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mongoexport¶
Synopsis¶
mongoexport is a utility that produces a JSON or CSV export of data stored in a MongoDB instance. See the 导入导出MongoDB数据 document for a more in depth usage overview, and the mongoimport document for more information regarding the mongoimport utility, which provides the inverse “importing” capability.
Considerations¶
Do not use mongoimport and mongoexport for full-scale production backups because they may not reliably capture data type information. Use mongodump and mongorestore as described in MongoDB备份方案 for this kind of functionality.
Options¶
- mongoexport¶
- mongoexport¶
- --help¶
Returns information on the options and use of mongoexport.
- --verbose, -v¶
Increases the amount of internal reporting returned on standard output or in log files. Increase the verbosity with the -v form by including the option multiple times, (e.g. -vvvvv.)
- --quiet¶
Runs the mongoexport in a quiet mode that attempts to limit the amount of output.
This option suppresses:
- output from database commands
- replication activity
- connection accepted events
- connection closed events
- --version¶
Returns the mongoexport release number.
- --host <hostname><:port>, -h¶
Default: localhost:27017
Specifies a resolvable hostname for the mongod to which to connect. By default, the mongoexport attempts to connect to a MongoDB instance running on the localhost on port number 27017.
To connect to a replica set, specify the replica set name and a seed list of set members. Use the following form:
<replSetName>/<hostname1><:port>,<hostname2><:port>,<...>
You can always connect directly to a single MongoDB instance by specifying the host and port number directly.
- --port <port>¶
Default: 27017
Specifies the TCP port on which the MongoDB instance listens for client connections.
- --ipv6¶
Enables IPv6 support and allows the mongoexport to connect to the MongoDB instance using an IPv6 network. All MongoDB programs and processes disable IPv6 support by default.
- --ssl¶
2.6 新版功能.
Enables connection to a mongod or mongos that has SSL support enabled.
The default distribution of MongoDB does not contain support for SSL. For more information on MongoDB and SSL, see Configure mongod and mongos for SSL.
- --sslCAFile <filename>¶
2.6 新版功能.
Specifies the .pem file that contains the root certificate chain from the Certificate Authority. Specify the file name of the .pem file using relative or absolute paths.
The default distribution of MongoDB does not contain support for SSL. For more information on MongoDB and SSL, see Configure mongod and mongos for SSL.
警告
If the mongo shell or any other tool that connects to mongos or mongod is run without --sslCAFile, it will not attempt to validate server certificates. This results in vulnerability to expired mongod and mongos certificates as well as to foreign processes posing as valid mongod or mongos instances. Ensure that you always specify the CA file against which server certificates should be validated in cases where intrusion is a possibility.
- --sslPEMKeyFile <filename>¶
2.6 新版功能.
Specifies the .pem file that contains both the SSL certificate and key. Specify the file name of the .pem file using relative or absolute paths.
This option is required when using the --ssl option to connect to a mongod or mongos that has CAFile enabled without weakCertificateValidation.
The default distribution of MongoDB does not contain support for SSL. For more information on MongoDB and SSL, see Configure mongod and mongos for SSL.
- --sslPEMKeyPassword <value>¶
2.6 新版功能.
Specifies the password to de-crypt the certificate-key file (i.e. --sslPEMKeyFile). Use the --sslPEMKeyPassword option only if the certificate-key file is encrypted. In all cases, the mongoexport will redact the password from all logging and reporting output.
If the private key in the PEM file is encrypted and you do not specify the --sslPEMKeyPassword option, the mongoexport will prompt for a passphrase. See SSL Certificate Passphrase.
The default distribution of MongoDB does not contain support for SSL. For more information on MongoDB and SSL, see Configure mongod and mongos for SSL.
- --sslCRLFile <filename>¶
2.6 新版功能.
Specifies the .pem file that contains the Certificate Revocation List. Specify the file name of the .pem file using relative or absolute paths.
The default distribution of MongoDB does not contain support for SSL. For more information on MongoDB and SSL, see Configure mongod and mongos for SSL.
- --sslAllowInvalidCertificates¶
2.6 新版功能.
Bypasses the validation checks for server certificates and allows the use of invalid certificates. When using the allowInvalidCertificates setting, MongoDB logs as a warning the use of the invalid certificate.
The default distribution of MongoDB does not contain support for SSL. For more information on MongoDB and SSL, see Configure mongod and mongos for SSL.
- --sslFIPSMode¶
2.6 新版功能.
Directs the mongoexport to use the FIPS mode of the installed OpenSSL library. Your system must have a FIPS compliant OpenSSL library to use the --sslFIPSMode option.
The default distribution of MongoDB does not contain support for SSL. For more information on MongoDB and SSL, see Configure mongod and mongos for SSL.
- --username <username>, -u¶
Specifies a username with which to authenticate to a MongoDB database that uses authentication. Use in conjunction with the --password and --authenticationDatabase options.
- --password <password>, -p¶
Specifies a password with which to authenticate to a MongoDB database that uses authentication. Use in conjunction with the --username and --authenticationDatabase options.
- --authenticationDatabase <dbname>¶
2.4 新版功能.
Specifies the database that holds the user’s credentials. If you do not specify an authentication database, the mongoexport assumes that the database specified as the argument to the --db option holds the user’s credentials.
- --authenticationMechanism <name>¶
Default: MONGODB-CR
2.4 新版功能.
在 2.6 版更改: Added support for the PLAIN and MONGODB-X509 authentication mechanisms.
Specifies the authentication mechanism the mongoexport instance uses to authenticate to the mongod or mongos.
Value Description MONGODB-CR MongoDB challenge/response authentication. MONGODB-X509 MongoDB SSL certificate authentication. PLAIN External authentication using LDAP. You can also use PLAIN for authenticating in-database users. PLAIN transmits passwords in plain text. This mechanism is available only in MongoDB Enterprise. GSSAPI External authentication using Kerberos. This mechanism is available only in MongoDB Enterprise.
- --dbpath <path>¶
Specifies the directory of the MongoDB data files. The --dbpath option lets the mongoexport attach directly to the local data files without going through a running mongod. When run with --dbpath, the mongoexport locks access to the data files. No mongod can access the files while the mongoexport process runs.
- --directoryperdb¶
When used in conjunction with the corresponding option in mongod, allows mongoexport to export data from MongoDB instances that have every database’s files saved in discrete directories on the disk. This option is only relevant when specifying the --dbpath option.
- --journal¶
Enables the durability journal to ensure data files remain valid and recoverable. This option applies only when you specify the --dbpath option. The mongoexport enables journaling by default on 64-bit builds of versions after 2.0.
- --db <database>, -d¶
Specifies the name of the database on which to run the mongoexport.
- --collection <collection>, -c¶
Specifies the collection to export.
- --fields <field1[,field2]>, -f¶
Specifies a field or fields to include in the export. Use a comma separated list of fields to specify multiple fields.
For --csv output formats, mongoexport includes only the specified field(s), and the specified field(s) can be a field within a sub-document.
For JSON output formats, mongoexport includes only the specified field(s) and the _id field, and if the specified field(s) is a field within a sub-document, the mongoexport includes the sub-document with all its fields, not just the specified field within the document.
- --fieldFile <filename>¶
An alternative to --fields. The --fieldFile option allows you to specify in a file the field or fields to include in the export and is only valid with the --csv option. The file must have only one field per line, and the line(s) must end with the LF character (0x0A).
mongoexport includes only the specified field(s). The specified field(s) can be a field within a sub-document.
- --query <JSON>, -q¶
Provides a JSON document as a query that optionally limits the documents returned in the export. Specify JSON in strict format.
For example, given a collection named records in the database test with the following documents:
{ "_id" : ObjectId("51f0188846a64a1ed98fde7c"), "a" : 1 } { "_id" : ObjectId("520e61b0c6646578e3661b59"), "a" : 1, "b" : 2 } { "_id" : ObjectId("520e642bb7fa4ea22d6b1871"), "a" : 2, "b" : 3, "c" : 5 } { "_id" : ObjectId("520e6431b7fa4ea22d6b1872"), "a" : 3, "b" : 3, "c" : 6 } { "_id" : ObjectId("520e6445b7fa4ea22d6b1873"), "a" : 5, "b" : 6, "c" : 8 }
The following mongoexport uses the -q option to export only the documents with the field a greater than or equal to ($gte) to 3:
mongoexport -d test -c records -q "{ a: { \$gte: 3 } }" --out exportdir/myRecords.json
The resulting file contains the following documents:
{ "_id" : { "$oid" : "520e6431b7fa4ea22d6b1872" }, "a" : 3, "b" : 3, "c" : 6 } { "_id" : { "$oid" : "520e6445b7fa4ea22d6b1873" }, "a" : 5, "b" : 6, "c" : 8 }
You can sort the results with the --sort option to mongoexport.
- --csv¶
Changes the export format to a comma-separated-values (CSV) format. By default mongoexport writes data using one JSON document for every MongoDB document.
If you specify --csv, then you must also use either the --fields or the --fieldFile option to declare the fields to export from the collection.
- --out <file>, -o¶
Specifies a file to write the export to. If you do not specify a file name, the mongoexport writes data to standard output (e.g. stdout).
- --jsonArray¶
Modifies the output of mongoexport to write the entire contents of the export as a single JSON array. By default mongoexport writes data using one JSON document for every MongoDB document.
- --slaveOk, -k¶
Allows mongoexport to read data from secondary or slave nodes when using mongoexport with a replica set. This option is only available if connected to a mongod or mongos and is not available when used with the “mongoexport --dbpath” option.
This is the default behavior.
- --forceTableScan¶
2.2 新版功能.
Forces mongoexport to scan the data store directly: typically, mongoexport saves entries as they appear in the index of the _id field. Use --forceTableScan to skip the index and scan the data directly. Typically there are two cases where this behavior is preferable to the default:
- If you have key sizes over 800 bytes that would not be present in the _id index.
- Your database uses a custom _id field.
When you run with --forceTableScan, mongoexport does not use $snapshot. As a result, the export produced by mongoexport can reflect the state of the database at many different points in time.
警告
Use --forceTableScan with extreme caution and consideration.
- --skip <number>¶
Use --skip to control where mongoexport begins exporting documents. See skip() for information about the underlying operation.
- --limit <number>¶
Specifies a maximum number of documents to include in the export. See limit() for information about the underlying operation.
- --sort <JSON>¶
Specifies an ordering for exported results. If an index does not exist that can support the sort operation, the results must be less than 32 megabytes.
Use --sort conjunction with --skip and --limit to limit number of exported documents.
mongoexport -d test -c records --sort '{a: 1}' --limit 100 --out export.0.json mongoexport -d test -c records --sort '{a: 1}' --limit 100 --skip 100 --out export.1.json mongoexport -d test -c records --sort '{a: 1}' --limit 100 --skip 200 --out export.2.json
See sort() for information about the underlying operation.
Use¶
Export in CSV Format¶
In the following example, mongoexport exports the collection contacts from the users database from the mongod instance running on the localhost port number 27017. This command writes the export data in CSV format into a file located at /opt/backups/contacts.csv. The fields.txt file contains a line-separated list of fields to export.
mongoexport --db users --collection contacts --csv --fieldFile fields.txt --out /opt/backups/contacts.csv
Export in JSON Format¶
The next example creates an export of the collection contacts from the MongoDB instance running on the localhost port number 27017, with journaling explicitly enabled. This writes the export to the contacts.json file in JSON format.
mongoexport --db sales --collection contacts --out contacts.json --journal
Export Collection Directly From Data Files¶
The following example exports the collection contacts from the sales database located in the MongoDB data files located at /srv/mongodb/. This operation writes the export to standard output in JSON format.
mongoexport --db sales --collection contacts --dbpath /srv/mongodb/
警告
The above example will only succeed if there is no mongod connected to the data files located in the /srv/mongodb/ directory.
Export from Remote Host Running with Authentication¶
The following example exports the collection contacts from the database marketing . This data resides on the MongoDB instance located on the host mongodb1.example.net running on port 37017, which requires the username user and the password pass.
mongoexport --host mongodb1.example.net --port 37017 --username user --password pass --collection contacts --db marketing --out mdb1-examplenet.json
Type Fidelity¶
警告
mongoimport and mongoexport do not reliably preserve all rich BSON data types because JSON can only represent a subset of the types supported by BSON. As a result, data exported or imported with these tools may lose some measure of fidelity. See MongoDB Extended JSON for more information.
JSON can only represent a subset of the types supported by BSON. To preserve type information, mongoexport uses the strict mode representation for certain types.
For example, the following insert operation in the mongo shell uses the mongoShell mode representation for the BSON types data_date and data_numberlong:
use test
db.traffic.insert( { _id: 1, volume: NumberLong(2980000), date: new Date() } )
Use mongoexport to export the data:
mongoexport --db test --collection traffic --out traffic.json
The exported data is in strict mode representation to preserve type information:
{ "_id" : 1, "volume" : { "$numberLong" : "2980000" }, "date" : { "$date" : "2014-03-13T13:47:42.483-0400" } }
See MongoDB Extended JSON for a complete list of these types and the representations used.