MapR Database Shell (JSON Tables)

The mapr dbshell is a tool that enables you to create and perform basic manipulation of JSON tables and documents. You run dbshell by typing mapr dbshell on the command line after logging into a node in a MapR Data Platform cluster.

NOTE MapR Database Shell does not support MapR Event Store For Apache Kafka streams operations.

Permissions

Before running dbshell, your user ID must have both the readAce and writeAce permissions on the volume. For information about these permissions, see Managing Whole Volume ACEs.

SUSE Linux Error Messages

When you run dbshell on SUSE Linux, you might see the following messages:
[INFO] Unable to bind key for unsupported operation: backward-delete-word
[INFO] Unable to bind key for unsupported operation: up-history
[INFO] Unable to bind key for unsupported operation: down-history
To suppress these messages, edit the /etc/inputrc file and rename the keywords as follows:
Original name New name
backward-delete-word backward-kill-word
down-history next-history
up-history previous-history

Command Descriptions

To get a list of supported dbshell commands, run help at the shell prompt:

* ! - Allows execution of operating system (OS) commands
* // - Inline comment markers (start of line only)
* ; - Inline comment markers (start of line only)
* cat - Print the content of the specified file on the standard output
* cd - Change the current directory to the specified path.
* clear - Clears the console
* cls - Clears the console
* create - Create a json table at the given path.
* date - Displays the local date and time
* debug - Sets/shows the debug mode.
* delete - Delete a document from the table.
* desc - Describes the properties of a table.
* drop - Deletes a MapR-DB json table.
* exists - Returns true if the table exists.
* exit - Exits the shell
* find - Retrieves one or more documents from the table.
* findbyid - Retrieves a single document from the table.
* help - List all commands usage
* indexlist - Retrieves the list of indexes for the specified table.
* indexscan - Scan the index and return the document in their natural order.
* insert - Inserts or replaces a document into the table.
* jsonoptions - Sets/shows the Json output options.
* list - Lists all tables in a folder or matching the specified pattern.
* ls - Lists files and folders.
* mkdir - Create a directory at the specified path.
* pwd - Print the absolute path of the current working directory.
* quit - Exits the shell
* replace - Replace a document based on condition.
* script - Parses the specified resource file and executes its commands
* system properties - Shows the shell's properties
* tableoptions - Sets/shows the MapR-DB Table access options.
* update - Update field in a single document.
* version - Displays shell version
* whoami - Prints the current MapR-DB Shell user.

Parameters

Various components of these commands will be either be in JSON (in case a list of key-value is required) or a single value following a switch identifying the component.

To get a list of parameters for a specific command, run help <command> at the prompt. For example: help find returns the following: 
maprdb root:> help find
Command:                   find
Description:               Retrieves one or more documents from the table.
Options:                   
  *, --t, --table          Table path. [required]
  --id                     Document Id.
  --fromid                 Document Id to start from (inclusive)
  --toid                   Document Id to stop at (exclusive)
  --limit                  Maximum number of documents to return.
  --withtags, --withTags   Enables/disables printing with extended Type Tags.
  --pretty                 Enables/disables pretty printing of the document.
  --offset                 Skip first n number of rows in the result.
  --orderby                Sort result by the given fields.
  --c, --where             Condition in JSON format
  --f, --fields            Projections in JSON documents
  --q, --query             Query in JSON documents
Examples:
  find /tables/users
  find /tables/users --fromid user001 --toid user00a --limit 32

Value Types

Extended type values are shown using type tags. The scalar types are represented as follows:

  • {"$binary":"AAAASw=="} for binary values
  • {"$numberLong":21491} for whole numbers like long, short, byte, short
  • {"$numeric":47.92} for numeric types like float and double
  • {"$time":"14:35:28.981"} for time type values
  • {"$date":"2017-04-24T22:35:28.981Z"} for timestamp values
  • {"$dateDay":"2017-04-23"} for date type values

Bulk Operations

Currently, bulk conditional operations are not supported.