xloc : x->nextChild; //压入上面弹出的最右边的键值,该键值为当前up(bucket)中最大值 if ( ! up->_pushBack(r, k, ordering, keepLoc) ) { // 当前 bucket 已满,则新创建一个addBucket DiskLoc n = BtreeBucket::addBucket(idx); up->tempNext() = n; u
数组表达式运算符 https://docs.mongodb.com/v3.6/reference/operator/aggregation/#array-expression-operators 布尔表达式运算符 https://docs.mongodb.com/v3.6/reference/operator/aggregation/#boolean-expression-operators 布尔表达式将其参数表达式评估为布尔值,并返回布尔值作为结果。 除了false布尔值,布尔表达式为fa...
You cannot use $size to find a range of sizes (for example: arrays with more than 1 element). If you need to query for a range, create an extra size field that you increment when you add elements. 7)$exists $exists用来判断一个元素是否存在: 如: db.things.find( { a : { $exists ...
MongoDB shell version v3.6.3connecting to:mongodb://127.0.0.1:27017MongoDB server version:3.6.3Server has startup warnings:2019-07-01T15:40:20.741+0800ICONTROL[initandlisten]2019-07-01T15:40:20.741+0800ICONTROL[initandlisten]**WARNING:Access control is not enabledforthe database.2019-07-01T15...
// 元数据相关的锁 /** Resource type used for locking general resources not related to the storage...Used for array size allocations, etc. Always insert new lock modes * above this entry. */ ...(partitionedLock); lock->partitions.push_back(partition); partitionedLock->newRequest(request); ...
(aggregation) $not (aggregation) $objectToArray (aggregation) $or (aggregation) $pow (aggregation) $push (aggregation) $radiansToDegrees (aggregation) $range (aggregation) $reduce (aggregation) $regexFind (aggregation) $regexFindAll (aggregation) $regexMatch (aggregation) $replaceOne (aggregation) ...
1.$push: 向数组字段中添加元素(不去重) 2.格式: {$push: {<field>:<value1>, ...}} // 可以添加重复元素 db.users.update({name:'z3'},...1. $和$[]数组更新操作符 $: 更新数组中满足条件的特定元素 格式: db.<collection>.update( { <array field>:<query selector> } { <update operato...
request[‘ebay_results’] = ebay_results_array collection.save(request) 在这个例子中,request是彼得的文档,ebay_results是键,ebay_result_array包含来自易贝的结果。第二行保存更改。当他将来访问这个文档时,他将得到与以前完全相同格式的易贝结果。他不需要任何 SQL 他不需要执行任何转换;他也不需要创建任何新...
['hash'] = {['$push'] = '$hash'}, ---“hash”是目标数据中的字段key ['name'] = {['$push'] = '$name'}, ---“name”是目标数据中的字段key ['image'] = {['$push'] = '$pgcrImage'}, ---“pgcrImage”是目标数据中的字段key ['aLv'] = {['$push'] = '$activityLevel'}...
$mongo = new MongoDB\Driver\Manager(); $query = new MongoDB\Driver\Query(array( '_id'=>$id )); $result = $mongo->executeQuery('db.collection', $query)->toArray(); // 返回的$result是一个对象,需要 toArray() 转换成数组。