A monad on top of m (which must be a MonadIO) that may access the database and may fail with a DB Failure

Run action against database on server at other end of pipe. Use access mode for any reads and writes. Return Left on connection failure or read/write failure.

A connection failure, or a read or write exception like cursor expired or inserting a duplicate key. Note, unexpected data from the server is not a Failure, rather it is a programming error (you should call error in this case) because the client and server are incompatible and requires a programming change.

Error code from getLastError or query failure

Type of reads and writes to perform

Parameters for getLastError command. For example ["w" =: 2] tells the server to wait for the write to reach at least two servers in replica set before acknowledging. See http://www.mongodb.org/display/DOCS/Last+Error+Commands for more options.

Same as ConfirmWrites []

Same as ReadStaleOk

Run action with given AccessMode

Values needed when executing a db operation

List all databases residing on server

Run action against given database

Current database in use

Authenticate with the current database (if server is running in secure mode). Return whether authentication was successful or not. Reauthentication is required for every new pipe.

Collection name (not prefixed with database)

List all collections in this database

Selects documents in collection that match selector

Filter for a query, analogous to the where clause in SQL. [] matches all documents in collection. ["x" =: a, "y" =: b] is analogous to where x = a and y = b in SQL. See http://www.mongodb.org/display/DOCS/Querying for full selector syntax.

Add Javascript predicate to selector, in which case a document must match both selector and predicate

Insert document into collection and return its "_id" value, which is created automatically if not supplied

Same as insert except don't return _id

Insert documents into collection and return their "_id" values, which are created automatically if not supplied. If a document fails to be inserted (eg. due to duplicate key) then remaining docs are aborted, and LastError is set.

Same as insertMany except don't return _ids

Insert documents into collection and return their "_id" values, which are created automatically if not supplied. If a document fails to be inserted (eg. due to duplicate key) then remaining docs are still inserted. LastError is set if any doc fails, not just last one.

Same as insertAll except don't return _ids

Save document to collection, meaning insert it if its new (has no "_id" field) or upsert it if its not new (has "_id" field)

Replace first document in selection with given document

Replace first document in selection with given document, or insert document if selection is empty

Update first document in selection with given document, or insert document if selection is empty

Update operations on fields in a document. See http://www.mongodb.org/display/DOCS/Updating#Updating-ModifierOperations

Update all documents in selection using given modifier

Delete all documents in selection

Delete first document in selection

Use select to create a basic query with defaults, then modify if desired. For example, (select sel col) {limit = 10}

Fields to return, analogous to the select clause in SQL. [] means return whole document (analogous to * in SQL). ["x" =: 1, "y" =: 1] means return only x and y fields of each document. ["x" =: 0] means return all fields except x.

Maximum number of documents to return, i.e. cursor will close after iterating over this number of documents. 0 means no limit.

Fields to sort by. Each one is associated with 1 or -1. Eg. ["x" =: 1, "y" =: -1] means sort by x ascending then y descending

The number of document to return in each batch response from the server. 0 means use Mongo default.

Return performance stats of query execution

Fetch documents satisfying query

Fetch first document satisfying query or Nothing if none satisfy it

Same as findOne except throw DocNotFound if none match

runs the findAndModify command as an update without an upsert and new set to true. Returns a single updated document (new option is set to true).

see findAndModifyOpts if you want to use findAndModify in a differnt way

runs the findAndModify command, allows more options than findAndModify

Fetch number of documents satisfying query (including effect of skip and/or limit if present)

Fetch distinct values of field in selected documents

Iterator over results of a query. Use next to iterate or rest to get all results. A cursor is closed when it is explicitly closed, all results have been read from it, garbage collected, or not used for over 10 minutes (unless NoCursorTimeout option was specified in Query). Reading from a closed cursor raises a CursorNotFoundFailure. Note, a cursor is not closed when the pipe is closed, so you can open another pipe to the same server and continue using the cursor.

Return next batch of documents in query result, which will be empty if finished.

Return next document in query result, or Nothing if finished.

Return next N documents or less if end is reached

Return remaining documents in query result

The Aggregate Pipeline

Runs an aggregate and unpacks the result. See http://docs.mongodb.org/manual/core/aggregation/ for details.

Groups documents in collection by key then reduces (aggregates) each group

Fields to group by, or function (doc -> key) returning a "key object" to be used as the grouping key. Use KeyF instead of Key to specify a key that is not an existing member of the object (or, to access embedded members).

Execute group query and return resulting aggregate value for each distinct key

Maps every document in collection to a list of (key, value) pairs, then for each unique key reduces all its associated values to a single result. There are additional parameters that may be set to tweak this basic operation. This implements the latest version of map-reduce that requires MongoDB 1.7.4 or greater. To map-reduce against an older server use runCommand directly as described in http://www.mongodb.org/display/DOCS/MapReduce.

() -> void. The map function references the variable this to inspect the current object under consideration. The function must call emit(key,value) at least once, but may be invoked any number of times, as may be appropriate.

(key, [value]) -> value. The reduce function receives a key and an array of values and returns an aggregate result value. The MapReduce engine may invoke reduce functions iteratively; thus, these functions must be idempotent. That is, the following must hold for your reduce function: reduce(k, [reduce(k,vs)]) == reduce(k,vs). If you need to perform an operation only once, use a finalize function. The output of emit (the 2nd param) and reduce should be the same format to make iterative reduce possible.

(key, value) -> final_value. A finalize function may be run after reduction. Such a function is optional and is not necessary for many map/reduce cases. The finalize function takes a key and a value, and returns a finalized value.

Result of running a MapReduce has some stats besides the output. See http://www.mongodb.org/display/DOCS/MapReduce#MapReduce-Resultobject

MapReduce on collection with given map and reduce functions. Remaining attributes are set to their defaults, which are stated in their comments.

Run MapReduce and return cursor of results. Error if map/reduce fails (because of bad Javascript)

Run MapReduce and return a MR result document containing stats and the results if Inlined. Error if the map/reduce failed (because of bad Javascript).

A command is a special query or action against the database. See http://www.mongodb.org/display/DOCS/Commands for details.

Run command against the database and return its result

runCommand1 foo = runCommand [foo =: 1]

Run code on server