Mutation Rewrites
This section describes the DDL commands pertaining to mutation rewrites.
Create rewrite
Define a new mutation rewrite.
When creating a new property or link:
{create | alter} type type-name "{"
create { property | link } prop-or-link-name -> type "{"
create rewrite {insert | update} [, ...]
using expr
"}" ;
"}" ;When altering an existing property or link:
{create | alter} type type-name "{"
alter { property | link } prop-or-link-name "{"
create rewrite {insert | update} [, ...]
using expr
"}" ;
"}" ;Description
The command create rewrite nested under create type or alter type
and then under create property/link or alter property/link defines a
new mutation rewrite for the given property or link on the given object.
Parameters
- type-name
-
The name (optionally module-qualified) of the type containing the rewrite.
- prop-or-link-name
-
The name (optionally module-qualified) of the property or link being rewritten.
- insert | update [, ...]
-
The query type (or types) that are rewritten. Separate multiple values with commas to invoke the same rewrite for multiple types of queries.
Examples
Declare two mutation rewrites on new properties: one that sets a created
property when a new object is inserted and one that sets a modified
property on each update:
alter type User {
create property created -> datetime {
create rewrite insert using (datetime_of_statement());
};
create property modified -> datetime {
create rewrite update using (datetime_of_statement());
};
};Drop rewrite
Remove a mutation rewrite.
alter type type-name "{"
alter property prop-or-link-name "{"
drop rewrite {insert | update} ;
"}" ;
"}" ;Description
The command drop rewrite inside an alter type block and further inside
an alter property block removes the definition of an existing mutation
rewrite on the specified property or link of the specified type.
Parameters
- type-name
-
The name (optionally module-qualified) of the type containing the rewrite.
- prop-or-link-name
-
The name (optionally module-qualified) of the property or link being rewritten.
- insert | update [, ...]
-
The query type (or types) that are rewritten. Separate multiple values with commas to invoke the same rewrite for multiple types of queries.
Example
Remove the insert rewrite of the created property on the User type:
alter type User {
alter property created {
drop rewrite insert;
};
};