Tools for Memory: Database Management Systems Susan D. Urban School of Computing and Informatics Department of Computer Science and Engineering Arizona State University 9/22/2018 CPI 101

What is a Database? A database is a structured collection items that is used for the operation of an enterprise Financial data Customer information Sales records Maps and directions Medical records Scientific and biological data Historical data A database supports Correctness and integrity of data Integrated retrieval of related data Concurrent user access to shared data Analysis and decision making Data mining and discovery Security of data 9/22/2018 CPI 101

Types of Data Textual Numeric Image Audio Video Geographic 9/22/2018 CPI 101

What is a Database Management System? A database management system (DBMS) is the software that assists in the creation and maintenance of a database as well as the retrieval of data. A DBMS includes A data model and data definition language (DDL) for specifying a database schema (i.e., the types, structures, and constraints on the data to be stored) A database catalog for storing the database schema. A data manipulation language (DML) for creating and maintaining the database (i.e., inserting, modifying, and deleting data) A query language for retrieving data. A transaction processing system for running application programs Other features to ensure security and integrity of the data 9/22/2018 CPI 101

Implementation Schema DBMS Architectures User View 1 User View 2 User View N Conceptual Schema Data Abstraction Logical Data Independence Implementation Schema Physical Data Independence DBMS 9/22/2018 CPI 101

Different Types of Database Systems Legacy Systems (originated in the 1960’s) Hierarchical Network Relational Database Systems Models data in the form of tables Accounts for the majority of new database projects A $14 billion industry Object-Oriented Database Systems Models data using object-oriented concepts Object-Relational Database Systems Extends relational database systems with object-oriented features Geographic Database Systems Databases specifically for modeling 3D, geographic data Multimedia Database Systems Databases for modeling data in different forms (audio, video, image) 9/22/2018 CPI 101

Relational Database Products Commercial Oracle 10g IBM DB2 Microsoft Access Microsoft SQL Server Informix Sybase Open Source MySQL Ingres PostgreSQL Berkeley DB Cloudscape/Derby 9/22/2018 CPI 101

Data Models and the Database Design Process A database is initially designed by using a conceptual data model. A conceptual data model is DBMS-independent Provides a more logical way of viewing data A conceptual design can then be mapped to DBMS-dependent models. The DBMS handles the internal implementation details of the representation. 9/22/2018 CPI 101

Relationship Between Data Modeling Concepts Database Models Implementation Models Functional Model Conceptual Data Models Legacy Relational Object-Oriented Binary Entity-Relationship Semantic Network Hierarchical Object-Relational Enhanced Entity- Relationship Model Unified Modeling Language Class Diagrams 9/22/2018 CPI 101

Conceptual Modeling with the Entity-Relationship Model 9/22/2018 CPI 101

The Relational Data Model Develop by Ted Codd at IBM in 1970 Models data in the form of tables. Tables are based on the theoretical concept of mathematical relations set theory first-order predicate logic Uses SQL as a declarative query language for data retrieval Describes what you want to retrieve and not how to retrieve it (the DBMS figures out the “how to” part for you) 9/22/2018 CPI 101

Relational Database Concepts Column/Attribute Table/Relation ID Name Addr Phone Age Row/Tuple 123 Joe Phx 9991 30 124 Sue Phx 8888 29 125 Ann Mesa 7772 25 Each column has a specific domain (integer, string, real, etc.) 9/22/2018 CPI 101

Relational Database Example Course: crsid, cname, inst, length Takes: id, crsid, date Dept: dnum, dname, mgrid Emp: id, name, sal, dnum Names in bold are primary keys. Names in italics are foreign keys used to define relationships between tables. These relationships help to support meaningful queries over the data. 9/22/2018 CPI 101

SQL (Structured Query Language) Find the name of the department that each employee works in. select name, dname from emp, dept where emp.dnum = dept.dnum Find the average salary of employees in each department Select dnum, avg(sal) from emp group by dnum order by dnum 9/22/2018 CPI 101

Data Import and Export Data Import – Getting large amounts of data into the database Data export – Getting large amounts of data out of the database Import and export is often needed to transport data from one database to another XML (Extensible Markup Language) has become a standard for data transport. Most current database systems are XML-enabled, providing a way to import and export data using XML and to query XML data types. 9/22/2018 CPI 101

XML Example <employees> <emp> <id>123</id> <name>Joe</name> <sal>30K</sal> <dnum>D1<dnum> </emp> …. </employees> More about this next week….. 9/22/2018 CPI 101

Distributed and Internet-Scale Database Systems Semistructured Data Structured Data DB XML … Query? DB Querying data from different data sources in an integrated manner is a challenging task for the area of information science! Unstructured Data 9/22/2018 CPI 101