What is "dao-pattern"

The DAO standard is a design pattern that abstracts and encapsulates the data access mechanisms by hiding the details of data origin execution. This standard allows you to create data classes regardless of the data source being a relational BD, a text file, an XML file, etc. To do this, it encapsulates the mechanisms of access to data and creates a generic client interface to make the access to data allowing the mechanisms of access to data to be changed regardless of the code that uses the data.