diff --git a/source/reference/glossary.txt b/source/reference/glossary.txt index 7f73978aa07..7570eba220c 100644 --- a/source/reference/glossary.txt +++ b/source/reference/glossary.txt @@ -41,11 +41,11 @@ Glossary document A record in a MongoDB collection, and the basic unit of data - in MongoDB. Documents are analogous to JSON object, but exist in - the Database in a more type-rich format known as :term:`BSON`. + in MongoDB. Documents are analogous to JSON objects, but exist in + the database in a more type-rich format known as :term:`BSON`. field - A name-value pair in a term:`document`. Documents have zero + A name-value pair in a :term:`document `. Documents have zero or more fields. Fields are analogous to columns in relational databases. @@ -58,17 +58,11 @@ Glossary collection A namespace within a database for containing :term:`documents `. Collections do not enforce a schema, but they are otherwise - mostly analogous to RDBMS tables. - - map-reduce - A paradigm from functional programming used to implement aggregation - in a number of popular database servers. MongoDB uses map-reduce - in a command called :dbcommand:`mapReduce` to provide basic - map-reduce style aggregation. + mostly analogous to :term:`RDBMS` tables. $cmd A virtual :term:`collection` that exposes :term:`MongoDB`'s - term:`database commands `. + :term:`database commands `. JSON JavaScript Object Notation. A human-readable, plain text format @@ -95,14 +89,13 @@ Glossary replication and automated failover. MongoDB's recommended replication strategy. - .. seealso:: :term:`replication`, ":doc:`/replication`" and - ":doc:`/core/replication`." + .. seealso:: ":doc:`/replication`" and ":doc:`/core/replication`." replication A feature allowing multiple database servers to share the same data, thereby ensuring redundancy and facilitating load balancing. MongoDB supports two flavors of replication: master-slave replication - and replica sets + and replica sets. .. seealso:: :term:`replica set`, :term:`sharding`, ":doc:`/replication`." and ":doc:`/core/replication`." @@ -142,7 +135,7 @@ Glossary cluster`. mongod - The program implemeting the MongoDB database server. This server + The program implementing the MongoDB database server. This server typically runs as a :term:`daemon`. .. seealso:: ":doc:`/reference/mongod`." @@ -150,8 +143,7 @@ Glossary mongos The routing and load balancing process that acts an interface between an application and - a MongoDB :term:`shard cluster`. See - ":doc:`/reference/mongos`" for more information. + a MongoDB :term:`shard cluster`. .. seealso:: ":doc:`/reference/mongos`." @@ -194,8 +186,8 @@ Glossary capped collection A fixed-sized :term:`collection `. Once they reach their fixed size, capped collections automatically overwrite - their oldest entries. MongoDB's replication mechanism depends on - capped collections, but developers may also use them in their + their oldest entries. MongoDB's :term:`oplog` replication mechanism depends on + capped collections. Developers may also use capped collections in their applications. .. seealso:: The ":wiki:`Capped Collections `" wiki page. @@ -324,19 +316,19 @@ Glossary inserts a new document having the fields implied by the query selector and the update operation. - csv + CSV A text-based data format consisting of comma-separated values. This format is commonly used to exchange database between relational - database, since the format is well-suited to tabular data. You can + databases, since the format is well-suited to tabular data. You can import CSV files using :program:`mongoimport`. - tsv + TSV A text-based data format consisting of tab-separated values. This format is commonly used to exchange database between relational - database, since the format is well-suited to tabular data. You can - import CSV files using :program:`mongoimport`. + databases, since the format is well-suited to tabular data. You can + import TSV files using :program:`mongoimport`. - mime + MIME "Multipurpose Internet Mail Extensions." A standard set of type and encoding definitions used to declare the encoding and type of data in multiple data storage, transmission, and email @@ -360,7 +352,7 @@ Glossary held allows concurrent readers, but no writers. config database - One or three :program:`mongod` instances that store all the + One of three :program:`mongod` instances that store all the metadata associated with a :term:`shard cluster`. balancer @@ -370,7 +362,7 @@ Glossary the balancer for all maintenance operations on a shard cluster. fsync - An system call that flushes all dirty, in-memory pages to disk. MongoDB + A system call that flushes all dirty, in-memory pages to disk. MongoDB calls ``fsync()`` every 60 seconds. chunk @@ -424,9 +416,9 @@ Glossary The conventional name for a background, non-interactive process. - pid - A process ID. On Unix-like systems, a unique integer assigned to - each running process. You can use a process's PID to inspect + PID + A process identifier. On UNIX-like systems, a unique integer PID is assigned to + each running process. You can use a PID to inspect a running process and send signals to it. JSONP @@ -435,7 +427,7 @@ Glossary REST An API design pattern centered around the idea of - resources and the CRUD operations that apply to them. Typically + resources and the :term:`CRUD` operations that apply to them. Typically implemented over HTTP. MongoDB provides a simple HTTP REST interface that allows HTTP clients to run commands against the server. @@ -458,12 +450,12 @@ Glossary ":doc:`/core/replication`." _id - A field containing a unique ID, typically a BSON Object ID. - If not specified, this value is automatically assigned while + A field containing a unique ID, typically a BSON :term:`ObjectId`. + If not specified, this value is automatically assigned upon the creation of a new document. You can think of the ``_id`` as the document's :term:`primary key`. - lvm + LVM Logical volume manager. LVM is a program that abstracts disk images from physical devices, and provides a number of raw disk manipulation and snapshot capabilities useful for system @@ -477,10 +469,10 @@ Glossary order are identical. primary key - A record's unique, immutable identifier. In an RDBMS, the primary + A record's unique, immutable identifier. In an :term:`RDBMS`, the primary key is typically an integer stored in each row's ``id`` field. In MongoDB, the :term:`_id` field holds a document's primary - key. Primary keys are usually :term:`BSON` Object IDs. + key which is usually a BSON :term:`ObjectId`. unique index An index that enforces uniqueness for a particular field across @@ -496,6 +488,8 @@ Glossary operations in a database's ``system.profile`` collection. The profiler is most often used to diagnose slow queries. + .. seealso:: ":ref:`Monitoring Database Systems `." + shard key In a sharded collection, a shard key is the field that MongoDB uses to distribute documents among members of the @@ -516,14 +510,14 @@ Glossary pre-splitting When deploying a :term:`shard cluster`, it is sometimes necessary to expedite the initial distribution of documents - among shards, by manually dividing the collection into chunks. + among shards by manually dividing the collection into chunks. In this case, you pre-split the chunks instead of waiting for - MongoDB to create splits. + the MongoDB :term:`balancer` to create splits. SSD Solid State Disk. A high-performance disk drive that uses solid - state elecronics, as opposed to rotating platters and a head, for - persistence. + state electronics for persistence, as opposed to the rotating platters + and movable read/write heads used by traditional mechanical hard drives. resident memory The subset of an application's memory currently stored in @@ -535,7 +529,7 @@ Glossary disk an in physical RAM. pipe - A communication channel UNIX allowing independent processes + A communication channel in UNIX-like systems allowing independent processes to send and receive data. In the UNIX shell, piped operations allow users to direct the output of one command into the input of another. @@ -546,7 +540,7 @@ Glossary support the number of hosts on the contemporary Internet. draining - The process of removing, or "shedding" :term:`chunks ` + The process of removing or "shedding" :term:`chunks ` from one :term:`shard` to another. Administrators must drain shards before removing them from the cluster. @@ -586,7 +580,7 @@ Glossary nodes have :term:`eventual consistency`. write concern - A setting on writes to MongoDB that allows the use to specify, + A setting on writes to MongoDB that allows the user to specify, how the database will handle a write operation before returning. This often determines how many :term:`replica set` members should propagate a write before returning. @@ -595,14 +589,14 @@ Glossary priority In the context of :term:`replica sets `, priority - is a configurable values that help determine which nodes in + is a configurable value that helps determine which nodes in a replica set are most likely to become :term:`primary`. .. seealso:: ":ref:`Replica Set Node Priority `" election - In the context of :term:`replica sets `, election + In the context of :term:`replica sets `, an election is the process by which members of a replica set select primary nodes on startup and in the event of failures. @@ -637,7 +631,7 @@ Glossary read preference A setting on the MongoDB :doc:`drivers ` - that determines where how the clients direct read + that determines how the clients direct read operations. Read preference affects all replica sets including shards. By default, drivers direct all reads to :term:`primary` nodes for :term:`strict consistency`. However, you may also @@ -653,7 +647,7 @@ Glossary to keep replication lag as small as possible. driver - A client implementing the communcation protocol required for talking + A client implementing the communication protocol required for talking to a server. The MongoDB drivers provide language-idiomatic methods for interfacing with MongoDB. @@ -686,7 +680,7 @@ Glossary clients may use to issue data-center aware operations. recovering - A :term:`replica set` memeber status indicating that a member + A :term:`replica set` member status indicating that a member is synchronizing or re-synchronizing its data from the primary node. Recovering nodes are unavailable for reads. @@ -709,11 +703,18 @@ Glossary .. STUB ":doc:`/core/map-reduce`" + RDBMS + Relational Database Management System. A database management system based on the relational model, typically using :term:`SQL` as the query language. + SQL - Standard Query Language. SQL is the language used for all - interactions with a relational database. Provides read, write, - and data aggregation capabilities Often, ``SQL`` is often used - as a metonym for relational databases. + Structured Query Language (SQL) is a common special-purpose programming + language used for interaction with a relational database including access + control as well as inserting, updating, querying, and deleting data. + There are some similar elements in the basic SQL syntax supported by different + database vendors, but most implementations have their own dialects, + data types, and interpretations of proposed SQL standards. + Complex SQL is generally not directly portable between major :term:`RDBMS` products. + Often, ``SQL`` is often used as a metonym for relational databases. aggregation Any of a variety of operations that reduce and summarize large @@ -721,9 +722,8 @@ Glossary examples of aggregation functions. aggregation framework - An aggregation command that provides a large set of operators - resembling the MongoDB query language and that's used to perform - common aggregations. + The MongoDB aggregation framework provides a means to calculate + aggregate values without having to use :term:`map-reduce`. .. seealso:: ":doc:`/applications/aggregation`." @@ -749,8 +749,8 @@ Glossary of any database. JavaScript - An popular scripting language original designed for web browers. - The MongoDB's shell, and certain server-side functions, use + A popular scripting language original designed for web browsers. + The MongoDB shell and certain server-side functions use a JavaScript interpreter. idempotent @@ -797,10 +797,10 @@ Glossary TTL Stands for "time to live," and represents an expiration time or period for a given piece of information to remain in a cache or - other temporary storage system before deleted or aged out. + other temporary storage system before being deleted or aged out. ObjectId A special 12-byte :term:`BSON` type that has a high probability of being unique when generated. The most significant digits in an ObjectId represent the time when the Object. MongoDB uses - ObjectId values as the default values for :term:`_id` field. + ObjectId values as the default values for :term:`_id` fields.