Indexed

View Source Indexed.View (Indexed v0.3.4)

A data structure about a view, held in ETS.

While prefilters may be defined statically when warming an index, views also define prefilters, but they are tailor-made result sets which can be created and destroyed throughout the Indexed.t/0 lifecycle.

Views define a prefilter to base its result set on. (nil is acceptable for full result set.) Then, a :filter function is used to further narrow the results.

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Types

fingerprint()

A fingerprint is by taking the relevant parameters which were used to construct the prefilter (if applicable) and filter function. This string is used to identify the particular view in the map returned by under the key named by Indexed.views_key/1.

t()
  • :filter - A function which takes a record and returns a truthy value if it should be included in the result set. Required.
  • :maintain_unique - List of field name atoms for which a list of unique values under the view will be managed. These lists can be fetched via Indexed.get_uniques_list/4 and Indexed.get_uniques_map/4.
  • :params - Original user params for building :filter and :prefilter. These are kept mainly for authorization checking in the depending application.
  • :prefilter - The base prefilter from which the :filter further refines. nil for the full record set.
views_map()

Maps fingerprints to view structs. Stored in the index key returned by Indexed.views_key/1.

Functions

fingerprint(params)

Create a unique identifier string for params.

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fingerprint()

View Source 
@type fingerprint() :: String.t()

A fingerprint is by taking the relevant parameters which were used to construct the prefilter (if applicable) and filter function. This string is used to identify the particular view in the map returned by under the key named by Indexed.views_key/1.

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t()

View Source 
@type t() :: %Indexed.View{
  filter: Indexed.filter(),
  maintain_unique: [atom()],
  params: keyword(),
  prefilter: Indexed.prefilter()
}
  • :filter - A function which takes a record and returns a truthy value if it should be included in the result set. Required.
  • :maintain_unique - List of field name atoms for which a list of unique values under the view will be managed. These lists can be fetched via Indexed.get_uniques_list/4 and Indexed.get_uniques_map/4.
  • :params - Original user params for building :filter and :prefilter. These are kept mainly for authorization checking in the depending application.
  • :prefilter - The base prefilter from which the :filter further refines. nil for the full record set.
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views_map()

View Source 
@type views_map() :: %{required(fingerprint()) => t()}

Maps fingerprints to view structs. Stored in the index key returned by Indexed.views_key/1.

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fingerprint(params)

View Source 
@spec fingerprint(keyword() | map()) :: String.t()

Create a unique identifier string for params.

This is not used internally, but is intended as a useful tool for a caller for deciding whether to use an existing view or create a new one. It is expected that params would be used to create the prefilter and/or filter function.