Why are data connectivity technologies required? What are their functions? $-$ Data connectivity technologies are required by the applications to link the database and access the data stored in the database at runtime. Firstly, a connection to the database is set up that can be used to read$/$write data onto the database. The functions of data connectivity technologies include maintaining the connection to the database as per the provided configurations, to keep the connection open during the execution of the application and allow the application to query the database with ease using standard query languages like SQL$,$ etc.What are the functions of SQL and XML$?$ Describe from your research. $-$ SQL $($Standard Query Language$)$ is a language used to communicate with the database in the relational database management systems. It contains statements that can executed on the relational database management systems to perform the operations like Create, Update, Read, Delete, Append, etc. XML $($Extensible Markup Language$)$ is a simple text file to store and transmit data. XML files are independent of platform or technology and are used in vast applications to store the data in the format which is easy for the programs to read and transmit.Object Linking and Embedding, Database $($OLE DB$)-$ It is a group of API's $($Application Programming Interface$)$ provided by Microsoft to facilitate the access to data from various sources like spreadsheets, SQL based DBMS$,$ personal databased and indexed$-$sequential files.Open Database Connectivity $($ODBC$)-$ It is a standard API to allow access to the database. It is supported by Microsoft for providing components. ODBC is a database language independent that handles the SQL and converting it in the language understood by the database.Java Database Connectivity $($JDBC$)-$ It is a Java API to connect and execute the query with the database.ActiveX Data Objects $($ADO$)-$ It is API from Microsoft that helps programmers to connect and access data from Windows Applications to a relational or non$-$relational database provided by Microsoft as well as any other database provider.ADO.NET $-$ It is a data access technology from the $.$Net framework provided by Microsoft. It is a higher version ADO and provides a lot more flexibility and robustness to access the relational and non$-$relational databases.The SQLCONNECT$()$ and SQLSTRINGCONNECT$()$ functions are used to make the connection to the Recital Database Gateway. Both of these functions can make use of a Recital Database Gateway definition file.