You can imagine that such a query could quickly get complicated, because we would need to repeat the fields at least once - one for each side of the comparison. That's why GraphQL includes reusable units called fragments. Fragments let you construct sets of fields, and then include them in queries where you need to. Here's an example of how you could solve the above situation using fragments:. You can see how the above query would be pretty repetitive if the fields were repeated.
The concept of fragments is frequently used to split complicated application data requirements into smaller chunks, especially when you need to combine lots of UI components with different fragments into one initial data fetch. It is possible for fragments to access variables declared in the query or mutation. See variables. Up until now, we have been using a shorthand syntax where we omit both the query keyword and the query name, but in production apps it's useful to use these to make our code less ambiguous.
The operation type is either query , mutation , or subscription and describes what type of operation you're intending to do. The operation type is required unless you're using the query shorthand syntax, in which case you can't supply a name or variable definitions for your operation. The operation name is a meaningful and explicit name for your operation. It is only required in multi-operation documents, but its use is encouraged because it is very helpful for debugging and server-side logging.
In the same way, GraphQL query and mutation names, along with fragment names, can be a useful debugging tool on the server side to identify different GraphQL requests. So far, we have been writing all of our arguments inside the query string. But in most applications, the arguments to fields will be dynamic: For example, there might be a dropdown that lets you select which Star Wars episode you are interested in, or a search field, or a set of filters. It wouldn't be a good idea to pass these dynamic arguments directly in the query string, because then our client-side code would need to dynamically manipulate the query string at runtime, and serialize it into a GraphQL-specific format.
Instead, GraphQL has a first-class way to factor dynamic values out of the query, and pass them as a separate dictionary.
These values are called variables. Now, in our client code, we can simply pass a different variable rather than needing to construct an entirely new query. This is also in general a good practice for denoting which arguments in our query are expected to be dynamic - we should never be doing string interpolation to construct queries from user-supplied values. It works just like the argument definitions for a function in a typed language.
What you should already know
All declared variables must be either scalars, enums, or input object types. So if you want to pass a complex object into a field, you need to know what input type that matches on the server. Learn more about input object types on the Schema page. Variable definitions can be optional or required.
Grammar and Punctuation: Sentence Fragments - Aims Community College
In the case above, since there isn't an! But if the field you are passing the variable into requires a non-null argument, then the variable has to be required as well. To learn more about the syntax for these variable definitions, it's useful to learn the GraphQL schema language. The schema language is explained in detail on the Schema page.
Default values can also be assigned to the variables in the query by adding the default value after the type declaration. When default values are provided for all variables, you can call the query without passing any variables.
Fragments and run-ons
If any variables are passed as part of the variables dictionary, they will override the defaults. We discussed above how variables enable us to avoid doing manual string interpolation to construct dynamic queries.
- Improve your Primary School Through Drama.
- World / Fragments · GitLab.
- The Testing of Archie Rathbone.
- Livres Animes du Papier au Numerique (French Edition).
- Fragments 12222.
Passing variables in arguments solves a pretty big class of these problems, but we might also need a way to dynamically change the structure and shape of our queries using variables. For example, we can imagine a UI component that has a summarized and detailed view, where one includes more fields than the other. Try editing the variables above to instead pass true for withFriends , and see how the result changes. We needed to use a new feature in GraphQL called a directive. A directive can be attached to a field or fragment inclusion, and can affect execution of the query in any way the server desires.
The core GraphQL specification includes exactly two directives, which must be supported by any spec-compliant GraphQL server implementation:. Directives can be useful to get out of situations where you otherwise would need to do string manipulation to add and remove fields in your query. Server implementations may also add experimental features by defining completely new directives.
Most discussions of GraphQL focus on data fetching, but any complete data platform needs a way to modify server-side data as well. In REST, any request might end up causing some side-effects on the server, but by convention it's suggested that one doesn't use GET requests to modify data.
Fragments and Run-ons
GraphQL is similar - technically any query could be implemented to cause a data write. These example sentences are selected automatically from various online news sources to reflect current usage of the word 'fragment. Send us feedback. See more words from the same century.
More Definitions for fragment. See the full definition for fragment in the English Language Learners Dictionary. Rhyming Dictionary: Words that rhyme with fragment. Spanish Central: Translation of fragment. Nglish: Translation of fragment for Spanish Speakers. Britannica English: Translation of fragment for Arabic Speakers. What made you want to look up fragment? Please tell us where you read or heard it including the quote, if possible. Test Your Knowledge - and learn some interesting things along the way.
Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free! Getting a handle on some usage advice. Some parents can act like animals or machines.
Are you watching or missing something? You all would not have guessed some of these. Some imitative words are more surprising than others. How to use a word that literally drives some people nuts.
- Recognize a fragment when you see one..
- Fragments - Enamine!
- Rules for Finding and Fixing Fragments?
- What is a Sentence Fragment?.
- Instant Windows PowerShell.
- The Makeup Artist Handbook: Techniques for Film, Television, Photography, and Theatre.
- Pantyhose Dreams, Nylon Fetish Fantasies, USA Edition;
The awkward case of 'his or her'. Test your knowledge of words related to the season of longer days and vacations. Test your knowledge - and maybe learn something along the way. Synonyms for fragment Synonyms: Noun bit , fraction , piece , scrap Synonyms: Verb break , break up , bust , disintegrate , dismember , disrupt , fracture , rive Visit the Thesaurus for More.
Copyright 2019 - All Right Reserved