Assignment 2 1) What is the DBMS functions? Data dictionary management. The DBMS stores definitions of the data elements and their relationships

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1 Assignment 2 1) What is the DBMS functions? Data dictionary management. The DBMS stores definitions of the data elements and their relationships (metadata) in a data dictionary. In turn, all programs that access the data in the database work through the DBMS. DBMS provides data abstraction, and it removes structural and data dependence from the system. Data storage management. The DBMS creates and manages the complex structures required for data storage. Data storage management is also important for database performance tuning. Performance tuning relates to the activities that make the database perform more efficiently in terms of storage and access speed. Data transformation and presentation. The DBMS transforms entered data to conform to required data structures. Example, July 11, 2013, UK as 11/07/2013. USA as 07/11/2013. Security management. The DBMS creates a security system that enforces user security and data privacy. Multiuser access control. To provide data integrity and data consistency, the DBMS uses sophisticated algorithms to ensure that multiple users can access the database concurrently without compromising its integrity. Backup and recovery management. The DBMS provides backup and data recovery to ensure data safety and integrity. Current DBMS systems provide special utilities that allow the DBA to perform routine and special backup and restore procedures. Recovery management deals

2 with the recovery of the database after a failure, such as a bad sector in the disk or a power failure. Data integrity management. The DBMS promotes and enforces integrity rules, thus minimizing data redundancy and maximizing data consistency. The data relationships stored in the data dictionary are used to enforce data integrity. Database access languages and application programming interfaces. The DBMS provides data access through a query language. The DBMS also provides application programming interfaces to procedural languages such as COBOL, C, Java, Visual Basic.NET, and C#. In addition, the DBMS provides administrative utilities used by the DBA and the database designer to create, implement, monitor, and maintain the database. Database communication interfaces. A current- generation DBMS accepts end- user requests via multiple, different network environments. For example, the DBMS might provide access to the database via the Internet through the use of Web browsers such as Mozilla Firefox or Microsoft Internet Explorer. 2) Explain what we mean by data independence list its types and define them? Data independence, which can be defined as the capacity to change the schema at one level of a database system without having to change the schema at the next higher level. We can define two types of data independence:

3 1) Logical data independence: is the capacity to change the conceptual schema without having to change external schemas or application programs. 2) Physical data independence: is the capacity to change the internal schema without having to change the conceptual schema. Hence, the external schemas need not be changed as well. 3) List all the DBMS languages and their definition. In many DBMSs where no strict separation of levels is maintained, one language, called the data definition language (DDL), is used by the DBA and by database designers to define both schemas. In DBMSs where a clear separation is maintained between the conceptual and internal levels, the DDL is used to specify the conceptual schema only. Another language, the storage definition language (SDL), is used to specify the internal schema. For a true three- schema architecture, we would need a third language, the view definition language (VDL), to specify user views and their mappings to the conceptual schema, but in most DBMSs the DDL is used to define both conceptual and external schemas. Typical manipulations include retrieval, insertion, deletion, and modification of the data. The DBMS provides a set of operations or a language called the data manipulation language (DML) for these purposes. There are two main types of DMLs: A high- level or nonprocedural DML can be used on its own to specify complex database operations concisely.

4 Many DBMSs allow high- level DML statements either to be entered interactively from a display monitor or terminal or to be embedded in a general- purpose programming language. A low- level or procedural DML must be embedded in a general- purpose programming language. This type of DML typically retrieves individual records or objects from the database and processes each separately. Therefore, it needs to use programming language constructs, such as looping, to retrieve and process each record from a set of records. Low- level DMLs are also called record- at- a- time DMLs because of this property. 4) List all the DBMS interfaces. Menu- Based Interfaces for Web Clients or Browsing. Forms- Based Interfaces. Graphical User Interfaces. Natural Language Interfaces. Speech Input and Output. Interfaces for Parametric Users. Interfaces for the DBA. 5) What is the domain, relation schema, relation? A domain D is a set of atomic values. A relation schema(sometimes called a relation scheme) R, denoted by R(A 1, A 2,...,A n ), is made up of a relation name R and a list of attributes, A 1, A 2,...,A n. Each attribute A i is the name of a role played by some domain D in the relation schema R. D is called the domain of A i and is denoted by dom(a i ). A relation

5 schema is used to describe a relation; R is called the name of this relation. The degree (or arity) of a relation is the number of attributes n of its relation schema. A relation (or relation state or relation instance) r of the relation schema R(A 1, A 2,...,A n ), also denoted by r(r), is a set of n- tuples r = {t 1, t 2,..., t m }. Each n- tuple t is an ordered list of n values t =<v 1, v 2,..., v n >, where each value v i, 1 i n, is an element of dom(a i ) or is a special NULL value. The i th value in tuple t, which corresponds to the attribute A i, is referred to as t[a i ] or t. A i (or t[i] if we use the positional notation). 6) List all type of keys and their characteristics. A composite key is a key that is composed of more than one attribute. An attribute that is a part of a key is called a key attribute. A superkey is a key that can uniquely identify any row in the table. A candidate key is a minimal superkey that is, a superkey without any unnecessary attributes. A foreign key is the primary key of one table that has been placed into another table to create a common attribute. Secondary key is defined as a key that is used strictly for data retrieval purposes. Primary key is A candidate key selected to uniquely identify all other attribute values in any given row; cannot contain null entries.

6 7) List all type of integrity you have studied in the course their definitions and requirements. 1) ENTITY INTEGRITY: is the condition in which each row (entity instance) in the table has its own unique identity. To ensure entity integrity, the primary key has two requirements: (1) all of the values in the primary key must be unique, and (2) no key attribute in the primary key can contain a null. 2) Referential integrity, the condition in which every reference to an entity instance by another entity instance is valid. In other words, every foreign key entry must either be null or a valid value in the primary key of the related table. Its requirements: A foreign key may have either a null entry, as long as it is not a part of its table s primary key, or an entry that matches the primary key value in a table to which it is related. (Every non- null foreign key value must reference an existing primary key value.) 8) If you have the table below answer these questions:

7 a) Give the result of this selection σ(dno=4 AND Salary>25000) OR (Dno=5 AND Salary>30000) (EMPLOYEE). b) Give the result of this projection πlname, Fname, Salary(EMPLOYEE).

8 c) Give the result of this projection πsex, Salary(EMPLOYEE). d) Give the result of this operation πfname, Lname, Salary(σ Dno=5(EMPLOYEE)).

9 9) Given the tables below answer the Result of the UNION operation RESULT RESULT1 RESULT2.

10 10) Given the tables below answer a) STUDENT INSTRUCTOR.

11 b) STUDENT INSTRUCTOR. c) STUDENT INSTRUCTOR. d) INSTRUCTOR STUDENT.

12 11) Given the tables below answer the following a) FEMALE_EMPS σsex= F (EMPLOYEE). b) EMPNAMES πfname, Lname, Ssn(FEMALE_EMPS).

13 c) EMP_DEPENDENTS EMPNAMES DEPENDENT. d) ACTUAL_DEPENDENTS σssn=essn(emp_dependents). e) RESULT πfname, Lname, Dependent_name(ACTUAL_DEPENDENTS).

14 12) Given the tables below answer the following a) DEPT_MGR DEPARTMENT Mgr_ssn=Ssn EMPLOYEE b) RESULT πdname, Lname, Fname(DEPT_MGR) Dname Lname Fname Research Wong Franklin Administration Wallace Jennifer Headquarters Borg James

15 13) Given the tables below answer the following a) SSNS(Ssn) SSN_PNOS SMITH_PNOS

16 b) T R S

17 14) Given the tables below answer the following a) Give the natural join result where (*) is the natural join operation PROJ_DEPT PROJECT * DEPT b) DEPT_LOCS DEPARTMENT * DEPT_LOCATIONS

18 15) Describe which relation is between a person and his passport, draw the relation with Chen notation, Crow s Foot notation and UML notation; implement the tables with dummy data. Chen Notation Crow s Foot Notation UML Notation

19 Tables Passport Passport_ID Expire_Date Issue_Date Issue_Place Person_ID 1 1/2/2016 1/2/2011 Riyadh 3 2 6/7/2018 6/7/2013 Riyadh 1 3 2/3/2020 2/3/2015 Riyadh 5 4 9/10/2019 9/10/2014 Riyadh 2 5 1/12/2015 1/12/2010 Riyadh 4 Person Person_ID Person_Name National_ID DOB Place_of_Birth 1 Mohammad /5/1981 Riyadh 2 Saud /1/1990 Majmaah 3 Faisal /3/1995 Makkah 4 Ahmad /1/1988 Riyadh 5 Khaled /4/1985 Qassim

20 16) Describe which relation is between a car and its seats, draw the relation with Chen notation, Crow s Foot notation and UML notation; implement the tables with dummy data. Chen Notation Crow s Foot Notation UML Notation

21 Tables Seat Seat_ID Seat_width Seat_hight Seat_color Car_ID Gray Gray Gray Black Red Red Black Black Green Green Green Green Green 4 Car Car_ID Car_Name Car_Number_of_Seats Car_Manufacture_Place 1 Corolla 3 Japan 2 Honda 3 Japan 3 Porsche 2 Germany 911 Carrera 4 Yukon 5 USA

22 17) Describe which relation is between teachers and students in certain school, draw the relation with Chen notation, Crow s Foot notation and UML notation; implement the tables with dummy data. Chen Notation Crow s Foot Notation UML Notation

23 Tables Teachers Teacher_ID Name DOB College Field 1 Mohammad 1/7/1980 Computer Computer Science 2 Ahmad 2/8/1981 Science Mathmetics 3 Saud 2/1/1982 Engineering Electrical Students Student_ID Name DOB College Department 1 Faisal 1/3/1995 Computer IT 2 Khaled 4/5/1996 Science Mathematics 3 Turki 2/1/1997 Engineering Electronics Teachers_Students Teacher_ID Student_ID