# Metadata


Operators and keywords that get or set metadata.

[`attr`](../ref/attr.md)

: Attributes of a list

[`cols`](../ref/cols.md#cols)

: Columns of a table

[`fkeys`](../ref/fkeys.md)

: Foreign keys of a table

[`key`](../ref/key.md)

: Variously: 

    -   Keys of a dictionary
    -   key columns/s of a keyed table
    -   contents of a filesystem directory
    -   whether a file exists
    -   whether a variable name is in use
    -   name of the table linked to by a foreign-key column
    -   type of a vector
    -   name of an enumerating list
    -   a synonym for [`til`](../ref/til.md)

[`keys`](../ref/keys.md#keys)

: Primary key column/s of a table

[`meta`](../ref/meta.md)

: Metadata for a table

[`#` Set Attribute](../ref/set-attribute.md)

: Set the attribute of a list

[`tables`](../ref/tables.md)

: List of tables in a namespace

[`type`](../ref/type.md)

: [Datatype](datatypes.md) of an object

[`.Q.ty`](../ref/dotq.md#ty-type)

: Datatype as a character code

[`value`](../ref/value.md)

: Variously

    -   values of a dictionary
    -   value of a variable passed by name
    -   symbol vector of an [enumeration](enumerations.md)
    -   metadata of a function
    -   metadata of a view
    -   decomposition of a projection or composition
    -   internal code of a primitive
    -   original map of an extension
    -   internal code of a primitive function
    -   the result of applying the first item of a list to the rest of it
    -   the result of evaluating a string


[`view`](../ref/view.md)

: Expression defining a view

[`views`](../ref/view.md#views)

: List of views in the default namespace


[`.Q`](../ref/dotq.md) and
[`.z`](../ref/dotz.md) namespaces