Class: Mongo::DB

Inherits:
Object show all
Defined in:
lib/mongo/db.rb

Overview

A MongoDB database.

Constant Summary

SYSTEM_NAMESPACE_COLLECTION = 
"system.namespaces"
SYSTEM_INDEX_COLLECTION = 
"system.indexes"
SYSTEM_PROFILE_COLLECTION = 
"system.profile"
SYSTEM_USER_COLLECTION = 
"system.users"
SYSTEM_JS_COLLECTION = 
"system.js"
SYSTEM_COMMAND_COLLECTION = 
"$cmd"
@@current_request_id =

Counter for generating unique request ids.

0

Instance Attribute Summary (collapse)

Instance Method Summary (collapse)

Constructor Details

- (DB) initialize(name, connection, opts = {})

Instances of DB are normally obtained by calling Mongo#db.

Parameters:

  • name (String) —

    the database name.

  • connection (Mongo::Connection) —

    a connection object pointing to MongoDB. Note that databases are usually instantiated via the Connection class. See the examples below.

  • opts (Hash) (defaults to: {}) —

    a customizable set of options

Options Hash (opts):

  • :strict (Boolean) — default: False —

    If true, collections must exist to be accessed and must not exist to be created. See DB#collection and DB#create_collection.

  • :pk (Object, #create_pk(doc)) — default: BSON::ObjectId —

    A primary key factory object, which should take a hash and return a hash which merges the original hash with any primary key fields the factory wishes to inject. (NOTE: if the object already has a primary key, the factory should not inject a new key).

  • :safe (Boolean, Hash) — default: false —

    Set the default safe-mode options propagated to Collection objects instantiated off of this DB. If no value is provided, the default value set on this instance’s Connection object will be used. This default can be overridden upon instantiation of any collection by explicity setting a :safe value on initialization

  • :cache_time (Integer) — default: 300 —

    Set the time that all ensure_index calls should cache the command.

Core docs:



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# File 'lib/mongo/db.rb', line 78

def initialize(name, connection, opts={})
  @name       = Mongo::Support.validate_db_name(name)
  @connection = connection
  @strict     = opts[:strict]
  @pk_factory = opts[:pk]
  @safe       = opts.fetch(:safe, @connection.safe)
  if value = opts[:read]
    Mongo::Support.validate_read_preference(value)
  else
    value = @connection.read_preference
  end
  @read_preference = value.is_a?(Hash) ? value.dup : value
  @cache_time = opts[:cache_time] || 300 #5 minutes.
end

Instance Attribute Details

- (Object) cache_time

The length of time that Collection.ensure_index should cache index calls



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# File 'lib/mongo/db.rb', line 54

def cache_time
  @cache_time
end

- (Object) connection (readonly)

The Mongo::Connection instance connecting to the MongoDB server.



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# File 'lib/mongo/db.rb', line 51

def connection
  @connection
end

- (Object) name (readonly)

The name of the database and the local safe option.



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# File 'lib/mongo/db.rb', line 48

def name
  @name
end

- (Object) safe (readonly)

The name of the database and the local safe option.



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# File 'lib/mongo/db.rb', line 48

def safe
  @safe
end

- (Object) strict=(value) (writeonly)

Strict mode enforces collection existence checks. When true, asking for a collection that does not exist, or trying to create a collection that already exists, raises an error.

Strict mode is disabled by default, but enabled (true) at any time.



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# File 'lib/mongo/db.rb', line 42

def strict=(value)
  @strict = value
end

Instance Method Details

- (String) add_stored_function(function_name, code)

Adds a stored Javascript function to the database which can executed server-side in map_reduce, db.eval and $where clauses.

Parameters:

Returns:

  • (String) —

    the function name saved to the database



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# File 'lib/mongo/db.rb', line 150

def add_stored_function(function_name, code)
  self[SYSTEM_JS_COLLECTION].save(
    {
      "_id" => function_name, 
      :value => BSON::Code.new(code)
    }
  )
end

- (Hash) add_user(username, password, read_only = false)

Adds a user to this database for use with authentication. If the user already exists in the system, the password will be updated.

Parameters:

  • username (String)
  • password (String)
  • read_only (Boolean) (defaults to: false) —

    Create a read-only user.

Returns:

  • (Hash) —

    an object representing the user.



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# File 'lib/mongo/db.rb', line 182

def add_user(username, password, read_only = false)
  users = self[SYSTEM_USER_COLLECTION]
  user  = users.find_one({:user => username}) || {:user => username}
  user['pwd'] = Mongo::Support.hash_password(username, password)
  user['readOnly'] = true if read_only;
  users.save(user)
  return user
end

- (Boolean) authenticate(username, password, save_auth = true)

Authenticate with the given username and password. Note that mongod must be started with the --auth option for authentication to be enabled.

Parameters:

  • username (String)
  • password (String)
  • save_auth (Boolean) (defaults to: true) —

    Save this authentication to the connection object using Connection#add_auth. This will ensure that the authentication will be applied on database reconnect. Note that this value must be true when using connection pooling.

Returns:

  • (Boolean)

Raises:

Core docs:



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# File 'lib/mongo/db.rb', line 108

def authenticate(username, password, save_auth=true)
  if @connection.pool_size > 1
    if !save_auth
      raise MongoArgumentError, "If using connection pooling, :save_auth must be set to true."
    end
  end

  @connection.best_available_socket do |socket|
    issue_authentication(username, password, save_auth, :socket => socket)
  end

  @connection.authenticate_pools
end

- (Mongo::Collection) collection(name, opts = {}) Also known as: []

Get a collection by name.

Parameters:

  • name (String, Symbol) —

    the collection name.

  • opts (Hash) (defaults to: {}) —

    any valid options that can be passed to Collection#new.

Returns:

Raises:

  • (MongoDBError) —

    if collection does not already exist and we’re in strict mode.



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# File 'lib/mongo/db.rb', line 311

def collection(name, opts={})
  if strict? && !collection_names.include?(name.to_s)
    raise Mongo::MongoDBError, "Collection #{name} doesn't exist. " +
      "Currently in strict mode."
  else
    opts = opts.dup
    opts[:safe] = opts.fetch(:safe, @safe)
    opts.merge!(:pk => @pk_factory) unless opts[:pk]
    Collection.new(name, self, opts)
  end
end

- (Array) collection_names

Get an array of collection names in this database.

Returns:

  • (Array) 


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# File 'lib/mongo/db.rb', line 233

def collection_names
  names = collections_info.collect { |doc| doc['name'] || '' }
  names = names.delete_if {|name| name.index(@name).nil? || name.index('$')}
  names.map {|name| name.sub(@name + '.', '')}
end

- (Array<Mongo::Collection>) collections

Get an array of Collection instances, one for each collection in this database.

Returns:



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# File 'lib/mongo/db.rb', line 242

def collections
  collection_names.map do |name|
    Collection.new(name, self)
  end
end

- (Mongo::Cursor) collections_info(coll_name = nil)

Get info on system namespaces (collections). This method returns a cursor which can be iterated over. For each collection, a hash will be yielded containing a 'name' string and, optionally, an 'options' hash.

Parameters:

  • coll_name (String) (defaults to: nil) —

    return info for the specifed collection only.

Returns:



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# File 'lib/mongo/db.rb', line 255

def collections_info(coll_name=nil)
  selector = {}
  selector[:name] = full_collection_name(coll_name) if coll_name
  Cursor.new(Collection.new(SYSTEM_NAMESPACE_COLLECTION, self), :selector => selector)
end

- (Hash) command(selector, opts = {})

Send a command to the database.

Note: DB commands must start with the "command" key. For this reason, any selector containing more than one key must be an OrderedHash.

Note also that a command in MongoDB is just a kind of query that occurs on the system command collection ($cmd). Examine this method's implementation to see how it works.

key, specifying the command to be performed. In Ruby 1.9, OrderedHash isn't necessary since hashes are ordered by default.

command fails.

Parameters:

  • selector (OrderedHash, Hash) —

    an OrderedHash, or a standard Hash with just one

  • opts (Hash) (defaults to: {}) —

    a customizable set of options

Options Hash (opts):

  • :check_response (Boolean) — default: true —

    If true, raises an exception if the

  • :socket (Socket) —

    a socket to use for sending the command. This is mainly for internal use.

Returns:

Raises:

Core docs:



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# File 'lib/mongo/db.rb', line 502

def command(selector, opts={})
  check_response = opts.fetch(:check_response, true)
  socket         = opts[:socket]
  raise MongoArgumentError, "command must be given a selector" unless selector.is_a?(Hash) && !selector.empty?
  if selector.keys.length > 1 && RUBY_VERSION < '1.9' && selector.class != BSON::OrderedHash
    raise MongoArgumentError, "DB#command requires an OrderedHash when hash contains multiple keys"
  end

  begin
    result = Cursor.new(system_command_collection,
      :limit => -1, :selector => selector, :socket => socket).next_document
  rescue OperationFailure => ex
    raise OperationFailure, "Database command '#{selector.keys.first}' failed: #{ex.message}"
  end

  if result.nil?
    raise OperationFailure, "Database command '#{selector.keys.first}' failed: returned null."
  elsif (check_response && !ok?(result))
    message = "Database command '#{selector.keys.first}' failed: ("
    message << result.map do |key, value|
      "#{key}: '#{value}'"
    end.join('; ')
    message << ').'
    code = result['code'] || result['assertionCode']
    raise OperationFailure.new(message, code, result)
  else
    result
  end
end

- (Mongo::Collection) create_collection(name, opts = {})

Create a collection.

new collection. If strict is true, will raise an error if collection name already exists.

Parameters:

  • name (String, Symbol) —

    the name of the new collection.

  • opts (Hash) (defaults to: {}) —

    a customizable set of options

Options Hash (opts):

  • :capped (Boolean) — default: False —

    created a capped collection.

  • :size (Integer) — default: Nil —

    If capped is true, specifies the maximum number of bytes for the capped collection. If false, specifies the number of bytes allocated for the initial extent of the collection.

  • :max (Integer) — default: Nil —

    If capped is true, indicates the maximum number of records in a capped collection.

Returns:

Raises:

  • (MongoDBError) —

    raised under two conditions: either we’re in strict mode and the collection already exists or collection creation fails on the server.



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# File 'lib/mongo/db.rb', line 283

def create_collection(name, opts={})
  name = name.to_s
  if collection_names.include?(name)
    if strict?
      raise MongoDBError, "Collection #{name} already exists. " +
        "Currently in strict mode."
    else
      return Collection.new(name, self, opts)
    end
  end

  # Create a new collection.
  oh = BSON::OrderedHash.new
  oh[:create] = name
  doc = command(oh.merge(opts || {}))
  return Collection.new(name, self, :pk => @pk_factory) if ok?(doc)
  raise MongoDBError, "Error creating collection: #{doc.inspect}"
end

- (Hash) dereference(dbref)

Dereference a DBRef, returning the document it points to.

Parameters:

  • dbref (Mongo::DBRef)

Returns:

  • (Hash) —

    the document indicated by the db reference.

See Also:



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# File 'lib/mongo/db.rb', line 394

def dereference(dbref)
  collection(dbref.namespace).find_one("_id" => dbref.object_id)
end

- (Boolean) drop_collection(name)

Drop a collection by name.

Parameters:

Returns:

  • (Boolean) —

    true on success or false if the collection name doesn't exist.



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# File 'lib/mongo/db.rb', line 329

def drop_collection(name)
  return true unless collection_names.include?(name.to_s)

  ok?(command(:drop => name))
end

- (True) drop_index(collection_name, index_name)

Drop an index from a given collection. Normally called from Collection#drop_index or Collection#drop_indexes.

Parameters:

Returns:

  • (True) —

    returns true on success.

Raises:

  • MongoDBError if there’s an error renaming the collection.



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# File 'lib/mongo/db.rb', line 442

def drop_index(collection_name, index_name)
  oh = BSON::OrderedHash.new
  oh[:deleteIndexes] = collection_name
  oh[:index] = index_name.to_s
  doc = command(oh, :check_response => false)
  ok?(doc) || raise(MongoDBError, "Error with drop_index command: #{doc.inspect}")
end

- (Boolean) error?

Return true if an error was caused by the most recently executed database operation.

Returns:

  • (Boolean) 


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# File 'lib/mongo/db.rb', line 358

def error?
  get_last_error['err'] != nil
end

- (String) eval(code, *args)

Evaluate a JavaScript expression in MongoDB.

Parameters:

  • code (String, Code) —

    a JavaScript expression to evaluate server-side.

  • args (Integer, Hash) —

    any additional argument to be passed to the code expression when it’s run on the server.

Returns:

  • (String) —

    the return value of the function.



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# File 'lib/mongo/db.rb', line 405

def eval(code, *args)
  if not code.is_a? BSON::Code
    code = BSON::Code.new(code)
  end

  oh = BSON::OrderedHash.new
  oh[:$eval] = code
  oh[:args]  = args
  doc = command(oh)
  doc['retval']
end

- (String) full_collection_name(collection_name)

A shortcut returning db plus dot plus collection name.

Parameters:

Returns:



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# File 'lib/mongo/db.rb', line 537

def full_collection_name(collection_name)
  "#{@name}.#{collection_name}"
end

- (Hash) get_last_error(opts = {})

Run the getlasterror command with the specified replication options.

Parameters:

  • opts (Hash) (defaults to: {}) —

    a customizable set of options

Options Hash (opts):

  • :fsync (Boolean) — default: false —
  • :w (Integer) — default: nil —
  • :wtimeout (Integer) — default: nil —
  • :j (Boolean) — default: false —

Returns:

  • (Hash) —

    the entire response to getlasterror.

Raises:



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# File 'lib/mongo/db.rb', line 345

def get_last_error(opts={})
  cmd = BSON::OrderedHash.new
  cmd[:getlasterror] = 1
  cmd.merge!(opts)
  doc = command(cmd, :check_response => false)
  raise MongoDBError, "error retrieving last error: #{doc.inspect}" unless ok?(doc)
  doc
end

- (Hash) index_information(collection_name)

Get information on the indexes for the given collection. Normally called by Collection#index_information.

Parameters:

Returns:

  • (Hash) —

    keys are index names and the values are lists of [key, direction] pairs defining the index.



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# File 'lib/mongo/db.rb', line 457

def index_information(collection_name)
  sel  = {:ns => full_collection_name(collection_name)}
  info = {}
  Cursor.new(Collection.new(SYSTEM_INDEX_COLLECTION, self), :selector => sel).each do |index|
    info[index['name']] = index
  end
  info
end

- (Object) issue_authentication(username, password, save_auth = true, opts = {})

Raises:



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# File 'lib/mongo/db.rb', line 122

def issue_authentication(username, password, save_auth=true, opts={})
  doc = command({:getnonce => 1}, :check_response => false, :socket => opts[:socket])
  raise MongoDBError, "Error retrieving nonce: #{doc}" unless ok?(doc)
  nonce = doc['nonce']

  auth = BSON::OrderedHash.new
  auth['authenticate'] = 1
  auth['user'] = username
  auth['nonce'] = nonce
  auth['key'] = Mongo::Support.auth_key(username, password, nonce)
  if ok?(doc = self.command(auth, :check_response => false, :socket => opts[:socket]))
    if save_auth
      @connection.add_auth(@name, username, password)
    end
    true
  else
    message = "Failed to authenticate user '#{username}' on db '#{self.name}'"
    raise Mongo::AuthenticationError.new(message, doc['code'], doc)
  end
end

- (Object) issue_logout(opts = {}) 



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# File 'lib/mongo/db.rb', line 220

def issue_logout(opts={})
  doc = command({:logout => 1}, :socket => opts[:socket])
  if ok?(doc)
    @connection.remove_auth(@name)
    true
  else
    raise MongoDBError, "error logging out: #{doc.inspect}"
  end
end

- (Boolean) logout(opts = {})

Deauthorizes use for this database for this connection. Also removes any saved authentication in the connection class associated with this database.

Returns:

  • (Boolean)

Raises:



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# File 'lib/mongo/db.rb', line 212

def logout(opts={})
  if @connection.pool_size > 1
    @connection.logout_pools(@name)
  end

  issue_logout(opts)
end

- (Boolean) ok?(doc)

Return true if the supplied doc contains an 'ok' field with the value 1.

Parameters:

Returns:

  • (Boolean) 


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# File 'lib/mongo/db.rb', line 478

def ok?(doc)
  Mongo::Support.ok?(doc)
end

- (Object, Nil) pk_factory

The primary key factory object (or nil).

Returns:



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# File 'lib/mongo/db.rb', line 544

def pk_factory
  @pk_factory
end

- (Object) pk_factory=(pk_factory)

Specify a primary key factory if not already set.

Raises:



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# File 'lib/mongo/db.rb', line 551

def pk_factory=(pk_factory)
  if @pk_factory
    raise MongoArgumentError, "Cannot change primary key factory once it's been set"
  end

  @pk_factory = pk_factory
end

- (String, Nil) previous_error

Get the most recent error to have occured on this database.

This command only returns errors that have occured since the last call to DB#reset_error_history - returns nil if there is no such error.

Returns:

  • (String, Nil) —

    the text of the error or nil if no error has occurred.



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# File 'lib/mongo/db.rb', line 368

def previous_error
  error = command(:getpreverror => 1)
  if error["err"]
    error
  else
    nil
  end
end

- (Array) profiling_info

Get the current profiling information.

Returns:

  • (Array) —

    a list of documents containing profiling information.



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# File 'lib/mongo/db.rb', line 605

def profiling_info
  Cursor.new(Collection.new(SYSTEM_PROFILE_COLLECTION, self), :selector => {}).to_a
end

- (Symbol) profiling_level

Return the current database profiling level. If profiling is enabled, you can get the results using DB#profiling_info.

Returns:

  • (Symbol) —

    :off, :slow_only, or :all

Core docs:



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# File 'lib/mongo/db.rb', line 565

def profiling_level
  oh = BSON::OrderedHash.new
  oh[:profile] = -1
  doc = command(oh, :check_response => false)
  raise "Error with profile command: #{doc.inspect}" unless ok?(doc) && doc['was'].kind_of?(Numeric)
  case doc['was'].to_i
  when 0
    :off
  when 1
    :slow_only
  when 2
    :all
  else
    raise "Error: illegal profiling level value #{doc['was']}"
  end
end

- (Object) profiling_level=(level)

Set this database's profiling level. If profiling is enabled, you can get the results using DB#profiling_info.

Parameters:

  • level (Symbol) —

    acceptable options are :off, :slow_only, or :all.



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# File 'lib/mongo/db.rb', line 586

def profiling_level=(level)
  oh = BSON::OrderedHash.new
  oh[:profile] = case level
                 when :off
                   0
                 when :slow_only
                   1
                 when :all
                   2
                 else
                   raise "Error: illegal profiling level value #{level}"
                 end
  doc = command(oh, :check_response => false)
  ok?(doc) || raise(MongoDBError, "Error with profile command: #{doc.inspect}")
end

- (Object) read_preference

The value of the read preference. This will be either :primary, :secondary, or an object representing the tags to be read from.



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# File 'lib/mongo/db.rb', line 634

def read_preference
  @read_preference
end

- (Boolean) remove_stored_function(function_name)

Removes stored Javascript function from the database. Returns false if the function does not exist

Parameters:

Returns:

  • (Boolean) 


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# File 'lib/mongo/db.rb', line 165

def remove_stored_function(function_name)
  if self[SYSTEM_JS_COLLECTION].find_one({"_id" => function_name})
    self[SYSTEM_JS_COLLECTION].remove({"_id" => function_name}, :safe => true)
  else
    return false
  end
end

- (Boolean) remove_user(username)

Remove the given user from this database. Returns false if the user doesn't exist in the system.

Parameters:

Returns:

  • (Boolean) 


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# File 'lib/mongo/db.rb', line 197

def remove_user(username)
  if self[SYSTEM_USER_COLLECTION].find_one({:user => username})
    self[SYSTEM_USER_COLLECTION].remove({:user => username}, :safe => true)
  else
    return false
  end
end

- (True) rename_collection(from, to)

Rename a collection.

Parameters:

  • from (String) —

    original collection name.

  • to (String) —

    new collection name.

Returns:

  • (True) —

    returns true on success.

Raises:

  • MongoDBError if there’s an error renaming the collection.



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# File 'lib/mongo/db.rb', line 425

def rename_collection(from, to)
  oh = BSON::OrderedHash.new
  oh[:renameCollection] = "#{@name}.#{from}"
  oh[:to] = "#{@name}.#{to}"
  doc = DB.new('admin', @connection).command(oh, :check_response => false)
  ok?(doc) || raise(MongoDBError, "Error renaming collection: #{doc.inspect}")
end

- (Hash) reset_error_history

Reset the error history of this database

Calls to DB#previous_error will only return errors that have occurred since the most recent call to this method.

Returns:



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# File 'lib/mongo/db.rb', line 383

def reset_error_history
  command(:reseterror => 1)
end

- (Hash) stats

Return stats on this database. Uses MongoDB's dbstats command.

Returns:



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# File 'lib/mongo/db.rb', line 469

def stats
  self.command({:dbstats => 1})
end

- (Boolean) strict?

Returns the value of the strict flag.

Returns:

  • (Boolean) 


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# File 'lib/mongo/db.rb', line 45

def strict?; @strict; end

- (Hash) validate_collection(name)

Validate a named collection.

Parameters:

  • name (String) —

    the collection name.

Returns:

  • (Hash) —

    validation information.

Raises:

  • (MongoDBError) —

    if the command fails or there’s a problem with the validation data, or if the collection is invalid.



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# File 'lib/mongo/db.rb', line 617

def validate_collection(name)
  cmd = BSON::OrderedHash.new
  cmd[:validate] = name
  cmd[:full] = true
  doc = command(cmd, :check_response => false)
  if !ok?(doc)
    raise MongoDBError, "Error with validate command: #{doc.inspect}"
  end
  if (doc.has_key?('valid') && !doc['valid']) || (doc['result'] =~ /\b(exception|corrupt)\b/i)
    raise MongoDBError, "Error: invalid collection #{name}: #{doc.inspect}"
  end
  doc
end