "1006"}) #Retrieving all the records using the find() method print("Documents in the collection after update operation: ") for doc2 in coll.find(): print(doc2)
输出
Data inserted ...... Documents in the collection after update operation: {'_id': '1001', 'name': 'Ram', 'age': '26', 'city': 'Hyderabad'} {'_id': '1002', 'name': 'Rahim', 'age': '27', 'city': 'Bangalore'} {'_id': '1003', 'name': 'Robert', 'age': '28', 'city': 'Mumbai'} {'_id': '1004', 'name': 'Romeo', 'age': 25, 'city': 'Pune'} {'_id': '1005', 'name': 'Sarmista', 'age': 23, 'city': 'Delhi'}
同样, pymongo的delete_many()方法删除所有满足指定条件的文档。
例子
以下示例删除集合中年龄值大于 26 的所有文档 -
from pymongo import MongoClient #Creating a pymongo client client = MongoClient('localhost', 27017) #Getting the database instance db = client['sampleDB'] #Creating a collection coll = db['example'] #Inserting document into a collection data = [ {"_id": "1001", "name": "Ram", "age": "26", "city": "Hyderabad"}, {"_id": "1002", "name": "Rahim", "age": "27", "city": "Bangalore"}, {"_id": "1003", "name": "Robert", "age": "28", "city": "Mumbai"}, {"_id": "1004", "name": "Romeo", "age": "25", "city": "Pune"}, {"_id": "1005", "name": "Sarmista", "age": "23", "city": "Delhi"}, {"_id": "1006", "name": "Rasajna", "age": "26", "city": "Chennai"} ] res = coll.insert_many(data) print("Data inserted ......") #Deleting multiple documents coll.delete_many({"age":{"$gt":"26"}}) #Retrieving all the records using the find() method print("Documents in the collection after update operation: ") for doc2 in coll.find(): print(doc2)
输出
Data inserted ...... Documents in the collection after update operation: {'_id': '1001', 'name': 'Ram', 'age': '26', 'city': 'Hyderabad'} {'_id': '1004', 'name': 'Romeo', 'age': '25', 'city': 'Pune'} {'_id': '1005', 'name': 'Sarmista', 'age': '23', 'city': 'Delhi'} {'_id': '1006', 'name': 'Rasajna', 'age': '26', 'city': 'Chennai'}
如果您调用delete_many() 方法而不传递任何查询,则此方法将删除集合中的所有文档。
coll.delete_many({})