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$bitsAllSet

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  • Behavior
  • Examples
$bitsAllSet

$bitsAllSet matches documents where all of the bit positions given by the query are set (i.e. 1) in field.

{ <field>: { $bitsAllSet: <numeric bitmask> } }
{ <field>: { $bitsAllSet: < BinData bitmask> } }
{ <field>: { $bitsAllSet: [ <position1>, <position2>, ... ] } }

The field value must be either numeric or a BinData instance. Otherwise, $bitsAllSet will not match the current document.

Numeric Bitmask
You can provide a numeric bitmask to be matched against the operand field. The bitmask must be a non-negative 64-bit signed integer. Otherwise, $bitsAllSet returns an error.
BinData Bitmask
You can also use an arbitrarily large BinData instance as a bitmask.
Position List
If querying a list of bit positions, each <position> must be a non-negative integer. Bit positions start at 0 from the least significant bit. For example, the decimal number 254 would have the following bit positions:
Bit Value
1
1
1
1
1
1
1
0
Position
7
6
5
4
3
2
1
0

The endianness of your system depends on the architecture of your machine. Numbers in BSON data are always stored as little-endian, if your system is big-endian this means that numeric data is converted between big and little endian.

In the context of the bit-test match expression operators:

BinData values act as bitmasks and are interpreted as though they are arbitrary-length unsigned little-endian numbers. The lowest-addressable byte is always interpreted as the least significant byte. Similarly, the highest-addressable byte in the BinData is always interpreted as the most significant byte.

Queries cannot use indexes for the $bitsAllSet portion of a query, although the other portions of a query can use indexes, if applicable.

$bitsAllSet will not match numerical values that cannot be represented as a signed 64-bit integer. This can be the case if a value is either too large or too small to fit in a signed 64-bit integer, or if it has a fractional component.

Numbers are sign extended. For example, $bitsAllSet considers bit position 200 to be set for the negative number -5, but bit position 200 to be clear for the positive number +5.

In contrast, BinData instances are zero-extended. For example, given the following document:

db.collection.insertOne({ x: BinData(0, "ww=="), binaryValueofA: "11000011" })

$bitsAllSet will consider all bits outside of x to be clear.

The following examples will use a collection with the following documents:

db.collection.insertMany([
{ _id: 1, a: 54, binaryValueofA: "00110110" },
{ _id: 2, a: 20, binaryValueofA: "00010100" },
{ _id: 3, a: 20.0, binaryValueofA: "00010100" },
{ _id: 4, a: BinData(0, "Zg=="), binaryValueofA: "01100110" }
])

The following query uses the $bitsAllSet operator to test whether field a has bits set at position 1 and position 5, where the least significant bit is position 0.

db.collection.find( { a: { $bitsAllSet: [ 1, 5 ] } } )

The query matches the following documents:

{ "_id" : 1, "a" : 54, "binaryValueofA" : "00110110" }
{ "_id" : 4, "a" : BinData(0,"Zg=="), "binaryValueofA" : "01100110" }

The following query uses the $bitsAllSet operator to test whether field a has bits set at positions 1, 4, and 5 (the binary representation of the bitmask 50 is 00110010).

db.collection.find( { a: { $bitsAllSet: 50 } } )

The query matches the following document:

{ "_id" : 1, "a" : 54, "binaryValueofA" : "00110110" }

The following query uses the $bitsAllSet operator to test whether field a has bits set at positions 4 and 5 (the binary representation of BinData(0, "MA==") is 00110000).

db.collection.find( { a: { $bitsAllSet: BinData(0, "MA==") } } )

The query matches the following document:

{ _id: 1, a: 54, binaryValueofA: "00110110" }
← $bitsAllClear

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