# Query Library
## Features
The main function of the query \*\*\*\* library is to create and manage reusable queries:
* Writing queries based on data sources, with the ability to define **Inputs** variables.
* Importing and triggering queries from query library in apps and modules.
### Input parameters
There are cases where you want to pass dynamic parameters to a query. Appizap supports that by introducing input configuration of a query.
Click **Add** in the **Inputs** tab in the right pane to add input parameters. Reference them using `{{}}` in the query, then you can input test values to test execution of the query.
{% hint style="warning" %}
You can only reference variables instead of writing JavaScript code in `{{}}`.
{% endhint %}
To edit the name and description of the input variables, click `...` and select **Edit** or directly click the title of the variable.
## Version management
Queries may be updated on demand. You can make an adjustment to a query to a newer version and at the same time maintain the older version. Such version management is achievable in query library. Click `···` in the top right corner to publish different versions of queries, and you can view and restore history versions.
### Publish
When you finish writing a version of the query, you can publish it. Click `···` > **Publish**. Use [semantic versioning](https://semver.org/) (also known as SemVer) to name your version.
### History version
To view and restore the history versions, go to `···` > **History version**.
You can restore your current draft to a history version by selecting the target version from the history version list and clicking **Restore this version**. Click **Exit** to return to edit mode.
## Permissions
Workspace **Admin** and members of **Developers** group have access to the **Query Library** and have read and write permissions to all queries in the library.
