IS 257 - Fall 2002 2002.11.05- SLIDE 1

Data Administration and Database Administration

University of California, Berkeley

School of Information Management and Systems

SIMS 257: Database Management

IS 257 - Fall 2002 2002.11.05- SLIDE 2

Lecture Outline

• Final Project Requirements

• Review– Fourth Generation Languages– Object-Relational Extensions to SQL

• Database Administration

IS 257 - Fall 2002 2002.11.05- SLIDE 3

Final Project Requirements

• See WWW site:– http://sims.berkeley.edu/courses/is257/f02/index.html

• Report on personal/group database including:– Database description and purpose– Data Dictionary– Relationships Diagram– Sample queries and results (Web or Access tools)– Sample forms (Web or Access tools)– Sample reports (Web or Access tools)– Application Screens or pages (Web or Access tools)– In-class report on database

IS 257 - Fall 2002 2002.11.05- SLIDE 4

Fourth Generation Languages

• 1st Generation -- Machine Language

• 2nd Generation -- Assembly Languages

• 3rd Generation -- High-Level Languages

• 4th Generation -- Non-Procedural Languages

• 5th Generation -- ?? Knowledge-based ?? Natural Language ??

• Where do Object-Oriented Languages fit??

IS 257 - Fall 2002 2002.11.05- SLIDE 5

Components of a 4GL

Application Parameters

Testingtools/debugger

InterpreterOptimizingcompiler

RulesSpecification

DataSpecification

ReportSpecification

ScreenSpecification

Proceduralfacility

Feedback

for building routine applications…

IS 257 - Fall 2002 2002.11.05- SLIDE 6

Natural Language

• Advantages of using NL– It encourages untrained users to start– It encourages upper-management use of

computers– It reduces the time taken learning complex

syntax – It lessens the frustration, bewilderment and

anger caused by BAD COMMAND responses– It is likely to extend greatly the usage of

computers James Martin, Fourth Generation Languages, 1985

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Natural Language

• It lacks precision• It is not good for

expressing precise and complex logic

• It is not good for expressing neat structures

• It encourages semantic overshoot

• It should be combined with other dialogue contructs that aid in the representation of precise logic and structures

James Martin, Fourth Generation Languages, 1985

Disadvantages of using NL Appropriate response to the disadvantage

IS 257 - Fall 2002 2002.11.05- SLIDE 8

Natural Language

• It takes substantial time to key in sentences

• Ambiguities are possible

• Substantial processing is needed

• Sentences and words can be abbreviated

• Speech input as well as typed input will be used

• The computer should detect and resolve ambiguities

• The processing should be on PC workstations. Processing is dropping rapidly in cost.

James Martin, Fourth Generation Languages, 1985

Disadvantages of using NL Appropriate response to the disadvantage

IS 257 - Fall 2002 2002.11.05- SLIDE 9

Assumptions and Issues

• Why 4GLs?– Are they still appropriate?– Are they still useful?

• Is Cold Fusion a 4GL?

• What about PHP?

• Who needs them?

IS 257 - Fall 2002 2002.11.05- SLIDE 10

Object Relational Data Model

• Class, instance, attribute, method, and integrity constraints

• OID per instance• Encapsulation• Multiple inheritance hierarchy of classes• Class references via OID object

references• Set-Valued attributes• Abstract Data Types

IS 257 - Fall 2002 2002.11.05- SLIDE 11

Object-Relational SQL in ORACLE

• CREATE (OR REPLACE) TYPE typename AS OBJECT (attr_name, attr_type, …);

• CREATE TABLE OF typename;

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Example

• CREATE TYPE ANIMAL_TY AS OBJECT (Breed VARCHAR2(25), Name VARCHAR2(25), Birthdate DATE);

• Creates a new type

• CREATE TABLE Animal of Animal_ty;

• Creates “Object Table”

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Constructor Functions

• INSERT INTO Animal values (ANIMAL_TY(‘Mule’, ‘Frances’, TO_DATE(‘01-APR-1997’, ‘DD-MM-YYYY’)));

• Insert a new ANIMAL_TY object into the table

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Selecting from an Object Table

• Just use the columns in the object…

• SELECT Name from Animal;

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More Complex Objects

• CREATE TYPE Address_TY as object (Street VARCHAR2(50), City VARCHAR2(25), State CHAR(2), zip NUMBER);

• CREATE TYPE Person_TY as object (Name VARCHAR2(25), Address ADDRESS_TY);

• CREATE TABLE CUSTOMER (Customer_ID NUMBER, Person PERSON_TY);

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What Does the Table Look like?

• DESCRIBE CUSTOMER;

• NAME TYPE

• -----------------------------------------------------

• CUSTOMER_ID NUMBER

• PERSON NAMED TYPE

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Inserting

• INSERT INTO CUSTOMER VALUES (1, PERSON_TY(‘John Smith’, ADDRESS_TY(‘57 Mt Pleasant St.’, ‘Finn’, ‘NH’, 111111)));

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Selecting from Abstract Datatypes

• SELECT Customer_ID from CUSTOMER;

• SELECT * from CUSTOMER;

CUSTOMER_ID PERSON(NAME, ADDRESS(STREET, CITY, STATE ZIP))---------------------------------------------------------------------------------------------------1 PERSON_TY(‘JOHN SMITH’, ADDRESS_TY(‘57...

IS 257 - Fall 2002 2002.11.05- SLIDE 19

Selecting from Abstract Datatypes

• SELECT Customer_id, person.name from Customer;

• SELECT Customer_id, person.address.street from Customer;

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Updating

• UPDATE Customer SET person.address.city = ‘HART’ where person.address.city = ‘Briant’;

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Functions

• CREATE [OR REPLACE] FUNCTION funcname (argname [IN | OUT | IN OUT] datatype …) RETURN datatype (IS | AS) {block | external body}

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TRIGGERS

• Create TRIGGER UPDATE_LODGING INSTEAD OF UPDATE on WORKER_LODGING for each row BEGIN

• if :old.name <> :new.name then update worker set name = :new.name where name = :old.name;

• end if;

• if :old.lodging <> … etc...

IS 257 - Fall 2002 2002.11.05- SLIDE 23

Today

• Traditional and Current Data Administration

• Traditional and Current Database Administration

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Changes in Traditional Roles

• This is being driven by rapid changes in– Technology– Platforms (e.g., Micro vs. Mainframe vs.

Server)– Organizational Structure

• We will focus on the core functions and tasks of these roles (traditional or current)

IS 257 - Fall 2002 2002.11.05- SLIDE 25

Terms and Concepts (trad)

• Data Administration– Responsibility for the overall management

of data resources within an organization

• Database Administration– Responsibility for physical database design

and technical issues in database management

• These roles are often combined or overlapping in some organizations

IS 257 - Fall 2002 2002.11.05- SLIDE 26

Terms and Concepts (trad)

• DA– Data adminstrator - person responsible for the

Data Administration function in an organization

– Sometimes may be the CIO -- Chief Information Officer

• DBA– Database Administrator - person responsible

for the Database Administration Function

IS 257 - Fall 2002 2002.11.05- SLIDE 27

Database System Life Cycle

Operation &Maintenance

DatabaseImplementation

DatabaseDesign

Growth &Change

DatabaseAnalysis

DatabasePlanning

Note: this is a different version of thislife cycle than discussed previously

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Database Planning

• Development of a strategic plan for database development that supports the overall organization’s business plan

• DA supports top management in development of this plan

• The result of this stage is an enterprise data model

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Database Planning: DA & DBA functions

• Develop corporate database strategy (DA)

• Develop enterprise model (DA)

• Develop cost/benefit models (DA)

• Design database environment (DA)

• Develop data administration plan (DA)

IS 257 - Fall 2002 2002.11.05- SLIDE 30

Database Analysis

• This is the process (discussed previously) of identifying data entities currently used by the organization, precisely defining those entities and their relationships, and documenting the results in a form that can support the follow-on design phase

• Must also identify new data elements or changes to data elements that will be required in the future

• The result of this phase is the Conceptual Data Model -- usually represented as an ER diagram

IS 257 - Fall 2002 2002.11.05- SLIDE 31

Database Analysis: DA & DBA functions

• Define and model data requirements (DA)

• Define and model business rules (DA)

• Define operational requirements (DA)

• Maintain corporate Data Dictionary (DA)

IS 257 - Fall 2002 2002.11.05- SLIDE 32

Database Design

• Purpose of the design phase is the development of the logical database design that will serve the needs of the organization and the physical design implementing the logical design

• In relational systems the outcome is normalized relations, and the data definition for a particular database systems (including indexes, etc.)

IS 257 - Fall 2002 2002.11.05- SLIDE 33

Design 2: Physical Creation

• Development of the Physical Model of the Database– data formats and types– determination of indexes, etc.

• Load a prototype database and test

• Determine and implement security, privacy and access controls

• Determine and implement integrity constraints

IS 257 - Fall 2002 2002.11.05- SLIDE 34

Database Design: DA &DBA functions

• Perform logical database design (DA)

• Design external models (subschemas) (DBA)

• Design internal model (Physical design) (DBA)

• Design integrity controls (DBA)

IS 257 - Fall 2002 2002.11.05- SLIDE 35

Database Implementation

• Database design gives you an empty database

• Load data into the database structure

• Convert existing data sets and applications to use the new database– May need programs, conversion utilities to

convert old data to new formats.

• Outcome is the actual database with its data

IS 257 - Fall 2002 2002.11.05- SLIDE 36

Database Implementation DA & DBA functions

• Specify database access policies (DA & DBA)• Establish Security controls (DBA)• Supervise Database loading (DBA)• Specify test procedures (DBA)• Develop application programming standards

(DBA)• Establish procedures for backup and recovery

(DBA)• Conduct User training (DA & DBA)

IS 257 - Fall 2002 2002.11.05- SLIDE 37

Operation and Maintenance 1: Operations

• Users are responsible for updating the database, DA and DBA are responsible for developing procedures that ensure the integrity and security of the database during the update process.

• Specific responsibility for data collection, editing and verification must be assigned

• Quality assurance must be practiced to protect and audit the database quality.

IS 257 - Fall 2002 2002.11.05- SLIDE 38

Operation and Maintenance 2: Maintenance

• The ongoing process of updating the database to keep it current – adding new records– deleting obsolete records– changing data values in particular records– modifying relation structures (e.g. adding new fields)

• Privacy, security, access control must be in place.

• Recovery and Backup procedures must be established and used

IS 257 - Fall 2002 2002.11.05- SLIDE 39

Operation and Maintenance: DA & DBA functions

• Monitor database performance (DBA)

• Tune and reorganize databases (DBA)

• Enforce standards and procedures (DBA)

• Support users (DA & DBA)

IS 257 - Fall 2002 2002.11.05- SLIDE 40

Growth & Change

• Change is a way of life– Applications, data requirements, reports, etc.

will all change as new needs and requirements are found

– The Database and applications and will need to be modified to meet the needs of changes to the organization and the environment

– Database performance should be monitored to maintain a high level of system performance

IS 257 - Fall 2002 2002.11.05- SLIDE 41

Growth & Change: DA & DBA functions

• Implement change control procedures (DA & DBA)

• Plan for growth and change (DA & DBA)

• Evaluate new technology (DA & DBA)

IS 257 - Fall 2002 2002.11.05- SLIDE 42

Functions in Database Administration

• Planning and Design (we have already looked at theses processes in detail)

• Data Integrity

• Backup and Recovery

• Security Management

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Data Integrity

• Intrarecord integrity (enforcing constraints on contents of fields, etc.)

• Referential Integrity (enforcing the validity of references between records in the database)

• Concurrency control (ensuring the validity of database updates in a shared multiuser environment)

IS 257 - Fall 2002 2002.11.05- SLIDE 44

No Concurrency Control: Lost updates

• Read account balance (balance = $1000)

• Withdraw $200 (balance = $800)

• Write account balance (balance = $800)

• Read account balance (balance = $1000)

• Withdraw $300 (balance = $700)

• Write account balance (balance = $700)

John Marsha

ERROR!

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Concurrency Control: Locking

• Locking levels– Database– Table– Block or page– Record– Field

• Types– Shared (S locks)– Exclusive (X locks)

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Concurrency Control: Updates with X locking

• Lock account balance• Read account balance

(balance = $1000)• Withdraw $200 (balance

= $800)• Write account balance

(balance = $800)• Unlock account balance

• Read account balance (DENIED)

• Lock account balance• Read account balance

(balance = $800)• etc...

John Marsha

IS 257 - Fall 2002 2002.11.05- SLIDE 47

Concurrency Control: Deadlocks

• Place S lock• Read account

balance (balance = $1000)

• Request X lock (denied)

• wait ...

• Place S lock• Read account

balance (balance = $1000)

• Request X lock (denied)

• wait...

John Marsha

Deadlock!

IS 257 - Fall 2002 2002.11.05- SLIDE 48

Concurrency Control

• Avoiding deadlocks by maintaining tables of potential deadlocks and “backing out” one side of a conflicting transaction

IS 257 - Fall 2002 2002.11.05- SLIDE 49

Database Security

• Views or restricted subschemas• Authorization rules to identify users and

the actions they can perform• User-defined procedures (and rule

systems) to define additional constraints or limitations in using the database

• Encryption to encode sensitive data• Authentication schemes to positively

identify a person attempting to gain access to the database

IS 257 - Fall 2002 2002.11.05- SLIDE 50

Views

• A subset of the database presented to some set of users– SQL:

CREATE VIEW viewname AS SELECT field1, field2, field3,…, FROM table1, table2 WHERE <where clause>;

– Note: “queries” in Access function as views

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Authorization Rules

• Most current DBMS permit the DBA to define “access permissions” on a table by table basis (at least) using the GRANT and REVOKE SQL commands

• Some systems permit finer grained authorization (most use GRANT and REVOKE on variant views

IS 257 - Fall 2002 2002.11.05- SLIDE 52

Database Backup and Recovery

• Backup

• Journaling (audit trail)

• Checkpoint facility

• Recovery manager

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Disaster Recovery Planning

Testing andTraining

ProceduresDevelopment

Budget &Implement

PlanMaintenance

RecoveryStrategies

RiskAnalysis

From Toigo “Disaster Recovery Planning”

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Threats to Assets and Functions

• Water

• Fire

• Power Failure

• Mechanical breakdown or software failure

• Accidental or deliberate destruction of hardware or software– By hackers, disgruntled employees, industrial

saboteurs, terrorists, or others

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Threats

• Between 1967 and 1978 fire and water damage accounted for 62% of all data processing disasters in the U.S.

• The water damage was sometimes caused by fighting fires

• More recently improvements in fire suppression (e.g., Halon) for DP centers has meant that water is the primary danger to DP centers

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Kinds of Records

• Class I: VITAL – Essential, irreplaceable or necessary to recovery

• Class II: IMPORTANT– Essential or important, but reproducible with difficulty

or at extra expense

• Class III: USEFUL– Records whose loss would be inconvenient, but which

are replaceable

• Class IV: NONESSENTIAL– Records which upon examination are found to be no

longer necessary

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Offsite Storage of Data

• Early offsite storage facilities were often intended to survive atomic explosions

• PRISM International directory

• Mirror sites (Hot sites)