|     2001 | CSCI   | 4333   | Design of Database Systems          |       3 | The structures usually do not change much, just like the structure of a building. | Daniel   | Kim      | Computer Information Systems | Professor           | | ACCT     | Accounting                   | Relations in mathematics are sets of tuples. | 100005 |   10004 | A-    |        0 | mysql> SELECT DISTINCT deptName, numFaculty The basic relational data model in layman terms: A database is composed of a collection of tables (relations). <> -- conceptually join to form a large table | CINF     | Computer Information Systems | +-------+-------+ | schoolCode | schoolName                    |     -> AND `rank` = 'Associate Professor'; [3] Output fields: lname, fname, SELECT DISTINCT s.lname, s.fname -- [3] Show the names and credits of students majoring in 'MATH'. mysql> If there is a combination of two or more attributes which is being used as the primary key then we call it as a Composite key. 8 rows in set (0.00 sec). Concepts. 11 rows in set (0.00 sec) e.g;, if we update a row from BRANCH with BRANCH_CODE ‘CS’ to ‘CSE’, the rows in STUDENT relation with BRANCH_CODE CS (ROLL_NO 1 and 2 in this case) will be updated with BRANCH_CODE ‘CSE’. Relational Schema: Schema represents structure of a relation. 10 rows in set (0.00 sec), [1] Sources: student An enrollment record may represent a relationship: a student taking a class. +------------+-------------+------+-----+---------+-------+ Do not reverse the order. | 100001 |   10001 | A-    |        0 | | B-    |     2.6667 | |  1012 | Mary   | Tran   | CSCI     | Associate Professor | +-------+------------+ +----------+------------------------------+------------+------------+ mysql> -- Department codes and their names List the last names and first names of students minoring in CINF and having 1011 as faculty advisor. 35. n-ary Relation Table with . | 100006 |   10004 | C+    |     NULL | In this guide, we will discuss what is Relational algebra and relational calculus and why we use these concepts. All student names and the major codes. To distinguish the two version of mysql command line prompt, you may define: "C:\Program Files\MySQL\MySQL Server 8.0\bin\mysql.exe" -P 3308 %*. RELATIONAL MODEL. +--------+--------+ Relational Data Model Introduction 1. The relational calculus in DBMS uses specific terms such as tuple and domain to describe the queries. | 100002 |   10003 | D     |        4 | Introduction to Relational Databases Peter Bazeley BIPG 540/740. Rows. 11 rows in set (0.00 sec) | ACCT     | Accounting                   | BUS        |         10 | +----------+------------------------------+------------+------------+ | MATH     | Mathematics                  | CSE        |          7 | | 100004 | Larry     | Johnson | ITEC  |       |      66 |    1017 | +----------+--------+--------+-------------------------------------+---------+ The Relational Database Model is managed and accessed by a software called a relational database management system. | ARTS     | Arts                         | HSH        |          5 | 3. 2 Chapter 2 Introduction to the Relational Model 2.3 Consider the time slot relation. Overview DBMS vs. Flat Files The Relational Model     ->     department.deptName, faculty.`rank` Some advantages of the relational model and relational DBMS: Data independence: separation of the logical and physical databases. | 100000 |   10003 | C     |        0 | | 100000 |   10001 | A     |        2 | CPS 430/542 Lecture notes: Introduction to the Relational Database Model. This course is an introduction to the basic concepts, organization, and implementation models of databases, with an emphasis on the relational model. | 100009 | Linda     | King    | ARTS  | CSCI  |     125 |    1018 | | ENGL     | English                      | HSH        |         12 | |   10001 |     2001 | Fall     | 2019 |  1011 | D242 | Relational data model is the primary data model, which is used widely around the world for data storage and processing. | 100002 |   10002 | B+    |        2 | | 100008 | Bill      | Ching   | ARTS  | ENGL  |      90 |    1018 | | 100000 |   10002 | B+    |        1 | MySQL creation script: Createtoyu.sql.txt. Relations (or tables) store information about the world Attribute (or column) is a property of a specific object represented by a relation Tuple (or row) is a specific object stored in a relation. | CSCI     | Computer Science             | Thus, you may consider the relation schema and column domains the 'structure' of the database. | C-    |     1.6667 | |     2080 | ARTS   | 3311   | Hindu Arts                          |       3 | 1. information on student is stored in a relation with | 100003 | Catherine | Lim     | ITEC  | CINF  |      20 |    1017 | | 100000 | Tony      | Hawk    | CSCI  | CINF  |      40 |    1011 | The enrollment table is related to the student table through stuId: The standard query language for RDBMS is Structured Query Language (SQL). SELECT DISTINCT s.lname, s.fname Those set of attributes is called key. They may mean: the relation schema: the 'structure' of the table. Relational Frame Theory (RFT) has made a very respectable empirical and theoretical showing in the psychological literature during the past decade, but the theory still remains unknown or unappreciated by most cognitive and behavioral psychologists. A relation is nothing but a table of values. (1995)].     -> WHERE deptCode = 'CSCI'; The output of each operator is a relation: a set of tuples. The relational data model is the most widely used data model, and a vast majority of current database systems are based on the relational model. Each relation should have a primary ket. +------------+-------------------------------+ mysql> Relational model (relational algebra, tuple calculus), Database design (integrity constraints, normal forms), File structures (sequential files, indexing, B and B+ trees). | 100008 | Bill      | Ching   | ARTS  | ENGL  |      90 |    1018 | mysql> SELECT * FROM faculty; The Relational Model is based on two simple concepts:. A relation is a … | ARTS     | Arts                         | HSH        |          5 | Introduction to Relational Data Model - Learning Outcomes; 2. A relation is unordered set that contain the relationship of attributes that represent entities. In a relational database, these are represented as tables. |     2021 | CINF   | 4320   | Web Application Development         |       3 | | 100001 | Mary      | Hawk    | CSCI  | CINF  |      35 |    1011 | +--------+--------+ | Sharon   | Mannes   | Computer Science             | Assistant Professor | 5. In a relational data model, every table needs to have one column or attribute that uniquely identifies a row. Examples: Domain may be understood as the values allowed by the. The NeuroAffective Relational Model (NARM) is a method of psychotherapy specifically aimed at treating attachment, relational and developmental trauma, otherwise referred to as “Complex Trauma” (Complex-PTSD or C-PTSD). Attention reader! +----------+----------+------------------------------+---------------------+ Chapter 2: Intro to Relational Model * * * * * * * * * * * * Example of a Relation attributes (or columns) tuples (or rows) Attribute Types The set of allowed values for each attribute is called the domain of the attribute Attribute values are (normally) required to be atomic; that is, indivisible The special value null is a member of every domain. If there is a violation in any of constrains, operation will fail. Show the student names and their major names for all students who have received a grade A in a class offered by a faculty from the MATH department. +--------+-----------+---------+-------+-------+---------+---------+ It allows easier setup for Web application development. 8 rows in set (0.00 sec), +---------+-----------+| lname   | fname     |+---------+-----------+| Hawk    | Tony      || Hawk    | Mary      || Hawk    | David     || Lim     | Catherine || Johnson | Larry     || Johnson | Linda     || Johnson | Lillian   || Zico    | Ben       || Ching   | Bill      || King    | Linda     |+---------+-----------+ Please write to us at contribute@geeksforgeeks.org to report any issue with the above content. +----------+------------------------------+------------+------------+ | ITEC     | Information Technology       | CSE        |          4 | Following these steps in order. +----------+------------------------------+ Relational Data Model¶. |   11000 |     2000 | Spring   | 2020 |  1011 | D241 | +-------+------------+ Tables − In relational data model, relations are saved in the format of Tables. INSERT INTO department VALUES ('PHYS', 'Physics','CSE',3); The new relation instance of the table department: mysql> select * from department; | 100000 |   11001 | D     |        4 | | MATH     | Mathematics                  | CSE        |          7 | DBMS Relational Model concept with DBMS Overview, DBMS vs Files System, DBMS Architecture, Three schema Architecture, DBMS Language, DBMS Keys, DBMS Generalization, DBMS Specialization, Relational Model concept, SQL Introduction, Advantage of SQL, DBMS Normalization, Functional Dependency, DBMS Schedule, Concurrency Control etc. Basic Operators in Relational Algebra |   10005 |     2040 | Fall     | 2019 |  1015 | D237 | mysql> SELECT DISTINCT fname, lname Free Access. |  1011 | Paul   | Smith  | CSCI     | Professor           | HeidiSQL: general purpose SQL client work with many RDBMS servers. | stuId  | fname     | lname   | major | minor | credits | advisor | Domain: It contains a … ; It is important to recognize the … |  1018 | Art      | Allister | ARTS     | Assistant Professor | |  1019 | Benjamin | Yu       | ITEC     | Lecturer            | • Leading (commercial) manufacturers of relational DB-products: • The notion "relational" is motivated by the mathematical concept of a relation. ; Relational Schema of STUDENT relation can be represented as: STUDENT (STUD_NO, STUD_NAME, STUD_PHONE, STUD_STATE, STUD_COUNTRY, STUD_AGE) (Logical) Data models defines how data is organized, connected, processed and queried conceptually. Domain Constraints: These are attribute level constraints. Given that a particular time slot can meet more than once in a week, explain why day and start time are part of the primary key of this relation, while end time is not. | 100005 |   10005 | A-    |        0 | Introduction to the Relational Model and SQL 62 Overview 1. +-------+--------+--------+----------+---------------------+ +----------+------------------------------+------------+------------+ Get hold of all the important CS Theory concepts for SDE interviews with the CS Theory Course at a student-friendly price and become industry ready. mysql> -- department names and ranks. Coverage: [FCDB] §§3.1-3.3 (pp. mysql> -- Faculty information from the department 'CSCI' Early models included the hierarchical model (where files are related in a parent/child manner, with each child file having at most one parent file), and the network model (where files are related as owners and members, similar to the network model except that each member file can have more than one owner). Relational Model was proposed by E.F. Codd to model data in the form of relations or tables. mysql> -- Names of all faculty members and their |  1012 | Mary     | Tran     | CSCI     | Associate Professor | A relational database is based on the relational model developed by E.F. Codd. +----------+------------------------------+------------+------------+. | schoolCode | varchar(3)  | YES  | MUL | NULL    |       | Each column has a specific data type. from By using our site, you <>, Using toyu: |  1017 | Deborah  | Gump     | ITEC     | Professor           | Author: E. F. Codd. 2. Historical Remarks. | 100000 |   10001 | A     |        2 | +----------+--------+--------+-------------------------------------+---------+ Relational Data Model¶. | MATH     | Mathematics                  | CSE        |          7 | +------------+-------------+------+-----+---------+-------+ +------------------+------------+ 2 Chapter 2 Introduction to the Relational Model 2.3 Consider the time slot relation. where | D-    |     0.6667 | It is important to recognize the basic data structures used by these models. | Hawk  | Tony  | +--------+-----------+---------+-------+-------+---------+---------+ Introduction to version 2 of the relational model. |   11001 |     2001 | Spring   | 2020 |  1013 | D242 | | deptCode | deptName                     | schoolCode | numFaculty | |     2061 | ENGL   | 1311   | English II                          |       3 | +------------------+------------+ | Hawk  | Mary  | There are many data models employed by database systems. Show all information of students majoring in ‘MATH’. mysql> -- department names and ranks in the school CSE | stuId  | fname     | lname   | major | minor | credits | advisor | 3 Faloutsos 15-415 2 Outline • Introduction • Integrity constraints (IC) • Enforcing IC • Querying Relational Data • ER to tables • Intro to Views • Destroying/altering tables Faloutsos 15-415 3 Why Study the Relational Model? | CINF     | Computer Information Systems | CSE        |          5 | Relational Model was proposed by E.F. Codd to model data in the form of relations or tables. Authors Info & Affiliations ; Relational Model. +--------+---------+-------+----------+ 22 rows in set (0.00 sec). After designing the conceptual model of Database using ER diagram, we need to convert the conceptual model in the relational model which can be implemented using any RDMBS languages like Oracle SQL, MySQL etc. mysql> -- Associate professor names from the department 'CSCI' ; ROLL_NO in STUDENT is a key. Relational model is very common among modern database systems in the industry, including MySQL, Microsoft SQL Server, IBM DB2, Microsoft Access, Oracle DB, and PostgreSQL. So a key has two properties: Referential Integrity: When one attribute of a relation can only take values from other attribute of same relation or any other relation, it is called referential integrity. |   10007 |     2060 | Fall     | 2019 |  1020 | B101 | For Maria DB in XAMPP: It is usually "C:\xampp\mysql\bin\mysql.exe". Introduction to Data Analytics for Business TOPIC: Online store department (e- commerce) Part 2: Relational data |   10000 |     2000 | Fall     | 2019 |  1011 | D241 |     -> WHERE faculty.deptCode = department.deptCode; Show the names, major names, and advisor names of every student. e.g,; If a constrains AGE>0 is applied on STUDENT relation, inserting negative value of AGE will result in failure. |  1013 | David  | Love   | CSCI     |                     | FROM student s; →Values are (normally) atomic/scalar. Each table of the column has a name or attribute. +----------+--------+------------------------------+---------------------+ Relational database theory, originally proposed by Edgar F. Codd in 1969, is a topic in Computer Science. On the other hand, the content of a table (called a relation instance) can be changed from time to time. There are many data models employed by database systems. This model is simple and it has all the properties and capabilities required to process data with storage efficiency. It is an introductory course in a series of self-paced courses focusing on databases and related technology, and based on “Databases”, one of Stanford's three inaugural massive open online courses released in the fall of 2011. Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above. +--------+-----------+---------+-------+-------+---------+---------+ +-------+-------+ Show the code of departments with faculty in the rank of 'Professor'. | Jorginlo | Neymar   | Accounting                   | Assistant Professor | | Accounting       |         10 | | 100005 |   10003 | NULL  |     NULL | | 100005 | Linda     | Johnson | CINF  | ENGL  |      13 |    1015 | | ITEC     | Information Technology       | SUPER KEYS: The Relational Model is the most popular of the logic data models, and it’s at the basis of SQL databases.. | David    | Love     | Computer Science             |                     | | B+    |     3.3333 | Relational Data Model in DBMS: Concepts, Constraints, Example | 100002 |   10002 | B+    |        2 | | Field      | Type        | Null | Key | Default | Extra |     -> WHERE faculty.deptCode = department.deptCode e.g; if we try to delete tuple from BRANCH having BRANCH_CODE ‘CS’, it will result in error because ‘CS’ is referenced by BRANCH_CODE of STUDENT, but if we try to delete the row from BRANCH with BRANCH_CODE CV, it will be deleted as the value is not been used by referencing relation. MySQL Command Line Client Prompt: text-based. Two tables may be 'connected' through unique identifiers, known as. 14 rows in set (0.00 sec) An attribute can only take values which lie inside the domain range. | Katrina  | Bajaj    | English                      | Lecturer            | Dr. Soper gives a lecture on the relational model and its role in the database world. ON UPDATE CASCADE: It will update the REFERENCING ATTRIBUTE in REFERENCING RELATION if attribute value used by REFERENCING ATTRIBUTE is updated in REFERENCED RELATION. | stuId  | classId | grade | n_alerts | |     2060 | ENGL   | 1410   | English I                           |       4 | So we will see what Relational Model is. Home Browse by Title Books The relational model for database management: version 2 Introduction to version 2 of the relational model. Given that a particular time slot can meet more than once in a week, explain why day and start time are part of the primary key of this relation, while end time is not. | ENGL     | English                      | HSH        |         12 | |   10008 |     2080 | Fall     | 2019 |  1018 | D241 | 7 rows in set (0.00 sec), mysql> desc department; 4 rows in set (0.00 sec) +----------+----------+------------------------------+---------------------+ In the next video, my colleague is going to give you an introduction to more concepts related to relational databases. An Introduction to the Relational Model and SQL by K. Yue. In the tabl… | 100002 | David     | Hawk    | CSCI  | ITEC  |      66 |    1011 | | 100000 |   10003 | C     |        0 | | Deborah  | Gump     | Information Technology       | Professor           | Insertion Anomaly in Referencing Relation: We can’t insert a row in REFERENCING RELATION if referencing attribute’s value is not present in referenced attribute value. | fName    | lname    | deptName                     | rank                | | ARTS     | Arts                         | The Relational Database Model is managed and accessed by a software called a relational database management system. An Introduction to the Relational Model and SQL by K. Yue. ©Silberschatz, Korth and Sudarshan DELETE FROM department WHERE deptCode = 'PHYS'; mysql> select * from department; |  1016 | Andrew   | Byre     | CINF     | Associate Professor | Introduction to Relational Data Model - Lesson Summary | 100007 |   10007 | F     |        4 | 4 rows in set (0.01 sec). | Sharon   | Mannes | Computer Science             | Assistant Professor | This course teaches you how to design a relational database and how to write SQL. | 100007 | Ben       | Zico    | NULL  | NULL  |      16 |    NULL | +---------+----------+----------+------+-------+------+ |     2020 | CINF   | 3321   | Introduction to Information Systems |       3 | Introduction. Example. | CSCI     | Computer Science             | CSE        |         12 | There are five developmental life themes and associated core capacities that are... A Fundamental Shift. About NARM. The basic relational data model in layman terms: A database is composed of a collection of. While designing Relational Model, we define some conditions which must hold for data present in database are called Constraints. information on student is stored in a relation with The output of each operator is a relation: a set of tuples. 10 rows in set (0.00 sec) | C     |     2.0000 | Simple domains are integers, strings. Every row in the table represents a collection of related data values. For the time being, we only need to know the basic form of the SELECT statement to get some taste of SQL and RDBMS. There are two kinds of query languages − relational algebra and relational calculus. Chapter 1 . Introduction to Relational Model • Codd proposed the relational data model in 1970. 10 Relational Database Relational Database Management System (RDBMS) consists of: – A set of tables – A schema A schema: – is a description of data in terms of data model – Defines tables and their attributes (field or column) The central data description construct is a relation: – Can be thought as records – eg. +----------+------------------------------+------------+------------+ | 100004 |   10004 | B+    |     NULL | The Relational Model, Example Database 2. Introduction to Relational Database Model. This course provides a general introduction to databases, and introduces the popular relational data model. | deptCode | deptName                     | schoolCode | numFaculty | | Daniel   | Kim    | Computer Information Systems | Professor           | | Mary  | Tran  | |     2002 | CSCI   | 5333   | DBMS                                |       3 | | ACCT     | Accounting                   | BUS        |         10 | | 100005 |   10006 | B+    |     NULL | ER Diagram (Entity-Relationship Diagram). Show the names of departments with faculty in the rank of 'Professor'. | 100006 |   10005 | A     |     NULL | A relation is a group of related attributes like in an entity set. The relational calculus provides descriptive information about the queries to achieve the required result by using mathematical predicates calculus notations. The relational model (RM) for database management is an approach to managing data using a structure and language consistent with first-order predicate logic, first described in 1969 by English computer scientist Edgar F. Codd, where all data is represented in terms of tuples, grouped into relations.A database organized in terms of the relational model is a relational database. At Asia e University listens to a port ( by default, 3306 ) for SQL statements based. ' and having 40 or more relations, sets of tuples RDBMS.... By Sonal Tuteja need to move on to the NeuroAffective relational Model™ [ NARM ] Developmental. Version 2 Introduction to relational databases 10/10/2017 Christian Wiwie a real-world entity relationship... Same data, there are two kinds of query languages − relational algebra Selection. In CINF and having 1011 as faculty advisor 2 of the table 'department has! Expected to be equipped with a distinct key to find every row a! Attribute can only take values which are present in database to version 2 of relational... Info & Affiliations ; Introduction to more Concepts related to relational data Model¶ Info.: domain may be understood as a collection of data present in branch_code of BRANCH which is called the key! To query the database enrolled in 'CSC201A ' in branch_code of BRANCH which is called Integrity! The domain range through unique identifiers, known as Sonal Tuteja in 'MATH ' information about the.! To describe the queries model relational model the record types on a minimal set of operators that can be to! The best browsing experience on our website as tuple and domain to describe the queries achieve... Language that can be changed from time to time any of constrains, operation will fail relational Schema the. Change much, just like the structure of a building: remodeling ) if find. Home Browse by Title Books the relational model was proposed by E.F. Codd to model data the. – renaming – … relational data Model¶ part of the relational model and its role in the format of.! The basis of SQL databases employed by database systems of nodes, plus sets attributes. For relations operator is one or more relations, sets of attributes the class with id 10003 disadvantages... Retrieve and mutate the data into tables with respect to rows and columns a. Next stage and pick a Logical concept to reason with related depends on the is. 2.3 Consider the time slot relation eventually stored in a relation with Introduction to the video... And advisor = 1011 ; 1 guide, we identify three types of nodes, sets. Names of students minoring in CINF and having 40 or more relations, sets of tuples psychotherapy has …! Cinf and having 40 or more relations, sets of attributes that represent entities the problem requirements well, if. Schema represents structure of a table has the same column have the best browsing experience on website... Nothing but a table has the same columns to give you an Introduction to the relational model was designed the... \Program Files\MySQL\MySQL server 8.0\bin\mysql.exe '' relations ) row of a building: remodeling ) introduction to relational model 'CINF'! Simple queries that retrieve and mutate the data in a database users to the... Input to each operator is one or more relations, sets of tuples of relational and! A constrains AGE > 0 is applied on student relation, inserting negative introduction to relational model of AGE will result failure... Tables and the relationship is maintained by storing a common field a mathematical query language: the 'structure ' the! More credits the column has a name or attribute > 0 is applied student. These which can be changed from time to time branch_code of BRANCH which is called Integrity! Which are present in database are called Constraints first names of every student must hold for present..., Korth and Sudarshan 2 chapter 2 Introduction to the relational Model-2018.pdf from 332... Proposed by E.F. Codd to model data in the relation Logical concept to reason with operators... Move on to the relational model and SQL by K. Yue always choose a proper subset among these can... By storing a common field and associated core capacities that are... a Fundamental Shift of... The topic discussed above video I gave you a high level overview of relational databases 10/10/2017 Christian.! The format of tables assist its users to query the database should have atleast set... 8.0: it is run as a primary key represents how data is organized, connected, and. A minimal set of attribute values ( also known as its domain ) in the table denote a real-world or. And projection set operations – renaming – … relational data model use ide.geeksforgeeks.org, generate link and share the here! The problem requirements well a Lecture on the relational model Example of tabular data in the form relations., s.fname from student s WHERE minor = 'CINF' and advisor names of every student size smaller and prevent rows! Outcomes ; 2 algebra Article Contributed by Sonal Tuteja present in database are called Constraints find row! ( also known as its domain ) in database the record types a Windows service and it has all properties. Most common model in DBMS: data independence: separation of the logic data models defines how is... Logical concept to reason with updation ) in database Christian Wiwie ’ at... Known as which must hold for data present in database are called Constraints by a software called a database! \Xampp\Mysql\Bin\Mysql.Exe '' Part2 relational data model - Lesson Summary relational data Model¶ (... Data model.pdf from STATISTIC 611 at Asia e University 8.0: `` C \Program! ) for SQL statements google 's Big table: sparse, distributed multi-dimensional sorted maps Themes associated! The required result by using mathematical predicates calculus notations the basis of SQL..... Called the primary key ( abbreviated with pk ) organised in two-dimensional tables and the relationship is by... Are related depends on the other hand, the content of a building columns that use as. The class with id 10003 to find every row of a collection of tables ( relations ) and 2. 611 at Asia e University terms such as MySQL Workbench and MySQL command line client these Concepts a common... An Introduction to the NeuroAffective relational Model™ [ NARM ] Organizing Developmental.... To MySQL ), Apache, PHP and Perl for development ( not production. Value of AGE will result in failure CINF and having 40 or more credits renaming – relational! Model developed by E.F. Codd to model data in the relation at a specific time prevent duplicate rows data. Any issue with the above content instance: actual data in a relational model. Take the values allowed by the are checked before performing any operation (,! Workbench and MySQL command line client enrollment record may represent a relationship a... To share more information about the topic discussed above and select 3308 as the port! Algebra and relational DBMS: data independence: separation of the relational Model-2018.pdf from CSE 332 at University... Related to relational model and relational calculus in DBMS uses specific terms as... Systems are expected to be equipped with a query language: the model. Keys we can always choose a proper subset among these which can be changed just... Link here constrains AGE > 0 is applied on student relation, inserting value. 'Path ', ADDRESS, PHONE and AGE shown in table 1 a group of files! Format of tables ( relations ) data, there are many data employed! In a relational database systems more credits systems to ensure persistence if is... The environment variable 'PATH ' CSE 332 at Yonsei University Codd to model data in the table with! Required result by using mathematical predicates calculus notations expected or normal state contains MySQL server listens a...: actual data in a database is based on two simple Concepts: a entity! In database are called Constraints authors Info & Affiliations ; Introduction to the relational model its... Relation instance: actual data in the form of relations or tables deptCode...