db.collection.updateMany()
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Definition定义
db.collection.updateMany(filter, update, options)
- Important
mongosh Method
This page documents a
mongosh
method. This is not the documentation for database commands or language-specific drivers, such as Node.js.For the database command, see the
update
command.For MongoDB API drivers, refer to the language-specific MongoDB driver documentation.
For the legacy
mongo
shell documentation, refer to the documentation for the corresponding MongoDB Server release:Updates all documents that match the specified filter for a collection.更新与集合的指定筛选器匹配的所有文档。
Syntax语法
The updateMany()
method has the following form:updateMany()
方法的形式如下:
db.collection.updateMany(
<filter>,
<update>,
{
upsert: <boolean>,
writeConcern: <document>,
collation: <document>,
arrayFilters: [ <filterdocument1>, ... ],
hint: <document|string> // Available starting in MongoDB 4.2.1
}
)
Parameters参数
The updateMany()
method takes the following parameters:updateMany()
方法采用以下参数:
filter | document | find() method are available.find() 方法中相同的查询选择器。{ } to update all documents in the collection. { } 以更新集合中的所有文档。 | ||||
update | document or pipeline |
| ||||
upsert | boolean | true , updateMany() either: true 时,updateMany() 可以:
filter fields are uniquely indexed.filter 字段进行唯一索引。false . false 。 | ||||
writeConcern | document | |||||
collation | document | collation 。collation collation 选项具有以下语法:collation: { locale field is mandatory; all other collation fields are optional. locale 字段是必需的;所有其他排序规则字段都是可选的。db.createCollection() ), the operation uses the collation specified for the collection.db.createCollection() ),则操作将使用为集合指定的排序规则。 | ||||
arrayFilters | array | $[<identifier>] filtered positional operator to define an identifier, which you then reference in the array filter documents. $[<identifier>] 筛选的位置运算符来定义标识符,然后在数组筛选文档中引用该标识符。Note <identifier> must begin with a lowercase letter and contain only alphanumeric characters. <identifier> 必须以小写字母开头,并且仅包含字母数字字符。$[identifier] ) in the update document, you must specify exactly one corresponding array filter document. $[identifier] ),必须指定一个对应的数组筛选器文档。x (possibly multiple times), you cannot specify the following for arrayFilters that includes 2 separate filter documents for x : x (可能多次),则不能为arrayFilters 指定以下内容,因为arrayFilters 包含两个单独的x 筛选文档:// INVALID // Example 1 arrayFilters for an Array Update Operations. arrayFilters 。 | ||||
hint | Document or string | hint for Update Operations. hint 。 |
Returns返回值
The method returns a document that contains:该方法返回一个文档,该文档包含:
A boolean如果操作在有写入关注的情况下运行,则布尔值acknowledged
astrue
if the operation ran with write concern orfalse
if write concern was disabledacknowledged
为true
;如果写入关注被禁用,则acknowledged
为false
matchedCount
containing the number of matched documents包含匹配的文档数modifiedCount
containing the number of modified documents包含修改的文档数upsertedId
containing the包含被打乱的文档的_id
for the upserted document_id
Access Control访问控制
On deployments running with 在使用authorization
, the user must have access that includes the following privileges:authorization
运行的部署上,用户必须具有包括以下权限的访问权限:
update
action on the specified collection(s).对指定集合执行操作。find
action on the specified collection(s).对指定集合执行操作。insert
action on the specified collection(s) if the operation results in an upsert.如果操作导致追加销售,则对指定集合执行操作。
The built-in role 内置角色readWrite
provides the required privileges.readWrite
提供所需的权限。
Behavior行为
updateMany()
updates all matching documents in the collection that match the 使用filter
, using the update
criteria to apply modifications.update
条件应用修改,更新集合中与filter
匹配的所有匹配文档。
Upsert
If 如果upsert: true
and no documents match the filter
, db.collection.updateMany()
creates a new document based on the filter
and update
parameters.upsert: true
并且没有文档与filter
匹配,那么db.collection.updateMany()
将根据筛选器和更新参数创建一个新文档。
If you specify 如果在分片集合上指定upsert: true
on a sharded collection, you must include the full shard key in the filter
. upsert: true
,则必须在filter
中包含完整的分片键。For additional 有关其他db.collection.updateMany()
behavior, see Sharded Collections.db.collection.updateMany()
行为,请参阅分片集合。
See Update Multiple Documents with Upsert.请参见使用Upsert更新多个文档。
Update with an Update Operator Expressions Document使用更新运算符表达式文档进行更新
For the modification specification, the 对于修改规范,db.collection.updateMany()
method can accept a document that only contains update operator expressions to perform.db.collection.updateMany()
方法可以接受只包含要执行的更新运算符表达式的文档。
For example:例如:
db.collection.updateMany(
<query>,
{ $set: { status: "D" }, $inc: { quantity: 2 } },
...
)
Update with an Aggregation Pipeline使用聚合管道更新
Starting in MongoDB 4.2, the 从MongoDB 4.2开始,db.collection.updateMany()
method can accept an aggregation pipeline [ <stage1>, <stage2>, ... ]
that specifies the modifications to perform. db.collection.updateMany()
方法可以接受一个指定要执行的修改的聚合管道[ <stage1>, <stage2>, ... ]
。The pipeline can consist of the following stages:管道可由以下阶段组成:
$addFields
and its alias及其别名$set
$project
and its alias及其别名$unset
$replaceRoot
and its alias及其别名$replaceWith
.
Using the aggregation pipeline allows for a more expressive update statement, such as expressing conditional updates based on current field values or updating one field using the value of another field(s).使用聚合管道可以实现更具表达力的更新语句,例如基于当前字段值表达条件更新,或者使用另一个字段的值更新一个字段。
For example:例如:
db.collection.updateMany(
<query>,
[
{ $set: { status: "Modified", comments: [ "$misc1", "$misc2" ] } },
{ $unset: [ "misc1", "misc2" ] }
]
...
)
For examples, see Update with Aggregation Pipeline.有关示例,请参阅使用聚合管道进行更新。
Capped Collections封顶集合
If an update operation changes the document size, the operation will fail.如果更新操作更改了文档大小,则该操作将失败。
Time Series Collections时间序列集合
The updateMany()
method is available for time series collections starting in MongoDB 5.1.updateMany()
方法可用于MongoDB 5.1中开始的时间序列集合。
Update commands must meet the following requirements:更新命令必须满足以下要求:
You can only match on the只能在metaField
field value.metaField
字段值上匹配。You can only modify the您只能修改metaField
field value.metaField
字段值。Your update document can only contain update operator expressions.更新文档只能包含更新运算符表达式。Your update command must not limit the number of documents to be updated.更新命令不得限制要更新的文档数。Set设置multi: true
or use theupdateMany()
method.multi:true
或使用updateMany()
方法。Your update command must not set upsert: true.您的更新命令不得设置upsert:true
。
Sharded Collections分片集合
For a 对于包含db.collection.updateMany()
operation that includes upsert: true
and is on a sharded collection, you must include the full shard key in the filter
.upsert:true
并且位于分片集合上的db.collection.updateMany()
操作,必须在filter
中包含完整的分片键。
Explainability解释能力
updateMany()
is not compatible with db.collection.explain()
.
Transactions事务
db.collection.updateMany()
can be used inside multi-document transactions.可以在多文档事务中使用。
In most cases, multi-document transaction incurs a greater performance cost over single document writes, and the availability of multi-document transactions should not be a replacement for effective schema design. 在大多数情况下,与单文档写入相比,多文档事务会产生更高的性能成本,并且多文档事务的可用性不应取代有效的模式设计。For many scenarios, the denormalized data model (embedded documents and arrays) will continue to be optimal for your data and use cases. 对于许多场景,非规范化数据模型(嵌入文档和数组)将继续是您的数据和用例的最佳选择。That is, for many scenarios, modeling your data appropriately will minimize the need for multi-document transactions.也就是说,对于许多场景,对数据进行适当建模将最大限度地减少对多文档事务的需求。
For additional transactions usage considerations (such as runtime limit and oplog size limit), see also Production Considerations.有关其他事务使用注意事项(如运行时限制和操作日志大小限制),请参阅生产注意事项。
Upsert within Transactions事务中的Upsert
Starting in MongoDB 4.4, you can create collections and indexes inside a multi-document transaction if the transaction is not a cross-shard write transaction.从MongoDB 4.4开始,如果多文档事务不是跨分片写入事务,则可以在该事务内创建集合和索引。
Specifically, in MongoDB 4.4 and greater, 具体来说,在MongoDB 4.4及更高版本中,具有db.collection.updateMany()
with upsert: true
can be run on an existing collection or a non-existing collection. upsert:true
的db.collection.updateMany()
可以在现有集合或不存在的集合上运行。If run on a non-existing collection, the operation creates the collection.如果在不存在的集合上运行,则该操作将创建该集合。
In MongoDB 4.2 and earlier, the operation must be run on an existing collection.在MongoDB 4.2及更早版本中,操作必须在现有集合上运行。
See also: 另请参阅:
Write Concerns and Transactions撰写关注事项和事务
Do not explicitly set the write concern for the operation if run in a transaction. 如果在事务中运行,请不要显式设置操作的写入关注。To use write concern with transactions, see Transactions and Write Concern.要在事务中使用写入关注,请参阅事务和写入关注。
Examples实例
Update Multiple Documents更新多个文档
The restaurant
collection contains the following documents:restaurant
集合包含以下文件:
{ "_id" : 1, "name" : "Central Perk Cafe", "violations" : 3 }
{ "_id" : 2, "name" : "Rock A Feller Bar and Grill", "violations" : 2 }
{ "_id" : 3, "name" : "Empire State Sub", "violations" : 5 }
{ "_id" : 4, "name" : "Pizza Rat's Pizzaria", "violations" : 8 }
The following operation updates all documents where 以下操作将更新violations
are greater than 4
and $set
a flag for review:violations
(违规次数)大于4
的所有文档,并$set
一个标志以供审查:
try {
db.restaurant.updateMany(
{ violations: { $gt: 4 } },
{ $set: { "Review" : true } }
);
} catch (e) {
print(e);
}
The operation returns:操作返回:
{ "acknowledged" : true, "matchedCount" : 2, "modifiedCount" : 2 }
The collection now contains the following documents:该集合现在包含以下文档:
{ "_id" : 1, "name" : "Central Perk Cafe", "violations" : 3 }
{ "_id" : 2, "name" : "Rock A Feller Bar and Grill", "violations" : 2 }
{ "_id" : 3, "name" : "Empire State Sub", "violations" : 5, "Review" : true }
{ "_id" : 4, "name" : "Pizza Rat's Pizzaria", "violations" : 8, "Review" : true }
If no matches were found, the operation instead returns:如果未找到匹配项,则操作将返回:
{ "acknowledged" : true, "matchedCount" : 0, "modifiedCount" : 0 }
Setting 如果未找到匹配项,则设置upsert: true
would insert a document if no match was found.upsert: true
将插入文档。
Update with Aggregation Pipeline使用聚合管道更新
Starting in MongoDB 4.2, the 从MongoDB 4.2开始,db.collection.updateMany()
can use an aggregation pipeline for the update. The pipeline can consist of the following stages:db.collection.updateMany()
可以使用聚合管道进行更新。管道可由以下阶段组成:
$addFields
and its alias及其别名$set
$project
and its alias及其别名$unset
$replaceRoot
and its alias及其别名$replaceWith
.
Using the aggregation pipeline allows for a more expressive update statement, such as expressing conditional updates based on current field values or updating one field using the value of another field(s).使用聚合管道可以实现更具表达力的更新语句,例如基于当前字段值表达条件更新,或者使用另一个字段的值更新一个字段。
Example 1: Update with Aggregation Pipeline Using Existing Fields示例1:使用现有字段使用聚合管道进行更新
The following examples uses the aggregation pipeline to modify a field using the values of the other fields in the document.以下示例使用聚合管道使用文档中其他字段的值修改字段。
Create a 使用以下文档创建students
collection with the following documents:students
集合:
db.students.insertMany( [
{ "_id" : 1, "student" : "Skye", "points" : 75, "commentsSemester1" : "great at math", "commentsSemester2" : "loses temper", "lastUpdate" : ISODate("2019-01-01T00:00:00Z") },
{ "_id" : 2, "students" : "Elizabeth", "points" : 60, "commentsSemester1" : "well behaved", "commentsSemester2" : "needs improvement", "lastUpdate" : ISODate("2019-01-01T00:00:00Z") }
] )
Assume that instead of separate 假设您不想将commentsSemester1
and commentsSemester2
fields, you want to gather these into a new comments
field. commentsSemester1
和commentsSomester2
字段分开,而是想将它们聚集到一个新的comments
字段中。The following update operation uses an aggregation pipeline to:
add the new添加新的comments
field and set thelastUpdate
field.comments
字段并设置lastUpdate
字段。remove the删除集合中所有文档的commentsSemester1
andcommentsSemester2
fields for all documents in the collection.commentsSemester1
和commentsSomester2
字段。
db.students.updateMany(
{ },
[
{ $set: { comments: [ "$commentsSemester1", "$commentsSemester2" ], lastUpdate: "$$NOW" } },
{ $unset: [ "commentsSemester1", "commentsSemester2" ] }
]
)
First Stage第一阶段-
creates a new array field创建一个新的数组字段comments
whose elements are the current content of thecommentsSemester1
andcommentsSemester2
fields andcomments
,其元素是commentsSemester1
和commentsSomester2
字段的当前内容sets the field将字段lastUpdate
to the value of the aggregation variableNOW
.lastUpdate
设置为聚合变量NOW
的值。The aggregation variable聚合变量NOW
resolves to the current datetime value and remains the same throughout the pipeline.NOW
解析为当前日期时间值,并在整个管道中保持不变。To access aggregation variables, prefix the variable with double dollar signs要访问聚合变量,请在变量前面加上双美元符号$$
and enclose in quotes.$$
并用引号括起来。
Second Stage第二阶段The$unset
stage removes thecommentsSemester1
andcommentsSemester2
fields.$unset
阶段删除commentsSemester1
和commentsSemoster2
字段。
After the command, the collection contains the following documents:命令之后,集合包含以下文档:
{ "_id" : 1, "student" : "Skye", "status" : "Modified", "points" : 75, "lastUpdate" : ISODate("2020-01-23T05:11:45.784Z"), "comments" : [ "great at math", "loses temper" ] }
{ "_id" : 2, "student" : "Elizabeth", "status" : "Modified", "points" : 60, "lastUpdate" : ISODate("2020-01-23T05:11:45.784Z"), "comments" : [ "well behaved", "needs improvement" ] }
Example 2: Update with Aggregation Pipeline Using Existing Fields Conditionally示例2:有条件地使用现有字段使用聚合管道进行更新
The aggregation pipeline allows the update to perform conditional updates based on the current field values as well as use current field values to calculate a separate field value.聚合管道允许更新基于当前字段值执行条件更新,并使用当前字段值计算单独的字段值。
For example, create a 例如,使用以下文档创建students3
collection with the following documents:students3
集合:
db.students3.insertMany( [
{ "_id" : 1, "tests" : [ 95, 92, 90 ], "lastUpdate" : ISODate("2019-01-01T00:00:00Z") },
{ "_id" : 2, "tests" : [ 94, 88, 90 ], "lastUpdate" : ISODate("2019-01-01T00:00:00Z") },
{ "_id" : 3, "tests" : [ 70, 75, 82 ], "lastUpdate" : ISODate("2019-01-01T00:00:00Z") }
] )
Using an aggregation pipeline, you can update the documents with the calculated grade average and letter grade.使用聚合管道,可以使用计算出的平均成绩和字母成绩更新文档。
db.students3.updateMany(
{ },
[
{ $set: { average : { $trunc: [ { $avg: "$tests" }, 0 ] } , lastUpdate: "$$NOW" } },
{ $set: { grade: { $switch: {
branches: [
{ case: { $gte: [ "$average", 90 ] }, then: "A" },
{ case: { $gte: [ "$average", 80 ] }, then: "B" },
{ case: { $gte: [ "$average", 70 ] }, then: "C" },
{ case: { $gte: [ "$average", 60 ] }, then: "D" }
],
default: "F"
} } } }
]
)
First Stage第一阶段-
calculates a new field基于average
based on the average of thetests
field.tests
字段的平均值来计算新的字段average
。See有关$avg
for more information on the$avg
aggregation operator and$trunc
for more information on the$trunc
truncate aggregation operator.$avg
聚合运算符的详细信息,请参阅$avg
;有关$trunc
截断聚合运算符的更多信息,请参阅$trunc
。sets the field将字段lastUpdate
to the value of the aggregation variableNOW
.lastUpdate
设置为聚合变量NOW
的值。The aggregation variable聚合变量NOW
resolves to the current datetime value and remains the same throughout the pipeline.NOW
解析为当前日期时间值,并在整个管道中保持不变。To access aggregation variables, prefix the variable with double dollar signs要访问聚合变量,请在变量前面加上双美元符号$$
and enclose in quotes.$$
并用引号括起来。
Second Stage第二阶段The$set
stage calculates a new fieldgrade
based on theaverage
field calculated in the previous stage.$set
阶段根据上一阶段中计算的average
字段来计算新的字段grade
。See有关$switch
for more information on the$switch
aggregation operator.$switch
聚合运算符的详细信息,请参阅$switch
。
After the command, the collection contains the following documents:命令之后,集合包含以下文档:
{ "_id" : 1, "tests" : [ 95, 92, 90 ], "lastUpdate" : ISODate("2020-01-24T17:31:01.670Z"), "average" : 92, "grade" : "A" }
{ "_id" : 2, "tests" : [ 94, 88, 90 ], "lastUpdate" : ISODate("2020-01-24T17:31:01.670Z"), "average" : 90, "grade" : "A" }
{ "_id" : 3, "tests" : [ 70, 75, 82 ], "lastUpdate" : ISODate("2020-01-24T17:31:01.670Z"), "average" : 75, "grade" : "C" }
See also: 另请参阅:
Update Multiple Documents with Upsert使用Upsert更新多个文档
The inspectors
collection contains the following documents:inspectors
集合包含以下文件:
{ "_id" : 92412, "inspector" : "F. Drebin", "Sector" : 1, "Patrolling" : true },
{ "_id" : 92413, "inspector" : "J. Clouseau", "Sector" : 2, "Patrolling" : false },
{ "_id" : 92414, "inspector" : "J. Clouseau", "Sector" : 3, "Patrolling" : true },
{ "_id" : 92415, "inspector" : "R. Coltrane", "Sector" : 3, "Patrolling" : false }
The following operation updates all documents with 以下操作更新Sector
greater than 4 and inspector
equal to "R. Coltrane"
:Sector
大于4
且inspector
等于"R. Coltrane"
的所有文档:
try {
db.inspectors.updateMany(
{ "Sector" : { $gt : 4 }, "inspector" : "R. Coltrane" },
{ $set: { "Patrolling" : false } },
{ upsert: true }
);
} catch (e) {
print(e);
}
The operation returns:操作返回:
{
"acknowledged" : true,
"matchedCount" : 0,
"modifiedCount" : 0,
"upsertedId" : ObjectId("56fc5dcb39ee682bdc609b02")
}
The collection now contains the following documents:该集合现在包含以下文档:
{ "_id" : 92412, "inspector" : "F. Drebin", "Sector" : 1, "Patrolling" : true },
{ "_id" : 92413, "inspector" : "J. Clouseau", "Sector" : 2, "Patrolling" : false },
{ "_id" : 92414, "inspector" : "J. Clouseau", "Sector" : 3, "Patrolling" : true },
{ "_id" : 92415, "inspector" : "R. Coltrane", "Sector" : 3, "Patrolling" : false },
{ "_id" : ObjectId("56fc5dcb39ee682bdc609b02"), "inspector" : "R. Coltrane", "Patrolling" : false }
Since no documents matched the filter, and 由于没有文档与筛选器匹配,并且upsert
was true
, updateMany()
inserted the document with a generated _id
, the equality conditions from the filter
, and the update
modifiers.upsert
为true
,updateMany()
插入了具有生成的_id
、filter
中的相等条件和update
修饰符的文档。
Update with Write Concern带写入关注的更新
Given a three member replica set, the following operation specifies a 给定一个由三个成员组成的复制集,以下操作指定w
of majority
and wtimeout
of 100
:w
为majority
,wtimeout
为100
:
try {
db.restaurant.updateMany(
{ "name" : "Pizza Rat's Pizzaria" },
{ $inc: { "violations" : 3}, $set: { "Closed" : true } },
{ w: "majority", wtimeout: 100 }
);
} catch (e) {
print(e);
}
If the acknowledgement takes longer than the 如果确认花费的时间超过wtimeout
limit, the following exception is thrown:wtimeout
限制,则引发以下异常:
Changed in version 4.4.4.4版更改。
WriteConcernError({
"code" : 64,
"errmsg" : "waiting for replication timed out",
"errInfo" : {
"wtimeout" : true,
"writeConcern" : {
"w" : "majority",
"wtimeout" : 100,
"provenance" : "getLastErrorDefaults"
}
}
})
The following table explains the possible values of 下表解释了errInfo.writeConcern.provenance
:errInfo.writeConcern.provenance
出处的可能值:
clientSupplied | |
customDefault | setDefaultRWConcern .setDefaultRWConcern 。 |
getLastErrorDefaults | settings.getLastErrorDefaults field.settings.getLastErrorDefaults 字段。 |
implicitDefault |
Specify Collation指定排序规则
collation
allows users to specify language-specific rules for string comparison, such as rules for lettercase and accent marks.允许用户为字符串比较指定特定于语言的规则,例如字母大小写和重音标记的规则。
A collection 集合myColl
has the following documents:myColl
包含以下文档:
{ _id: 1, category: "café", status: "A" }
{ _id: 2, category: "cafe", status: "a" }
{ _id: 3, category: "cafE", status: "a" }
The following operation includes the collation option:以下操作包括collation
选项:
db.myColl.updateMany(
{ category: "cafe" },
{ $set: { status: "Updated" } },
{ collation: { locale: "fr", strength: 1 } }
);
Specify arrayFilters
for an Array Update Operations为数组更新操作指定arrayFilters
arrayFilters
for an Array Update OperationsStarting in MongoDB 3.6, when updating an array field, you can specify 从MongoDB 3.6开始,在更新数组字段时,可以指定arrayFilters
that determine which array elements to update.arrayFilters
来确定要更新的数组元素。
Update Elements Match arrayFilters
Criteria更新匹配arrayFilters
条件的元素
arrayFilters
CriteriaCreate a collection 使用以下文档创建students
with the following documents:students
集合:
db.students.insertMany( [
{ "_id" : 1, "grades" : [ 95, 92, 90 ] },
{ "_id" : 2, "grades" : [ 98, 100, 102 ] },
{ "_id" : 3, "grades" : [ 95, 110, 100 ] }
] )
To update all elements that are greater than or equal to 要更新100
in the grades
array, use the filtered positional operator $[<identifier>]
with the arrayFilters
option:grades
数组中大于或等于100
的所有元素,请将已筛选的位置运算符$[<identifier>]
与arrayFilters
选项一起使用:
db.students.updateMany(
{ grades: { $gte: 100 } },
{ $set: { "grades.$[element]" : 100 } },
{ arrayFilters: [ { "element": { $gte: 100 } } ] }
)
After the operation, the collection contains the following documents:操作后,集合包含以下文档:
{ "_id" : 1, "grades" : [ 95, 92, 90 ] }
{ "_id" : 2, "grades" : [ 98, 100, 100 ] }
{ "_id" : 3, "grades" : [ 95, 100, 100 ] }
Update Specific Elements of an Array of Documents更新文档数组的特定元素
Create a collection 使用以下文档创建集合students2
with the following documents:students2
:
db.students2.insertMany( [
{
"_id" : 1,
"grades" : [
{ "grade" : 80, "mean" : 75, "std" : 6 },
{ "grade" : 85, "mean" : 90, "std" : 4 },
{ "grade" : 85, "mean" : 85, "std" : 6 }
]
},
{
"_id" : 2,
"grades" : [
{ "grade" : 90, "mean" : 75, "std" : 6 },
{ "grade" : 87, "mean" : 90, "std" : 3 },
{ "grade" : 85, "mean" : 85, "std" : 4 }
]
}
] )
To modify the value of the 要修改mean
field for all elements in the grades
array where the grade is greater than or equal to 85
, use the filtered positional operator $[<identifier>]
with the arrayFilters
:grades
数组中等级大于或等于85
的所有元素的mean
字段值,请将筛选后的位置运算符$[<identifier>]
与arrayFilters
一起使用:
db.students2.updateMany(
{ },
{ $set: { "grades.$[elem].mean" : 100 } },
{ arrayFilters: [ { "elem.grade": { $gte: 85 } } ] }
)
After the operation, the collection has the following documents:操作后,集合具有以下文档:
{
"_id" : 1,
"grades" : [
{ "grade" : 80, "mean" : 75, "std" : 6 },
{ "grade" : 85, "mean" : 100, "std" : 4 },
{ "grade" : 85, "mean" : 100, "std" : 6 }
]
}
{
"_id" : 2,
"grades" : [
{ "grade" : 90, "mean" : 100, "std" : 6 },
{ "grade" : 87, "mean" : 100, "std" : 3 },
{ "grade" : 85, "mean" : 100, "std" : 4 }
]
}
Specify hint
for Update Operations指定更新操作的hint
hint
for Update OperationsNew in version 4.2.1. 4.2.1版新增。
Create a sample 使用以下文档创建示例students
collection with the following documents:students
集合:
db.students.insertMany( [
{ "_id" : 1, "student" : "Richard", "grade" : "F", "points" : 0, "comments1" : null, "comments2" : null },
{ "_id" : 2, "student" : "Jane", "grade" : "A", "points" : 60, "comments1" : "well behaved", "comments2" : "fantastic student" },
{ "_id" : 3, "student" : "Ronan", "grade" : "F", "points" : 0, "comments1" : null, "comments2" : null },
{ "_id" : 4, "student" : "Noah", "grade" : "D", "points" : 20, "comments1" : "needs improvement", "comments2" : null },
{ "_id" : 5, "student" : "Adam", "grade" : "F", "points" : 0, "comments1" : null, "comments2" : null },
{ "_id" : 6, "student" : "Henry", "grade" : "A", "points" : 86, "comments1" : "fantastic student", "comments2" : "well behaved" }
] )
Create the following indexes on the collection:在集合上创建以下索引:
db.students.createIndex( { grade: 1 } )
The following update operation explicitly hints to use the index 以下更新操作明确提示使用索引{ grade: 1 }
:{ grade: 1 }
:
If you specify an index that does not exist, the operation errors.如果指定的索引不存在,则操作将出错。
db.students.updateMany(
{ "points": { $lte: 20 }, "grade": "F" },
{ $set: { "comments1": "failed class" } },
{ hint: { grade: 1 } }
)
The update command returns the following:update命令返回以下内容:
{ "acknowledged" : true, "matchedCount" : 3, "modifiedCount" : 3 }
To see the index used, run 要查看使用的索引,请对操作运行explain
on the operation:explain
:
db.students.explain().updateMany(
{ "points": { $lte: 20 }, "grade": "F" },
{ $set: { "comments1": "failed class" } },
{ multi: true, hint: { grade: 1 } }
)
User Roles and Document Updates用户角色和文档更新
Starting in MongoDB 7.0, you can use the new 从MongoDB 7.0开始,您可以使用新的USER_ROLES
system variable to return user roles.USER_ROLES
系统变量来返回用户角色。
The example in this section shows updates to fields in a collection containing medical information. 本节中的示例显示了对包含医疗信息的集合中的字段的更新。The example reads the current user roles from the 此示例从USER_ROLES
system variable and only performs the updates if the user has a specific role.USER_ROLES
系统变量中读取当前用户角色,并且仅当用户具有特定角色时才执行更新。
To use a system variable, add 要使用系统变量,请在变量名的开头添加$$
to the start of the variable name. Specify the USER_ROLES
system variable as $$USER_ROLES
.$$
。将USER_ROLES
系统变量指定为$$USER_ROLES
。
The example creates these users:该示例创建了以下用户:
James
with aBilling
role.James
具有Billing
角色。Michelle
with aProvider
role.Michelle
具有Provider
角色。
Perform the following steps to create the roles, users, and collection:执行以下步骤以创建角色、用户和集合:
Create the roles创建角色
Create roles named 创建具有所需权限和资源的名为Billing
and Provider
with the required privileges and resources.Billing
和Provider
的角色。
Run:
db.createRole( { role: "Billing", privileges: [ { resource: { db: "test",
collection: "medicalView" }, actions: [ "find" ] } ], roles: [ ] } )
db.createRole( { role: "Provider", privileges: [ { resource: { db: "test",
collection: "medicalView" }, actions: [ "find" ] } ], roles: [ ] } )
Log in as as 以Michelle
, who has the Provider
role, and perform an update:Michelle
的身份登录,Michelle
具有Provider
角色,并执行更新:
The previous example uses 上一个示例使用$setIntersection
to return documents where the intersection between the "Provider"
string and the user roles from $$USER_ROLES.role
is not empty. $setIntersection
返回"Provider"
字符串与$$USER_ROLES.role
中的用户角色之间的交集不为空的文档。Michelle
has the Provider
role, so the update is performed.Michelle
具有Provider
角色,因此执行更新。
Next, log in as as 接下来,以James
, who does not have the Provider
role, and attempt to perform the same update:James
的身份登录,James没有提供程序角色,并尝试执行相同的更新:
Attempt to perform update尝试执行更新
Run:运行:
// Attempt to update many documents
db.medical.updateMany(
// User must have the Provider role to perform the update
{ $expr: { $ne: [ {
$setIntersection: [ [ "Provider" ], "$$USER_ROLES.role" ] }, []
] } },
// Update diagnosisCode
{ $set: { diagnosisCode: "ACH 02"} }
)
The previous example does not update any documents.上一个示例不更新任何文档。