爲了將近2萬條數據從一個庫提取到另外一個庫中,恰好MongoDB支持導出的數據可以是csv文件和json文件,所以下面介紹下MongoDB mongoexport和mongoimport方法;
一、導出工具mongoexport 簡介,通過幫助先了解下mongoexport的功能參數
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[root@iZ2ze4b308vd83fulq9n7iZ ~]# mongoexport --help
Usage:
mongoexport <options>
Export data from MongoDB in CSV or JSON format.
See http://docs.mongodb.org/manual/reference/program/mongoexport/ for more information.
general options:
--help print usage
--version print the tool version and exit
verbosity options:
-v, --verbose more detailed log output (include multiple times for more verbosity, e.g. -vvvvv)
--quiet hide all log output
connection options:
-h, --host= mongodb host to connect to (setname/host1,host2 for replica sets)
--port= server port (can also use --host hostname:port)
authentication options:
-u, --username= username for authentication
-p, --password= password for authentication
--authenticationDatabase= database that holds the user's credentials
--authenticationMechanism= authentication mechanism to use
namespace options:
-d, --db= database to use
-c, --collection= collection to use
output options:
-f, --fields= comma separated list of field names (required for exporting CSV) e.g. -f "name,age"
--fieldFile= file with field names - 1 per line
--type= the output format, either json or csv (defaults to 'json')
-o, --out= output file; if not specified, stdout is used
--jsonArray output to a JSON array rather than one object per line
--pretty output JSON formatted to be human-readable
querying options:
-q, --query= query filter, as a JSON string, e.g., '{x:{$gt:1}}'
-k, --slaveOk allow secondary reads if available (default true)
--forceTableScan force a table scan (do not use $snapshot)
--skip= number of documents to skip
--limit= limit the number of documents to export
--sort= sort order, as a JSON string, e.g. '{x:1}'
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關鍵參數說明:
-h,--host :代表遠程連接的數據庫地址,默認連接本地Mongo數據庫;
--port:代表遠程連接的數據庫的端口,默認連接的遠程端口27017;
-u,--username:代表連接遠程數據庫的賬號,如果設置數據庫的認證,需要指定用戶賬號;
-p,--password:代表連接數據庫的賬號對應的密碼;
-d,--db:代表連接的數據庫;
-c,--collection:代表連接數據庫中的集合;
-f, --fields:代表集合中的字段,可以根據設置選擇導出的字段;
--type:代表導出輸出的文件類型,包括csv和json文件;
-o, --out:代表導出的文件名;
-q, --query:代表查詢條件;
--skip:跳過指定數量的數據;
--limit:讀取指定數量的數據記錄;
--sort:對數據進行排序,可以通過參數指定排序的字段,並使用 1 和 -1 來指定排序的方式,其中 1 爲升序排列,而-1是用於降序排列,如sort({KEY:1})。
注意:
當查詢時同時使用sort,skip,limit,無論位置先後,最先執行順序 sort再skip再limit。
實例:
首先查看下數據庫中的數據一共多少條,通過的命令的方式查看下我們要導出的數據信息
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> db.bike.find().count()
16878865
> db.bike.find({"source":"ofo"}).limit(1)
{ "_id" : ObjectId("59e8c27804390e04a063159d"), "lat" : 39.9571954199, "bikeId" : "pgdAVg", "current_time" : "2017-10-19 23:19:19", "source" : "ofo", "lng" : 116.3926501736 }
>
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如何通過mongoexport導出"bikeId" : "pgdAVg"的數據,我導出了json和csv兩種類型的數據;
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#導出類型爲json,數據庫:mapdb,集合:bike 字段:bikeId,lat,lng,current_time,source ,條件爲source字段爲ofo第一條數據
mongoexport --port 27030 -u sa -p Expressin@0618 -d mapdb -c bike -f bikeId,lat,lng,current_time,source --type=json -o bike.json --query='{"source":"ofo"}' --limit=1
#導出類型爲csv,數據庫:mapdb,集合:bike 字段:bikeId,lat,lng,current_time,source ,條件爲source字段爲ofo第一條數據
mongoexport --port 27030 -u sa -p Expressin@0618 -d mapdb -c bike -f bikeId,lat,lng,current_time,source --type=csv -o bike.csv --query='{"source":"ofo"}' --limit=1
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查看下結果是否是我們兩種不同的結果集;
1.導出csv類型;
2.導出json類型;
二、導入工具mongoimport 簡介,通過幫助先了解下mongoimport的功能參數
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[root@iZ2ze4b308vd83fulq9n7iZ ~]# mongoimport --help
Usage:
mongoimport <options> <file>
Import CSV, TSV or JSON data into MongoDB. If no file is provided, mongoimport reads from stdin.
See http://docs.mongodb.org/manual/reference/program/mongoimport/ for more information.
general options:
--help print usage
--version print the tool version and exit
verbosity options:
-v, --verbose more detailed log output (include multiple times for more verbosity, e.g. -vvvvv)
--quiet hide all log output
connection options:
-h, --host= mongodb host to connect to (setname/host1,host2 for replica sets)
--port= server port (can also use --host hostname:port)
authentication options:
-u, --username= username for authentication
-p, --password= password for authentication
--authenticationDatabase= database that holds the user's credentials
--authenticationMechanism= authentication mechanism to use
namespace options:
-d, --db= database to use
-c, --collection= collection to use
input options:
-f, --fields= comma separated list of field names, e.g. -f name,age
--fieldFile= file with field names - 1 per line
--file= file to import from; if not specified, stdin is used
--headerline use first line in input source as the field list (CSV and TSV only)
--jsonArray treat input source as a JSON array
--type= input format to import: json, csv, or tsv (defaults to 'json')
ingest options:
--drop drop collection before inserting documents
--ignoreBlanks ignore fields with empty values in CSV and TSV
--maintainInsertionOrder insert documents in the order of their appearance in the input source
-j, --numInsertionWorkers= number of insert operations to run concurrently (defaults to 1)
--stopOnError stop importing at first insert/upsert error
--upsert insert or update objects that already exist
--upsertFields= comma-separated fields for the query part of the upsert
--writeConcern= write concern options e.g. --writeConcern majority, --writeConcern '{w: 3, wtimeout: 500, fsync: true, j: true}' (defaults to 'majority')
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關鍵參數說明:
h,--host :代表遠程連接的數據庫地址,默認連接本地Mongo數據庫;
--port:代表遠程連接的數據庫的端口,默認連接的遠程端口27017;
-u,--username:代表連接遠程數據庫的賬號,如果設置數據庫的認證,需要指定用戶賬號;
-p,--password:代表連接數據庫的賬號對應的密碼;
-d,--db:代表連接的數據庫;
-c,--collection:代表連接數據庫中的集合;
-f, --fields:代表導入集合中的字段;
--type:代表導入的文件類型,包括csv和json,tsv文件,默認json格式;
--file:導入的文件名稱
--headerline:導入csv文件時,指明第一行是列名,不需要導入;
實例演示:
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#首先查看集合中的數據
> db.bike_bak.find()
{ "_id" : ObjectId("59e8c27804390e04a063159d"), "lat" : 39.9571954199, "bikeId" : "pgdAVg", "current_time" : "2017-10-19 23:19:19", "source" : "ofo", "lng" : 116.3926501736 }
#刪除集合中的數據
> db.bike_bak.remove({"bikeId" : "pgdAVg"})
WriteResult({ "nRemoved" : 1 })
#查看集合是否包含數據
> db.bike_bak.find()
>
#導入數據
[root@iZ2ze4b308vd83fulq9n7iZ ~]# mongoimport --port 27030 -u sa -p Expressin@0618 -d mapdb -c bike_bak --type=json --file bike.csv
2017-10-25T11:59:51.020+0800 connected to: localhost:27030
2017-10-25T11:59:51.030+0800 imported 1 document
#檢查數據是否導入成功
> db.bike_bak.find()
{ "_id" : ObjectId("59e8c27804390e04a063159d"), "bikeId" : "pgdAVg", "current_time" : "2017-10-19 23:19:19", "lat" : 39.9571954199, "lng" : 116.3926501736, "source" : "ofo" }
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完畢
實踐出真知,祝君成功!