In this tutorial, we'll develop a secure poll and voting system using PHP and MySQL. This system will allow you to interact with your audience and display a collection of polls. You'll learn to create polls, implement a voting system, delete polls, and display the list of published polls., 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 , placeholderData can also be a function, where you can get access to the data and Query meta information of a "previous" successful Query. This is useful for situations where you want to use the data from one query as the placeholder data for another query., 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, Prison Placeholder Attributes: Prison supports Placeholder Attributes which allows an infinite way to customize most placeholders, such as numeric formatting, hex colors, and reductions. Can customize any bar-graph for character codes, colors, and size. Simple examples using placeholder attributes with the results following each example. Colors , 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 situations where you have enough partial (or fake) data to render the query successfully while the actual data is fetched in the background..