官网上说不能用来匹配一个范围内的元素,如果想找$size<5之类的,他们建议创建一个字段来保存元素的数量。 You cannot use $size to find a range of sizes (for example: arrays with more than 1 element). If you need to query for a range, create an extra size field that you increment when you ...
address:"test2"})db.order.insert({orderId:1,orderCode:"order001",customerCode:1,price:200})db.order.insert({orderId:2,orderCode:"order002",customerCode:2,price:400})db.orderItem.insert({itemId:1,productName:
allowDiskUse() - allow using disk in completing the query Cursor methods .toArray() - iterates through docs and returns an array of the results .forEach(<func>) .map(<func>) .hasNext() .next() .close() .objsLeftInBatch() - returns count of docs left in current batch (when ...
MongoDB Manual: code examples for query operations on array fields. Learn how to query an array and an array element or field, query on the array field as a whole, query if a field is in an array, and query by array size.
2. Query an Array 查询数组 本页面提供了使用 mongo shell 中的 db.collection.find ()方法对数组字段进行查询操作的示例。本页上的示例使用库存集合。要填充库存集合,请运行以下命令: db.inventory.insertMany([{ item:"journal", qty:25, tags: ["blank","red"],dim_cm:[14,21] }, ...
explain.queryPlanner.winningPlan.isMultiKey是否是Multikey,此处返回是false,如果索引建立在array上,此处将是true。 explain.queryPlanner.winningPlan.direction:此query的查询顺序,此处是forward,如果用了.sort({modify_time:-1})将显示backward。 explain.queryPlanner.winningPlan.indexBounds:winningplan所扫描的索引...
Learn about the query and projection operators in MongoDB. These query selectors, projection operators, and miscellaneous operators help with advanced querying and projection.
我试图在另一个数组字段上使用$elemMatch和$in操作符更新数组中的对象。 我的查询如下所示: var query = {array:{$in: ['second']},objectList: {$elemMatch: {toMatch: {$exists: true}}} }; db.foo.update(query, {$set: {'objectList.$.toChange':10}}, {multi: true}) ...
{item:"postcard",qty:45,tags: ["blue"],dim_cm: [10,15.25] } ]); Match an Array To specify equality condition on an array, use the query document{ <field>: <value> }where<value>is the exact array to match, including the order of the elements. ...
/** * 更新查询结果的第一个值 * mongoTemplate.update() 不建议用 * 方法1更新最慢,方法2和方法3差不多 * 方法1 : UpdateResult updateFirst(Query query, Update update, Class<?> entityClass) * 方法2 : UpdateResult updateFirst(Query query, Update update, String collectionName) * 方法3 : Upda...