mongodb语法实践

Days(11.14)

mongodb之前都是负责搭建、维护、备份、监控等操作。闲时来总结一下语法。

查询

根据条件查询数据量

登录数据库操作

1	> db.getCollection('Tables').find({"字段":"条件","字段":"条件"}).count();

查看数据库表

1	> show collections

查看mongodb的连接数

1	> db.serverStatus().connections

创建

创建用户、数据库

创建数据库
1
> use xxx

创建一个用户，拥有基本的读写权限

1	> db.createUser({user:"xxx",pwd:"xxx",roles:[{role:"readWrite",db:"xxx"}]})

创建用户需要赋予dbAdmin权限

dbAdmin: 允许用户在指定数据库中执行管理函数，如索引创建、删除，查看统计或访问system.profile

1	> db.createUser({user:"demo",pwd:"demo",roles:[{role:"readWrite",db:"kxlChannel"},{role:"dbAdmin",db:"kxlChannel"}]})

注: role 权限要是readWrite,不能赋予dbadmin，否则不能操作数据库

删除

删除账户和数据库

删除账户
1
> db.dropUser("xxx")

删除数据库

> db.dropDatabase("xxx")

# 还可以
> use names
> db.dropDatabase()

索引

创建索引

1 2	> db.表.ensureIndex({"字段":1},{"unique":true}) > db.表.ensureIndex({"字段":1},{"unique":true})

查看索引

1	> db.表.getIndexes()

查看表数据是否引用了索引

1	> db.表.find({"字段":"值"}).explain()

删除指定索引

1	> db.表.dropIndex("索引")

删除表全部索引

1	> db.表.dropIndexes()

备份

根据条件导出部分数据

$  mongoexport --db=数据库 --collection=表 --username=账户 --password=密码 --authenticationDatabase=认证的数据库  --query='{"条件","条件"}' --fields="导出的字段" --type=csv --out=/home/ll

参数介绍:
–db: 数据库
–collection: 表
–username: 账户
–password: 密码
–authenticationDatabase: 需要认证的数据库
–query: 条件
–fields: 导出的字段
–type: 导出的格式，默认是json，这里导出为csv，支持两种json和csv格式
–out: 导出路径文件

更多参数参考 –help

general options:
      --help                                      print usage
      --version                                   print the tool version and exit
verbosity options:
  -v, --verbose=<level>                           more detailed log output (include multiple times for more verbosity, e.g. -vvvvv, or specify a numeric value, e.g. --verbose=N)
      --quiet                                     hide all log output
connection options:
  -h, --host=<hostname>                           mongodb host to connect to (setname/host1,host2 for replica sets)
      --port=<port>                               server port (can also use --host hostname:port)
kerberos options:
      --gssapiServiceName=<service-name>          service name to use when authenticating using GSSAPI/Kerberos ('mongodb' by default)
      --gssapiHostName=<host-name>                hostname to use when authenticating using GSSAPI/Kerberos (remote server's address by default)
ssl options:
      --ssl                                       connect to a mongod or mongos that has ssl enabled
      --sslCAFile=<filename>                      the .pem file containing the root certificate chain from the certificate authority
      --sslPEMKeyFile=<filename>                  the .pem file containing the certificate and key
      --sslPEMKeyPassword=<password>              the password to decrypt the sslPEMKeyFile, if necessary
      --sslCRLFile=<filename>                     the .pem file containing the certificate revocation list
      --sslAllowInvalidCertificates               bypass the validation for server certificates
      --sslAllowInvalidHostnames                  bypass the validation for server name
      --sslFIPSMode                               use FIPS mode of the installed openssl library
authentication options:
  -u, --username=<username>                       username for authentication
  -p, --password=<password>                       password for authentication
      --authenticationDatabase=<database-name>    database that holds the user's credentials
      --authenticationMechanism=<mechanism>       authentication mechanism to use
namespace options:
  -d, --db=<database-name>                        database to use
  -c, --collection=<collection-name>              collection to use
uri options:
      --uri=mongodb-uri                           mongodb uri connection string
output options:
  -f, --fields=<field>[,<field>]*                 comma separated list of field names (required for exporting CSV) e.g. -f "name,age"
      --fieldFile=<filename>                      file with field names - 1 per line
      --type=<type>                               the output format, either json or csv (defaults to 'json') (default: json)
  -o, --out=<filename>                            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
      --noHeaderLine                              export CSV data without a list of field names at the first line
querying options:
  -q, --query=<json>                              query filter, as a JSON string, e.g., '{x:{$gt:1}}'
      --queryFile=<filename>                      path to a file containing a query filter (JSON)
  -k, --slaveOk                                   allow secondary reads if available (default true) (default: false)
      --readPreference=<string>|<json>            specify either a preference name or a preference json object
      --forceTableScan                            force a table scan (do not use $snapshot)
      --skip=<count>                              number of documents to skip
      --limit=<count>                             limit the number of documents to export
      --sort=<json>                               sort order, as a JSON string, e.g. '{x:1}'
      --assertExists                              if specified, export fails if the collection does not exist (default: false)