SLIDE 1IS Fall 2002 Data Administration and Database Administration University of California, Berkeley School of Information Management and Systems SIMS 257: Database Management

SLIDE 2IS Fall 2002 Lecture Outline Final Project Requirements Review –Fourth Generation Languages –Object-Relational Extensions to SQL Database Administration

SLIDE 3IS Fall 2002 Final Project Requirements See WWW site: – 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

SLIDE 4IS Fall 2002 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??

SLIDE 5IS Fall 2002 Components of a 4GL Application Parameters Testing tools/debugger Interpreter Optimizing compiler Rules Specification Data Specification Report Specification Screen Specification Procedural facility Feedback for building routine applications…

SLIDE 6IS Fall 2002 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

SLIDE 7IS Fall 2002 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

SLIDE 8IS Fall 2002 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

SLIDE 9IS Fall 2002 Assumptions and Issues Why 4GLs? –Are they still appropriate? –Are they still useful? Is Cold Fusion a 4GL? What about PHP? Who needs them?

SLIDE 10IS Fall 2002 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

SLIDE 11IS Fall 2002 Object-Relational SQL in ORACLE CREATE (OR REPLACE) TYPE typename AS OBJECT (attr_name, attr_type, …); CREATE TABLE OF typename;

SLIDE 12IS Fall 2002 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”

SLIDE 13IS Fall 2002 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

SLIDE 14IS Fall 2002 Selecting from an Object Table Just use the columns in the object… SELECT Name from Animal;

SLIDE 15IS Fall 2002 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);

SLIDE 16IS Fall 2002 What Does the Table Look like? DESCRIBE CUSTOMER; NAME TYPE CUSTOMER_ID NUMBER PERSON NAMED TYPE

SLIDE 17IS Fall 2002 Inserting INSERT INTO CUSTOMER VALUES (1, PERSON_TY(‘John Smith’, ADDRESS_TY(‘57 Mt Pleasant St.’, ‘Finn’, ‘NH’, )));

SLIDE 18IS Fall 2002 Selecting from Abstract Datatypes SELECT Customer_ID from CUSTOMER; SELECT * from CUSTOMER; CUSTOMER_ID PERSON(NAME, ADDRESS(STREET, CITY, STATE ZIP)) PERSON_TY(‘JOHN SMITH’, ADDRESS_TY(‘57...

SLIDE 19IS Fall 2002 Selecting from Abstract Datatypes SELECT Customer_id, person.name from Customer; SELECT Customer_id, person.address.street from Customer;

SLIDE 20IS Fall 2002 Updating UPDATE Customer SET person.address.city = ‘HART’ where person.address.city = ‘Briant’;

SLIDE 21IS Fall 2002 Functions CREATE [OR REPLACE] FUNCTION funcname (argname [IN | OUT | IN OUT] datatype …) RETURN datatype (IS | AS) {block | external body}

SLIDE 22IS Fall 2002 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...

SLIDE 23IS Fall 2002 Today Traditional and Current Data Administration Traditional and Current Database Administration

SLIDE 24IS Fall 2002 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)

SLIDE 25IS Fall 2002 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

SLIDE 26IS Fall 2002 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

SLIDE 27IS Fall 2002 Database System Life Cycle Operation & Maintenance Database Implementation Database Design Growth & Change Database Analysis Database Planning Note: this is a different version of this life cycle than discussed previously

SLIDE 28IS Fall 2002 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

SLIDE 29IS Fall 2002 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)

SLIDE 30IS Fall 2002 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

SLIDE 31IS Fall 2002 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)

SLIDE 32IS Fall 2002 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.)

SLIDE 33IS Fall 2002 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

SLIDE 34IS Fall 2002 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)

SLIDE 35IS Fall 2002 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

SLIDE 36IS Fall 2002 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)

SLIDE 37IS Fall 2002 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.

SLIDE 38IS Fall 2002 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

SLIDE 39IS Fall 2002 Operation and Maintenance: DA & DBA functions Monitor database performance (DBA) Tune and reorganize databases (DBA) Enforce standards and procedures (DBA) Support users (DA & DBA)

SLIDE 40IS Fall 2002 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

SLIDE 41IS Fall 2002 Growth & Change: DA & DBA functions Implement change control procedures (DA & DBA) Plan for growth and change (DA & DBA) Evaluate new technology (DA & DBA)

SLIDE 42IS Fall 2002 Functions in Database Administration Planning and Design (we have already looked at theses processes in detail) Data Integrity Backup and Recovery Security Management

SLIDE 43IS Fall 2002 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)

SLIDE 44IS Fall 2002 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) JohnMarsha ERROR!

SLIDE 45IS Fall 2002 Concurrency Control: Locking Locking levels –Database –Table –Block or page –Record –Field Types –Shared (S locks) –Exclusive (X locks)

SLIDE 46IS Fall 2002 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... JohnMarsha

SLIDE 47IS Fall 2002 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!

SLIDE 48IS Fall 2002 Concurrency Control Avoiding deadlocks by maintaining tables of potential deadlocks and “backing out” one side of a conflicting transaction

SLIDE 49IS Fall 2002 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

SLIDE 50IS Fall 2002 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 ; –Note: “queries” in Access function as views

SLIDE 51IS Fall 2002 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

SLIDE 52IS Fall 2002 Database Backup and Recovery Backup Journaling (audit trail) Checkpoint facility Recovery manager

SLIDE 53IS Fall 2002 Disaster Recovery Planning Testing and Training Procedures Development Budget & Implement Plan Maintenance Recovery Strategies Risk Analysis From Toigo “Disaster Recovery Planning”

SLIDE 54IS Fall 2002 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

SLIDE 55IS Fall 2002 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

SLIDE 56IS Fall 2002 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

SLIDE 57IS Fall 2002 Offsite Storage of Data Early offsite storage facilities were often intended to survive atomic explosions PRISM International directory Mirror sites (Hot sites)