Welcome to CSE3180 ‘Principles of Database Systems’ First Semester 2005 This NOT This CSE3180 Semester 1,2005. Lect 1 / 1 Introduction to CSE3180 This unit covers many aspects associated with database, and in this series of lectures, those related to Relational Data Base (but not exclusively) I’m : Rod Simpson My Office is : Room C 4.46 My Phone contact number is : (03)990 32352 My email is rod.simpson@csse.monash.edu.au My contact times are very limited as I’m running another unit concurrently. CSE3180 Semester 1,2005. Lect 1 / 2 Which stands for School of Computer Science and Software Engineering Faculty of Information Technology CSE3180 Semester 1,2005. Lect 1 / 3 The Time Table Laboratory Sessions will take place from 9.30am to midday • • • • Monday, November 22nd to Wednesday November 24th Monday, November 29th to Wednesday December 1st Monday, December 6th to Wednesday December 8th The laboratories are • The examination will be held on Friday 10th December from 1.30pm to 3.45pm CSE3180 Semester 1,2005. Lect 1 / 4 Assessment A 2 hour written examination December) Contribution 50% Friday 10th A 2 part assignment Contribution 50% - 5 short questions on database related terms and application (15%) - The development of a database and queries relative to Monash University Laboratory facilities (35%) CSE3180 Semester 1,2005. Lect 1 / 5 The Time Table Lectures will take place from 1.00pm to 4.00pm • Monday, November 22nd to Wednesday November 24th • Monday, December 29th to Wednesday December 1st • Monday, December 6th to Wednesday December 8th • The examination will be held on Friday 10th December from 1.30pm to 3.45pm CSE3180 Semester 1,2005. Lect 1 / 6 No relationship CSE3180 Semester 1,2005. Lect 1 / 7 PRINCIPLES OF DATABASE CSE3180 Semester 1,2005. Lect 1 / 8 Introduction Part 2 Special and Important Notice Today is the LAST DAY for withdrawing from this unit without penalty CSE3180 Semester 1,2005. Lect 1 / 9 Introduction Part 3 The notes for this unit can be found on the Monash Web Page at this address: http://www.csse.monash.edu.au/courseware/cse3180s The overheads are in PowerPoint (Office 97) format and can be viewed on the File Server software. There are other notes and papers in Microsoft Word CSE3180 Semester 1,2005. Lect 1 / 10 Lecture Objectives • This lecture will cover: – some thoughts on data storage and retrieval constraints – what is the form of the ‘data’ – some definitions of ‘data’, ‘information’, ‘audit trail’ – what is a data base - who would want one CSE3180 Semester 1,2005. Lect 1 / 11 Lecture Objectives – some of the functions of the database management software – different models (commercial) – the relational model – advantages and disadvantages of database – – some practical aspects of your assignment CSE3180 Semester 1,2005. Lect 1 / 12 Introduction Part 4 Course Outline As you will see from the notes, the recommended text is Hoffer, Prescott and McFadden’s ‘Database Management’. Edition 7. The examples and the exercises at the end of most chapters are well worth a read, and they form the basis of the examination questions (the exam is scheduled for Friday 12th December) Another recommended text is Thomas Connolly and Caroline Beggs ‘DataBase Systems’ 3rd Edition. CSE3180 Semester 1,2005. Lect 1 / 13 Introduction Part 4 There is one assignment, with 2 Parts, and it is expected that you will work in groups - your tutors should have arranged that this morning. The assignment support software is either Oracle or MS Access. If you wish to use some other DBMS, (such as SQLServer or MySQL) you will need to come to some amicable arrangement with your tutor CSE3180 Semester 1,2005. Lect 1 / 14 Introduction Features of database such as – – – – – – Recovery Security Consistency Concurrency Database Management architecture Background processes will be based on Oracle’s version 8i. You will be using a 9i client in the labs. CSE3180 Semester 1,2005. Lect 1 / 15 Database This morning’s exercise would have alerted you to the need to understand what requirements are made of data analyses, who needs these analyses, when and in what form. In all this there is an expectation that the results of ‘queries’, which is the same as saying data supported by the database, is accurate, timely and complete. In these lectures, you will see how these requirements can be built into a database - as you will do with your database model. And that is what it is - a model which accurately reflects data as it occurs and is processed in the ‘real world’. CSE3180 Semester 1,2005. Lect 1 / 16 Some Thoughts on Data Storage • A major benefit of Computing is the ability to STORE and RETRIEVE large amounts of data • However, there are a number of processes and other considerations which need to be worked together to maximise this benefit • Some very early items are – What data ? – What are its sources ? – What are the volumes /frequency ? – How long is to be stored and Why this period ? – In what FORM is it to be stored ? CSE3180 Semester 1,2005. Lect 1 / 17 Some Thoughts on Data Retrieval • Who is going to ‘access’ (retrieve or query) this data ? • How often ? • From where ? • Why is data to be accessed - for what purpose ? CSE3180 Semester 1,2005. Lect 1 / 18 Some Thoughts on Data Retrieval • How is it to be accessed ? Voice inquiry, remote, by formal request, normal processing schedule, randomly, whenever the ‘need’ arises ? • Is the data to be freely available ? – Are there some limitations on access ? – How are these access limitations managed ? • What value is inherent in the data ? CSE3180 Semester 1,2005. Lect 1 / 19 Some General Thoughts • What time base or volume spread is to be represented by the data ? • What levels of accuracy are to be expected ? • Is data to be available 7 days a week, 24 hours/day ? (24x7) • What response time is expected ? Minimum ? / Tolerable ? And just what does that mean in real value terms ? • How is new or altered data to be directed to existing data ? CSE3180 Semester 1,2005. Lect 1 / 20 Some General Thoughts • How is input access to be controlled ? • When and why is data deleted - who authorises such deletions ? • What does the ‘data’ consist of - characters, objects, audio visual, TV, audio, animation ? • What is the optimum method of storage (organisation) ? CSE3180 Semester 1,2005. Lect 1 / 21 Some Definitions A General Definition: DATA - raw (unprocessed or partly processed) facts which represent the state of entities (things) which have occurred INFORMATION - data which has been processed into a form USEFUL TO THE USER /STAKEHOLDER What is Information to one user may be Data to another user. CSE3180 Semester 1,2005. Lect 1 / 22 Possible influence of ABC Channel 2 ? CSE3180 Semester 1,2005. Lect 1 / 23 Audit Trail General Definition: ‘The presence of data processing media and procedures which allow any and / or all transaction(s) to be traced through ALL STAGES of processing’ This infers that the following devices / techniques are in place: 1. A logging device which ‘traps’ all transactions 2. Some way of tagging each transaction so that it can be identified 3. Some way of retrieving the required transaction(s) 4. Some way of archiving - what is the required period ? 5. Control procedures and processes to ensure integrity CSE3180 Semester 1,2005. Lect 1 / 24 Database A Database is a shared collection of Inter-Related data designed to meet the needs of multiple types of users and applications. This implies that multiple user VIEWS can be defined Data stored is independent of the programs which use it Data is structured to provide a basis for future applications DATABASE = Stored Collection of Related Data May be physically distributed CSE3180 Semester 1,2005. Lect 1 / 25 Database Management Software A DBMS is SOFTWARE which provides access to the database in an integrated and controlled manner A DBMS must contain : 1. Data Definition and Structure capabilities 2. Data Manipulation capabilities CSE3180 Semester 1,2005. Lect 1 / 26 Data Definition and Manipulation Data Definition Language (DDL) used to describe data at the database level Schema level - complete database description Sub-Schema level - user views (restricted) Data Manipulation Language (DML) Provides for these Create capabilities Update Delete Modify Report Insert Retrieve (extract) Drop Calculation CSE3180 Semester 1,2005. Lect 1 / 27 CSE3180 Semester 1,2005. Lect 1 / 28 The Many Faces of Database Databases can be: 1. Transaction Intensive 2. Decision Support 3. Mixed-Load 4. Small databases 5. Very Large Database (VLDB) 6. Non Traditional 7. Mobile ATM’s Checkouts Browsing for trends Combination of both Few thousand records Many millions or trillions of records (Banks) - Weather bureau, flight plans Computer Aided Design data - Able to ‘move around’ - CSE3180 Semester 1,2005. Lect 1 / 29 DBMS Requirements Querying Capabilities Data Displays (Presentation) Data entry Data Validation Data Deletion Committing Procedures (of changes) AND Data Integrity, Security, Consistency and Concurrency Capabilities CSE3180 Semester 1,2005. Lect 1 / 30 The Many Faces of Database • They can be: Data Warehouses Data Marts (or martlets) • How is a database size measured ? There are a number of ‘measurements’ Raw data size Total database size Total usable disk space size (which includes media protection such as mirroring) CSE3180 Semester 1,2005. Lect 1 / 31 The Many Faces of Database Hardware Database Raw Data Total Disk HP9000 Oracle 100GB 643GB Digital 8400 Oracle 100GB 361GB IBM SP2 DB2/6000 100GB 377GB NCR5100 Teradata 100GB 880GB NCR5100 Teradata 1,000GB 3,280GB CSE3180 Semester 1,2005. Lect 1 / 32 Important Database Features • • • • • Data Integrity Data Independence Referential Integrity - Relational Database Model Concurrency Control - Multiple Users Consistency - multi users - distributed database - replicated database - partitioned database - mobile database • Recovery from failure (Transaction and Media) • Security CSE3180 Semester 1,2005. Lect 1 / 33 Data Base Models - Hierarchical owner / parent owner child / parent member child child / parent CSE3180 Semester 1,2005. Lect 1 / 34 Data Base Models - Network set of data owner member owner member set of data Note: Only linked sets can be accessed CSE3180 Semester 1,2005. Lect 1 / 35 Data Base Models - Network set of data owner member set of data Note: Only linked sets can be accessed CSE3180 Semester 1,2005. Lect 1 / 36 Data Base Models - Relational table A table B table C table D table E Any table(s) can be joined to any other table(s), provided there is a means of effecting the join Primary key / Foreign key concept. Data redundancy No fixed linkages CSE3180 Semester 1,2005. Lect 1 / 37 A quick introduction to the developer of the Relational Data Base The late Dr. E. Codd CSE3180 Semester 1,2005. Lect 1 / 38 A Primary Key - What’s that ? • Hoffer, Prescott and McFadden define a Primary Key as : An attribute (or combination of attributes) which uniquely identifies each row in a relation. (table) • Richard T. Watson has this to say: The primary key definition block specifies a set of column values comprising the primary key. Once a Primary Key is defined, the system enforces its uniqueness by checking that the Primary Key of any new row does not already exist in the table. CSE3180 Semester 1,2005. Lect 1 / 39 And - A Foreign Key ?? • Hoffer, Prescott and McFadden’s definition: An attribute (or attributes) in a relation (table) of a database which serves as the Primary Key of another relation (table) in the same database. • Richard T. Watson says: An attribute (or attributes) that is a Primary Key in the same table, or another table. It is the method of recording relations in a relational database. And, both the Primary and Foreign Key(s) should be drawn from the same Domain. CSE3180 Semester 1,2005. Lect 1 / 40 2 relations EMPNUM NAME Date of Birth DEPTNUM 3 JONES 16-05-1956 605 Referencing 7 SMITH 23-09-1965 432 Table 11 ADAMS 11-08-1972 201 15 NGUYEN 23-10-1964 314 18 PHAN 16-11-1976 201 23 SMITH 19-09-1974 314 Relation (Table) Name : EMP Relation Schema: EMP(empnum,name,date of birth,deptnum) DEPTNUM 201 314 432 605 DEPTNAME Production Finance Information Systems Administration Relation (Table) Name : DEPT Relation Schema: DEPT(deptnum, deptname) Referenced Table CSE3180 Semester 1,2005. Lect 1 / 41 What are these ? EMP DEPT They are the Entities An Employee MUST be associated with one Department Must a Department have AT LEAST one Employee ? Or can there be More Than 1 Employee ? Can there be a Department with NO employees ? Employee Details are : Employee Number, Employee Name, Date of Birth and the Department Code the Employee works in. Department Details are Department Number and Department Name CSE3180 Semester 1,2005. Lect 1 / 42 Relational Database Data is represented in ROW and COLUMN form (matrix) (tuple) (attribute) Collections of related data ---> TABLES (relations) 1 or more tables ----> DATA BASE ATTRIBUTES are generally static ROWS are DYNAMIC and Time-Varying The number of Attributes = DEGREE of a table The number of Rows = CARDINALITY of a table CSE3180 Semester 1,2005. Lect 1 / 43 Some RDB Considerations • • • • • • • Data is held in tables No order of data in tables - row or attribute Concept of Foreign Key - Primary Key relationship Data Typing (number, character ..) - including nulls Query Access - insert, update, delete, retrieval Indexing on candidate (and Primary) keys Integrity Constraints Attribute value ranges Referential Integrity (Foreign Key - Primary Key) Entity Integrity User Defined Integrity • ‘Sets of Data’ retention constraints CSE3180 Semester 1,2005. Lect 1 / 44 Some RDB Considerations • Domain constraints • User defined ‘Rules’ e.g. quantities and values must not be negative; pricing rate must not be zero • Recovery procedures • No explicit linkages between tables • Linking or embedding database operations in a procedural language (Cobol, C ..) • Databases may be distributed across similar or different DBMS’s • Security features CSE3180 Semester 1,2005. Lect 1 / 45 Database Components 1. Back End Engine Used for Disk Input/Output processes (Read/Write/Find) 2. Front End Processor Data manipulation String/Arithmetic/Statistical operations 3. DBMS Interface Data Definition Language (DDL) Data Manipulation Language (DML) 4.Programmer Interface Applications Environment (4GL’s, Embedded capability) CSE3180 Semester 1,2005. Lect 1 / 46 Data Description Language Used to describe data at the Database level Structure: Attributes Schema : Complete description of the database using DDL SubSchema : Describes data in the database as it is ‘known’ to individual programs(processes) or users The segment of logical data record(s) required is commonly known as a VIEW CSE3180 Semester 1,2005. Lect 1 / 47 Data Manipulation Language Language (commands and syntax) used to cause transfers of data from the Database and the Operating Environment and vice versa Variety of Languages - Cobol, C, Java, and SQL as in Access, DB2, dBASEV, Informix, Oracle, VisualDataBase, SQLServer, MySQL Windows versions provide Icons and Menu options which are translated by the DBMS software to Database manipulation commands Typical functions: get, put, replace, seek, update,delete, insert, drop, find, modify CSE3180 Semester 1,2005. Lect 1 / 48 A Typical Database Model Users - keyboard direct User s Menu Options Programs written in Cobol, C, C++, Pascal Java etc. P r o g r a m I n t e r f a c e D B M S Database Database Query Access Language CSE3180 Semester 1,2005. Lect 1 / 49 Advantages of Database • Reduced Data Redundancy • Data Integrity • Data Independence • Data Security • Data Consistency • Easier use of Data via DBMS Tools (Query languages, 4GL's) CSE3180 Semester 1,2005. Lect 1 / 50 Disadvantages of Database • Complexity • Expense • Vulnerability • Size of - disk storage, processor memory • Training Costs • Compatibility • Technology Lock In CSE3180 Semester 1,2005. Lect 1 / 51 More on DBMS Capabilities Required: – the DBMS must provide a natural interface of user data – the interface must be independent of any physical storage structures – different users with different views must be able to access the same database – database changes must be possible without affecting programs which do not use the changes (Physical and Logical Independence) CSE3180 Semester 1,2005. Lect 1 / 52 More on DBMS Other Requirements : Provision of Operational Facilities to ensure: – multi user access control – remote terminal access – restrictions on user access – recovery from system faults – database distribution CSE3180 Semester 1,2005. Lect 1 / 53 Overview of DataBase Data Creation Subject to DataBase Reliability, Content, Completeness Good Data Input to Database Tables SCM BPM CRM ….. : Audit Time Relevance Advanced Business Rules New DBMS New Applications Altered Business Rules Associated with other Business Applications Users People, Other Systems Web based Access CSE3180 Semester 1,2005. Lect 1 / 54 Overview of DataBase Legacy Data from Legacy Systems Current DataBases DataWarehousing Processes Data Mining Business Based Performance Analyses CSE3180 Semester 1,2005. Lect 1 / 55 Your Assignment • Intended to bring together many of the aspects required in DATABASE DESIGN • It is NOT a complete systems design • There is no transaction processing required • The database MUST contain accurate existing data • It must exhibit constraints and other forms of data integrity CSE3180 Semester 1,2005. Lect 1 / 56 CSE3180 Semester 1,2005. Lect 1 / 57 The Assignment Part 1 consists of 5 questions. The intention is to give you familiarity of some of the database terms and environment Part 2 is directed at your developing a database of the Laboratory Devices of Monash University. It probably sounds relatively easy, but don’t be misled. You will need to develop ‘Business Rules’ and these will lead to ‘constraints’ which will effectively be part of the database contents. CSE3180 Semester 1,2005. Lect 1 / 58 The Assignment And you will need to curb your energies in designing the database and its outputs (which should be your first consideration). You have only 3 weeks to plan, design, construct and have your database operational. CSE3180 Semester 1,2005. Lect 1 / 59 Your Assignment • The 2 Parts are designed to give you some understanding of the design requirements of a database - and this means of course, understanding the specific details which the database must address • In Part 2 of the assignment (the model), YOU are the user – You set the ground rules, also known as Business Rules – You need to document these Rules – Don’t make the project too onerous i.e. make the design simple. – That way you will complete both Part 1 and Part 2 in the short period we have CSE3180 Semester 1,2005. Lect 1 / 60 Your Assignment • Part 1 - Analysis and Solution Due Tuesday 30th November (Tuesday week ) • Part 2 - The Details of the University’s Laboratory Inventory Due 8th December - final tutorial session CSE3180 Semester 1,2005. Lect 1 / 61 Your Assignment • One of the group members will need to be the Co-ordinator - do this co-operatively. • Also, some person in the group will need to address the question of documentation !!! • Use of Microsoft Word would be an advantage. CSE3180 Semester 1,2005. Lect 1 / 62 Your Assignment • Part 1 - : – This sets the tempo for the assignment – Make sure you understand the MAJOR aspects • By Wednesday, 24th November you should have some workable ideas about the rest of the assignment - and you should have done some reading or consulting with your tutor regarding the 5 questions CSE3180 Semester 1,2005. Lect 1 / 63 Part 1 For Part 1, there is no code required. The questions are there to provide you with a kick-start mechanism to come to grips with database and its world For Part 2, you will need 1.To understand the nature of the problem 2. Develop scenarios - successful and unsuccessful 3. Verify the scenarios 4. Modify - if or when necessary 5. Develop the ‘Business Rules’ - what combinations can exist / cannot exist - how to control sequences - what checks must be embedded to ensure accuracy CSE3180 Semester 1,2005. Lect 1 / 64 Your Assignment One member will need to act as the Reviewer for – Completeness of both Part 1 and Part 2 – Validity of the Comments made – Validity of the Entity Relationships – Normalisation / Primary key(s) / Foreign key(s) CSE3180 Semester 1,2005. Lect 1 / 65 Your Assignment - Part 2 For Part 2 you will need to develop : – Data structures – Constraints – Test strategy – Test data – Testing results – Operational model CSE3180 Semester 1,2005. Lect 1 / 66 Your Assignment - Part 2 • Make rough outlines of the model of your database Entities plus their relationships (connectivities) • Make rough outlines of any changes to the the Data Structures - these expand and show the attributes of the Entities • Make notes of Rules, and the Constraints, you consider will help the Rules to control data in your database for both existing and future users CSE3180 Semester 1,2005. Lect 1 / 67 Your Assignment • Review the E-R diagram critically - it’s best if one person of the group becomes the ‘Quality Control’. • Each member of the group MUST know what the assignment is about and how it is is being developed. • Prepare the ‘final’ technical paper for Part 1 by Wednesday 1st December • Complete the database, and produce the analyses, by Wednesday 8th December CSE3180 Semester 1,2005. Lect 1 / 68 Your Assignment • You will (probably) be using MS-Access to develop the physical database. Or, you could use Oracle. Or SQLServer (but check with your Tutor) • Become familiar with the Table Design feature – Include Primary Keys, Required Fields, Value Ranges or Exclusions – ‘Numbers’ are ?? – Integers (no decimals) – Numerics with decimals – Text references only • Use data types to constrain data • Use the ‘required’ property in Access or the ‘not null’ type in Oracle CSE3180 Semester 1,2005. Lect 1 / 69 Your Assignment • There should be no need to delve into the Applications Development features of the DBMS. However, if you have some expertise, and time, do so by all means • Make sure you keep a backup of your database CSE3180 Semester 1,2005. Lect 1 / 70 Building Evacuation If the Building Evacuation Alarm System Activates – – – – – – Collect your belongings Move out of the room using the Exits Use the Stairs - NOT the Lifts or Escalators Follow the directions of FLOOR WARDENS - if present Move to the Lawn outside K Block (common) Wait for further instructions (if during the evening use your discretion) – TREAT EVERY EVACUATION ALERT as REAL CSE3180 Semester 1,2005. Lect 1 / 71 The Time Table Laboratory Sessions will take place from 9.30am to midday • Monday, November 22nd to Wednesday November 24th • Monday, November 29th to Wednesday December 1st • Monday, December 6th to Wednesday December 8th • The examination will be held on Friday 10th December from 1.30pm to 3.45pm CSE3180 Semester 1,2005. Lect 1 / 72 That should be enough for today The website : http://www.csse.monash.edu.au/courseware/cse3180s and make sure you reference cse3180s CSE3180 Semester 1,2005. Lect 1 / 73