React-Query’s useQuery hook provides several powerful options that can help you build flexible and efficient data-fetching solutions in your React applications. Whether you need to poll an API at a regular interval, fetch data in the background, or transform the data before it’s returned to the component, options like refetchInterval , Does this replace [Redux, MobX, etc]? Migrating to React Query 3. Examples, We make use of Placeholder in forms, to show data related to the entity. For example let's say we have an EditUser page and form. We are using Placeholder as an example while viewing this page, to show some interesting live updating status about some thing based on this user., If set, this value will be used as the placeholder data for this particular query observer while the query is still in the loading data and no initialData has been provided. placeholderData is not persisted to the cache, You must not put the ? parameter placeholders inside a quoted SQL string literals in your query. Parameters are an alternative to using string literals. I would write the query like this: SELECT DISTINCT r.restname FROM restaurants r JOIN food f ON f.restid = r.restid JOIN drinks d ON d.restid = r.restid WHERE f.foodcategory LIKE ?, What is placeholder data? Placeholder data allows a query to behave as if it already has data, similar to the initialData option, but the data is not persisted to the cache. This comes in handy for si.