2.22.32.42.82.13 2.1 Explain the concept of database schema and discuss the three types of schema in a database. 2.2. What are data sublanguages? Why are they important? 2.3 What is a data model? Discuss the main types of data model. 2.4 Discuss the function and importance of conceptual modeling. 2.5 Describe the types of facility that you would expect to be provided in a multi-user DBMS. 2.6 Of the facilities described in your answer to Question 2.5, which ones do you think would not be needed in a standalone PC DBMS? Provide justification for your answer. 2.7 Discuss the function and importance of the system catalog. 2.8 Discuss the differences between DDL and DML What operations would you typically expect to be available in each language? 2.9 Discuss the differences between procedural DMLs and nonprocedural DMLs. 2.10 Name four object-based data models. 2.11 Name three record-based data models. Discuss the main differences between these data models. 2.12 What is a transaction? Give an example of a transaction. 2.13 What is concurrency control and why does a DBMS need a concurrency control facility? 2.14 Define the term "database integrity". How does database integnity differ from database secunty