It is possible to create persistent and transient maps. The lifetime of a transient map is limited by the execution of the current query. A persistent map lives until it is explicitly dropped. Accordingly, it is also available to other requests.
For example,
map:create("my-map", ["string", "integer"], { "persistent" : false })
will create a transient map named my-map having two keys.
The types of the keys are string and integer.
The key of a particular entry in the map can consist of a tuple of atomic values (called key attributes). The actual type of each attribute is determined when the map is created. The value of each entry is a sequence of items. If an item in this sequence is a object or array, this item needs to belong to a collection, otherwise, an error is raised.
available-maps
() as string* external
The function returns a sequence of names of the maps that are available (persistent and non-persistent). |
create
($name as string, $key-types as item()) as empty-sequence() external
Create a persistent map with a given name and type identifiers for the key attributes. |
create
($name as string, $key-types as item(), $options as object()) as empty-sequence() external
Create a map with a given name, type identifiers for the key attributes, and options. |
delete
($name as string, $key as item()) as empty-sequence() external
Removes an entry identified by the given key from the map. |
drop
($name as string) as empty-sequence() external
Deletes the map with the given name. |
get
($name as string, $key as item()) as item()* external
Returns the value of the entry with the given key from the map. |
insert
($name as string, $key as item(), $value as item()*) as empty-sequence() external
Inserts a new entry into the map with the given name. |
keys
($name as string) as array()* external
Returns the keys of all entries of a map. |
options
($name as string) as object() external
The function returns the options that were passed during creation or the default options if no options were passed. |
size
($name as string) as integer external
Returns the number of entries in a map. |
declare function map:available-maps() as string* external
declare %an:sequential function map:create($name as string, $key-types as item()) as empty-sequence() external
If the map has only one key attribute, a single type identifier is given,
for more than one key attribute an array of type identifiers is given.
Calling this function is equivalent to calling create with the options
{ "persistent" : true }
Note that the function is sequential and immediately creates the map.
Each key-type should be specified as string (e.g. "integer", "string", "boolean", "double", or "datetime").
For example,
map:create("my-map", "string") or
map:create("my-map", ["string", "integer"]).
declare %an:sequential function map:create($name as string, $key-types as item(), $options as object()) as empty-sequence() external
If the map has only one key attribute, a single type identifier is given,
for more than one key attribute an array of type identifiers is given.
Currently only one option is supported: To create a transient map the object
{ "persistent" : false }
has to be passed to the $options parameter.
Note that the function is sequential and immediately creates the map in the
store.
Note that a map cannot be created if it already exists in a parent context.
For example, a map that was created in an outer query cannot be
created again in an inner query executed using the
reflection:eval-s function.
declare %an:sequential function map:delete($name as string, $key as item()) as empty-sequence() external
If the map has only one key attribute, a single key value is given, for more than one key attribute an array of key values is given.
Note that it is possible to insert entries with empty key attributes. However as the removing the entries is based on the "eq" comparison and as "eq" with an empty sequence always return false, it is not possible to delete these entries.
declare %an:sequential function map:drop($name as string) as empty-sequence() external
Note that a map can only be dropped in the context it was created.
For example, a map that was created in an outer query cannot be
dropped in an inner query executed using the
reflection:eval-s function.
declare function map:get($name as string, $key as item()) as item()* external
If the map has only one key attribute, a single key value is given, for more than one key attribute an array of key values is given.
Note that it is possible to insert entries with empty key attributes. However as the getting the entries is based on the "eq" comparison and as "eq" with an empty sequence always return false, it is not possible to retrieve these entries.
For example,
map:get("my-map", "key") or
map:get("my-map", [ "key1", "key2" ]).
declare %an:sequential function map:insert($name as string, $key as item(), $value as item()*) as empty-sequence() external
If the map has only one key attribute, a single key value is given, for more than one key attribute an array of key values is given. If an entry with the given key already exists in the map, the value sequences of the existing entry and the sequence passed using $value argument are concatenated.
If an item in the value sequence is an object or array, this item needs to belong to a collection, otherwise, an an error is raised.
Note that it is possible to insert entries with empty key attributes
or key attributes having the value null. However, as
the comparison with an empty sequence or null always returns false,
it is not possible to retrieve these entries.
For example,
map:insert("my-map", "key", "value") or
map:insert("my-map", [ "key1", "key2" ] , (42, "value")).
declare function map:keys($name as string) as array()* external
The following condition always holds: map:size($name) eq count(map:keys($name))
declare function map:options($name as string) as object() external
declare function map:size($name as string) as integer external
The following condition always holds: map:size($name) eq count(map:keys($name))
$map:PERSISTENT as string