The GlideRecord class is one of the most ubiquitous and useful classes in ServiceNow. Its primary function is to query a database table, and present values corresponding to each record in that table, that matches a given query. It can also be used to add, modify, or delete records. A GlideRecord object consists of properties with names corresponding to each field in the table. In the client-side Glide API, these properties usually contain strings, whereas on the server-side API, these properties contain GlideElement JavaScript Objects with their own methods and properties.
A GlideRecord object must first be initialized by using the new keyword (which calls the initialize() constructor method) and passing in a table name as a string. This tells the new GlideRecord object what table any subsequent queries or new records are created on.