CS317 File and Database Systems

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1 CS317 File and Database Systems Lecture 5 More SQL and Intro to Stored Procedures September 24, 2017 Sam Siewert

2 SQL Theory and Standards Completion of SQL in DBS Chapter 5 [Ref: Connolly-Begg Chapters 7 & 8] Part-1 Sam Siewert 2

3 Mid-term Survey Results Sam Siewert 3

4 Bottom 4 Materials Useful - Primarily for SQL Examples and Example DBs along with General Concepts and Terms [CB Ref Material?] Technical Rigor - One last practice assignment Normalization - Required for Safe/Good DB Design! Learn How to Do Ex #5 and #6 are DB Project of your choice! LO Not Clear (Revisit Quickly) LO Review Q&A on LO Technical Rigor RA and TRC Behind Us after Exam #1 - Necessary for Knowing SQL is Correct vs. Magic Normalization Next Technical Section - Necessary for Referential Integrity Sam Siewert 4

5 Learning Objectives - Revisited! Structured and Unstructured Data: Block Storage Block Storage Devices [Disk Drives, SSD, Persistent Memory] Split between Files and Databases [Integration of Both] DML - Data Manipulation using SQL (ISO Standard) DDL - Data Definition Language, Database Design with SQL Logical Design [Schema] - MySQL Workbench Physical Design [Hosting a DB] Theory of Databases Relational ER Models [Workbench] - Data vs. Information OODBMS (SQL Extensions, C++ Alternatives) - Quickly NoSQL - By Reading Relational Algebra <-> SQL Normalization for Referential Integrity (Avoid Duplication, Consistency, Veracity) DBA - Database Administration and Security Physical Aspects of File and Database Systems Physical Implementation and Scaling [Block Partition, File], Indexing [ISAM, B Tree, B+ Tree, R-Tree], Network Access [Connectors], Web Front Ends Sam Siewert 5

6 MySQL on DDL vs. DML DDL DML Query TCL DBA [DCL] Sam Siewert 6

7 Reading Advice Read SQL Chapter 5 using SQ3R (Scan, Question, Read, Recite, Review) Experiment Using Views and Understand they are Normally Stored Queries Rather than New Tables IGNORE View Materialization Use Simple Multi-Table Queries - Nested or Multi-table Theta, Equi and Natural Join Less Emphasis on other JOIN directives (INNER, OUTER, RIGHT and LEFT) To Compare Joins, See this TUTORIAL Sam Siewert 7

8 For Discussion SQL is An Evolving ISO Standard SQL: What We ve Learned So Far is SQL:1992 Core SQL 2. Latest SQL Standards are SQL:2011 and SQL: Better integration of Procedural Language with SQL PL/SQL, SQL/PSM [E.g. MySQL Stored Procedures, Create Procedure] 4. Extensions for Convenience? Other? 5. Security Issues? 6. OO Support? Two Positions (Object RDBMS, New OODBMS) Assignment #3 SQL Advanced Features and Extensions Beyond Core, More Core SQL, ODBMS - Alternative OODBMS and NoSQL Exploration Import ZAGI, HAFH or DreamHome Schema and Data Goal is to Practice SQL for Proficiency and Schema Improvement Practice with Stored Procedures that work with MySQL Compare RDBMS to OODBMS and NoSQL - Structured, Unstructured Sam Siewert 8

9 Overview of Example DBs DreamHome - v1.0, v1.3,, v2.0 [Ref: CB] DBS - ZAGI, Data DBS - HAFH, Schema & Data Learning Objectives Practice SQL DDL Practice SQL DML Practice Loading DBs, Migrating Data, Improving Schemas Understand Limitations of RDBMS and Alternatives Sam Siewert 9

10 Schema Updates Requires Table Alter, Creation of new Tables, Migration of Data Possible Good Use of Nested Query in Insert - Replicated Data to Migrate, Drop Old Table Sam Siewert 10

11 SQL Data Types (Domains) - DDL Lowest Level of Data integrity, validation, veracity Sam Siewert 11

12 ISO SQL Data Types Pearson Education

13 Views Stored Queries by name - CREATE VIEW MyStaff AS SELECT * FROM Staff WHERE branchno= B003 ; select * from MyStaff; DROP VIEW MyStaff; Sam Siewert 13

14 1. More Practice with SQL Chapter 5 - Continued 1. Stored Procedures SQL/PSM (General ISO Standard :1996 Persistent Stored Modules) PL/SQL (Oracle only) Close to SQL/PSM, MySQL Stored Procedures for PRClab also Similar (Stored Programs and Views, Defining, Using) 2. Trigger Basics (MySQL Ref Manual 19.3) - We will use more in Part-2, but understand concepts (covered in Chapter 6) 3. Study Nested Queries and Multi-table 4. Understand ALTER, but also use CREATE and DROP Sam Siewert 14

15 Notes - Stored Programs PL/SQL from CB Ref. does not work on MySQL on PRClab You will not be held accountable for syntax and semantics, just awareness of Stored Programs and Triggers (covered in more depth in Part-2) Stored Programs in MySQL are useful for project DB work I will Provide Simple MySQL Stored Program Examples Today Sam Siewert 15

16 The SQL Programming Language Impedance mismatch Mixing different programming paradigms SQL is a declarative language High-level language such as C is a procedural language SQL and 3GLs use different models to represent data Impedance is the opposition by a system to the flow of energy from a source. [wikipedia] opposition to blood flow in the circulatory system [webster, 3 rd definition] By mismatch, this implies that some of the power of SQL is limited by the Java or C++ embedding and some of the power of Java or C++ is perhaps limited by SQL (they were not designed to be combined not orthogonal, not at same level) E.g. assigning a variable or object to contain tuples returned from select. [Idea - instead of embedding SQL in say C/C++ or Java, rather build in Procedural Extensions to SQL that can be Stored, Like any Other Data] 16

17 MySQL SQL/PSM The ; is default delimiter, so we need to redefine to enter a stored procedure on the command line Select is like printf in MySQL use mysql; delimiter $$ drop procedure if exists helloworld$$ create procedure helloworld() Begin select hello world ; end$$ delimiter ; Helloworld is in table proc Sam Siewert 17

Stored like any other tuple Any number of procedures using

18 Simple MySQL Stored Procedure Classic C/C++ Hello World is Entered into mysql schema in the proc table (relation) It is Stored like any other tuple Any number of procedures using SQL/PSM can be stored They are Invoked with Call Example Sam Siewert 18

19 Where are SQL Stored Procedures? Don t worry about sql_mode Advantages are: 1. Security - on Server rather than Client 2. Managed like any other Data in DB in the mysql DB, in table proc 3. Less data to marshal back and forth between a Client and the DBMS Server 4. Privileges managed Sam Siewert 19

20 Examine mysql DB and tables SQL Procedures are Stored at Tuples in proc Sam Siewert 20

21 MySQL PSM Example Note SET REPEAT = for Assignment, but := OK too Does Not Agree with PL/SQL, but Equivalent Capability Sam Siewert 21

22 Triggers - Cover in Chap 6, Part-2 Trigger Defines an action that the database should take when some event occurs in the application Based on Event-Condition-Action (ECA) model Types Row-level Statement-level Event: INSERT, UPDATE or DELETE Timing: BEFORE, AFTER or INSTEAD OF Advantages and disadvantages of triggers 22

23 MySQL Trigger Example INSERT Trigger to Sum Debit/Credit for all Accounts Sam Siewert 23

MySQL Trigger Example UPDATE Trigger to Range Limit Data 0 100 Can

24 MySQL Trigger Example UPDATE Trigger to Range Limit Data Can t use CALL in Trigger Can t begin or end a transaction Sam Siewert 24

25 Triggers Advantages Elimination of redundant code Simplifying modifications Increased security Improved integrity Improved processing power Good fit with client-server architecture 25

26 Triggers Disadvantages Performance overhead Cascading effects Cannot be scheduled Less portable 26

27 Discussion Goal of RDBMS is Minimal Redundant Data Foreign Keys are Ideally the Only Redundant Data Used for Hierarchical Relations Goal of Normalization is to Eliminate Redundancy (Chapter 14) Insertion Anomalies Deletion Anomalies Modification Anomalies Recall E.F. Codd s Concerns with Redundancy So, Not Just Efficiency Issues OOA/OOD and OOP Have Redundancy via Inheritance Refinement of Classes and Instantiation RDBMS minimizes redundancy via PK to FK hierarchy in relations Sam Siewert 27

28 Connolly-Begg Chapter 7 SQL RDBMS Practice (Data Types & Schema Level Commands) Sam Siewert 28

29 DreamHome Schema CB Ref. Page 112, Figure 4.3 CB Ref. Chapter 7, Problem 7.21, 7.22 Create table(s) for schema loaded on Bb with tab delimited data Can be Used to Verify Examples in CB Ref. Chapter 5 & 6 Sam Siewert 29

30 CB Ref - Examples Dream Home v ome-db-v1.0/ CB Ref. has good RA and TRC Examples as well as Dream Home DDL and DML examples Practice on SQL Friday(s) in class - E.g. Dream Home Found also in Dream Home Exercise and Notes from Week 6 - Lecture-Week-6-2 Sam Siewert 30

31 DBS - Jukic et al. Chapter 5 SQL RDBMS Practice (Data Types & Schema Level Commands) Sam Siewert 31

32 DBS Book SQL Examples Part 1 - Basic Core SQL and ZAGI Example DCL is what we call DBA Commands TCL we will cover in Part-2 of the Course Students can DROP tables and views, but not whole databases Single Table SELECT with predicates Ordering and Aggregate Functions Part 2 - Advanced SQL and HAFH Example Nested Queries vs. Multi-Table (Theta-JOIN or Equi-JOIN) Note key-word JOIN not used for these Equi-join is a special case of Theta-join Natural join is special case of Equi-join over common attributes MySQL Manual on JOIN, Join Types Tutorial Views are stored Queries (rather than storing duplicate data) SQL Implementation Differences (MySQL, MS SQL, Oracle Enterprise, SQLite, etc.) Sam Siewert 32

33 HAFH and ZAGI Examples DBS Examples Schema IM and DDL provided Many query examples - DBS Chapter 5 Notes View examples - Stored Queries Schema update commands to alter tables, insert data, etc. Practice with DreamHome (CB Ref.) and with DBS HAFH and ZAGI to Learn Bring Questions to Class! Sam Siewert 33

CS317 File and Database Systems

CS317 File and Database Systems Lecture 3 Relational Model & Languages Part-1 September 7, 2018 Sam Siewert More Embedded Systems Summer - Analog, Digital, Firmware, Software Reasons to Consider Catch