rocksdb/tools/rdb/API.md

JavaScript API

DBWrapper

Constructor

# Creates a new database wrapper object
RDB()

Open

# Open a new or existing RocksDB database.
#
# db_name         (string)   - Location of the database (inside the
#                              `/tmp` directory).
# column_families (string[]) - Names of additional column families
#                              beyond the default. If there are no other
#                              column families, this argument can be
#                              left off.
#
# Returns true if the database was opened successfully, or false otherwise
db_obj.(db_name, column_families = [])

Get

# Get the value of a given key.
#
# key           (string) - Which key to get the value of.
# column_family (string) - Which column family to check for the key.
#                          This argument can be left off for the default
#                          column family
#
# Returns the value (string) that is associated with the given key if
# one exists, or null otherwise.
db_obj.get(key, column_family = { default })

Put

# Associate a value with a key.
#
# key           (string) - Which key to associate the value with.
# value         (string) - The value to associate with the key.
# column_family (string) - Which column family to put the key-value pair
#                          in. This argument can be left off for the
#                          default column family.
#
# Returns true if the key-value pair was successfully stored in the
# database, or false otherwise.
db_obj.put(key, value, column_family = { default })

Delete

# Delete a value associated with a given key.
#
# key           (string) - Which key to delete the value of..
# column_family (string) - Which column family to check for the key.
#                          This argument can be left off for the default
#                          column family
#
# Returns true if an error occured while trying to delete the key in
# the database, or false otherwise. Note that this is NOT the same as
# whether a value was deleted; in the case of a specified key not having
# a value, this will still return true. Use the `get` method prior to
# this method to check if a value existed before the call to `delete`.
db_obj.delete(key, column_family = { default })

Dump

# Print out all the key-value pairs in a given column family of the
# database.
#
# column_family (string) - Which column family to dump the pairs from.
#                          This argument can be left off for the default
#                          column family.
#
# Returns true if the keys were successfully read from the database, or
# false otherwise.
db_obj.dump(column_family = { default })

WriteBatch

# Execute an atomic batch of writes (i.e. puts and deletes) to the
# database.
#
# cf_batches (BatchObject[]; see below) - Put and Delete writes grouped
#                                         by column family to execute
#                                         atomically.
#
# Returns true if the argument array was well-formed and was
# successfully written to the database, or false otherwise.
db_obj.writeBatch(cf_batches)

CreateColumnFamily

# Create a new column familiy for the database.
#
# column_family_name (string) - Name of the new column family.
#
# Returns true if the new column family was successfully created, or
# false otherwise.
db_obj.createColumnFamily(column_family_name)

CompactRange

# Compact the underlying storage for a given range.
#
# In addition to the endpoints of the range, the method is overloaded to
# accept a non-default column family, a set of options, or both.
#
# begin (string)         - First key in the range to compact.
# end   (string)         - Last key in the range to compact.
# options (object)       - Contains a subset of the following key-value
#                          pairs:
#                            * 'target_level'   => int
#                            * 'target_path_id' => int
# column_family (string) - Which column family to compact the range in.
db_obj.compactRange(begin, end)
db_obj.compactRange(begin, end, options)
db_obj.compactRange(begin, end, column_family)
db_obj.compactRange(begin, end, options, column_family)

Close

# Close an a database and free the memory associated with it.
#
# Return null.
# db_obj.close()

BatchObject

Structure

A BatchObject must have at least one of the following key-value pairs:

• 'put' => Array of ['string1', 'string1'] pairs, each of which signifies that the key 'string1' should be associated with the value 'string2'
• 'delete' => Array of strings, each of which is a key whose value should be deleted.

The following key-value pair is optional:

• 'column_family' => The name (string) of the column family to apply the changes to.

Examples

# Writes the key-value pairs 'firstname' => 'Saghm' and
# 'lastname' => 'Rossi' atomically to the database.
db_obj.writeBatch([
    {
        put: [ ['firstname', 'Saghm'], ['lastname', 'Rossi'] ]
    }
]);


# Deletes the values associated with 'firstname' and 'lastname' in
# the default column family and adds the key 'number_of_people' with
# with the value '2'. Additionally, adds the key-value pair
# 'name' => 'Saghm Rossi' to the column family 'user1' and the pair
# 'name' => 'Matt Blaze' to the column family 'user2'. All writes
# are done atomically.
db_obj.writeBatch([
    {
        put: [ ['number_of_people', '2'] ],
        delete: ['firstname', 'lastname']
    },
    {
        put: [ ['name', 'Saghm Rossi'] ],
        column_family: 'user1'
    },
    {
        put: [ ['name', Matt Blaze'] ],
        column_family: 'user2'
    }
]);