Data Administration and Database Administration University of California
Data Administration and Database Administration University of California, Berkeley School of Information Management and Systems SIMS 257: Database Management IS 257 – Spring 2004. 03. 18 - SLIDE 1
Final Project Requirements • See WWW site: – http: //sims. berkeley. edu/courses/is 257/s 04/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 (Web or Access tools) IS 257 – Spring 2004. 03. 18 - SLIDE 2
Fourth Generation Languages • • 1 st Generation -- Machine Language 2 nd Generation -- Assembly Languages 3 rd Generation -- High-Level Languages 4 th Generation -- Non-Procedural Languages • 5 th Generation -- ? ? Knowledge-based ? ? Natural Language ? ? • Where do Object-Oriented Languages fit? ? IS 257 – Spring 2004. 03. 18 - SLIDE 3
Components of a 4 GL Application Parameters for building routine applications… Data Specification Report Specification Screen Specification Feedback Rules Specification Procedural facility Interpreter IS 257 – Spring 2004 Testing tools/debugger Optimizing compiler 2004. 03. 18 - SLIDE 4
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 IS 257 – Spring 2004. 03. 18 - SLIDE 5
Natural Language Disadvantages of using NL • 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 Appropriate response to the disadvantage • It should be combined with other dialogue contructs that aid in the representation of precise logic and structures James Martin, Fourth Generation Languages, 1985 IS 257 – Spring 2004. 03. 18 - SLIDE 6
Natural Language Disadvantages of using NL • It takes substantial time to key in sentences • Ambiguities are possible • Substantial processing is needed Appropriate response to the disadvantage • 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 IS 257 – Spring 2004. 03. 18 - SLIDE 7
Assumptions and Issues • Why 4 GLs? – Are they still appropriate? – Are they still useful? • Is Cold Fusion a 4 GL? • What about PHP? • Who needs them? IS 257 – Spring 2004. 03. 18 - SLIDE 8
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 – Spring 2004. 03. 18 - SLIDE 9
Object-Relational SQL in ORACLE • CREATE (OR REPLACE) TYPE typename AS OBJECT (attr_name, attr_type, …); • CREATE TABLE OF typename; IS 257 – Spring 2004. 03. 18 - SLIDE 10
Example • CREATE TYPE ANIMAL_TY AS OBJECT (Breed VARCHAR 2(25), Name VARCHAR 2(25), Birthdate DATE); • Creates a new type • CREATE TABLE Animal of Animal_ty; • Creates “Object Table” IS 257 – Spring 2004. 03. 18 - SLIDE 11
Constructor Functions • INSERT INTO Animal values (ANIMAL_TY(‘Mule’, ‘Frances’, TO_DATE(‘ 01 -APR-1997’, ‘DD-MMYYYY’))); • Insert a new ANIMAL_TY object into the table IS 257 – Spring 2004. 03. 18 - SLIDE 12
Selecting from an Object Table • Just use the columns in the object… • SELECT Name from Animal; IS 257 – Spring 2004. 03. 18 - SLIDE 13
More Complex Objects • CREATE TYPE Address_TY as object (Street VARCHAR 2(50), City VARCHAR 2(25), State CHAR(2), zip NUMBER); • CREATE TYPE Person_TY as object (Name VARCHAR 2(25), Address ADDRESS_TY); • CREATE TABLE CUSTOMER (Customer_ID NUMBER, Person PERSON_TY); IS 257 – Spring 2004. 03. 18 - SLIDE 14
What Does the Table Look like? • • • DESCRIBE CUSTOMER; NAME TYPE --------------------------CUSTOMER_ID NUMBER PERSON NAMED TYPE IS 257 – Spring 2004. 03. 18 - SLIDE 15
Inserting • INSERT INTO CUSTOMER VALUES (1, PERSON_TY(‘John Smith’, ADDRESS_TY(‘ 57 Mt Pleasant St. ’, ‘Finn’, ‘NH’, 111111))); IS 257 – Spring 2004. 03. 18 - SLIDE 16
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 – Spring 2004. 03. 18 - SLIDE 17
Selecting from Abstract Datatypes • SELECT Customer_id, person. name from Customer; • SELECT Customer_id, person. address. street from Customer; IS 257 – Spring 2004. 03. 18 - SLIDE 18
Updating • UPDATE Customer SET person. address. city = ‘HART’ where person. address. city = ‘Briant’; IS 257 – Spring 2004. 03. 18 - SLIDE 19
Functions • CREATE [OR REPLACE] FUNCTION funcname (argname [IN | OUT | IN OUT] datatype …) RETURN datatype (IS | AS) {block | external body} IS 257 – Spring 2004. 03. 18 - SLIDE 20
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 – Spring 2004. 03. 18 - SLIDE 21
Lecture Outline • Final Project Requirements • Review – Fourth Generation Languages – Object-Relational Extensions to SQL • Database Administration IS 257 – Spring 2004. 03. 18 - SLIDE 22
Today • Traditional and Current Data Administration • Traditional and Current Database Administration IS 257 – Spring 2004. 03. 18 - SLIDE 23
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 – Spring 2004. 03. 18 - SLIDE 24
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 – Spring 2004. 03. 18 - SLIDE 25
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 – Spring 2004. 03. 18 - SLIDE 26
Database System Life Cycle Database Planning Database Analysis Growth & Change Operation & Maintenance Database Design Database Implementation Note: this is a different version of this life cycle than discussed previously IS 257 – Spring 2004. 03. 18 - SLIDE 27
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 IS 257 – Spring 2004. 03. 18 - SLIDE 28
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 – Spring 2004. 03. 18 - SLIDE 29
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 – Spring 2004. 03. 18 - SLIDE 30
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 – Spring 2004. 03. 18 - SLIDE 31
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 – Spring 2004. 03. 18 - SLIDE 32
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 – Spring 2004. 03. 18 - SLIDE 33
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 – Spring 2004. 03. 18 - SLIDE 34
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 – Spring 2004. 03. 18 - SLIDE 35
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 – Spring 2004. 03. 18 - SLIDE 36
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 – Spring 2004. 03. 18 - SLIDE 37
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 – Spring 2004. 03. 18 - SLIDE 38
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 – Spring 2004. 03. 18 - SLIDE 39
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 – Spring 2004. 03. 18 - SLIDE 40
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 – Spring 2004. 03. 18 - SLIDE 41
Functions in Database Administration • Planning and Design (we have already looked at theses processes in detail) • REVIEW – Data Integrity – Backup and Recovery – Security Management IS 257 – Spring 2004. 03. 18 - SLIDE 42
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 – Spring 2004. 03. 18 - SLIDE 43
No Concurrency Control: Lost updates John Marsha • Read account balance (balance = $1000) • Withdraw $200 (balance = $800) • Withdraw $300 (balance = $700) • Write account balance (balance = $800) • Write account balance (balance = $700) ERROR! IS 257 – Spring 2004. 03. 18 - SLIDE 44
Concurrency Control: Locking • Locking levels – Database – Table – Block or page – Record – Field • Types – Shared (S locks) – Exclusive (X locks) IS 257 – Spring 2004. 03. 18 - SLIDE 45
Concurrency Control: Updates with X locking John • Lock account balance • Read account balance (balance = $1000) • Withdraw $200 (balance = $800) • Write account balance (balance = $800) • Unlock account balance IS 257 – Spring 2004 Marsha • Read account balance (DENIED) • Lock account balance • Read account balance (balance = $800) • etc. . . 2004. 03. 18 - SLIDE 46
Concurrency Control: Deadlocks John Marsha • Place S lock • Read account balance (balance = $1000) • Request X lock (denied) • wait. . . Deadlock! IS 257 – Spring 2004. 03. 18 - SLIDE 47
Concurrency Control • Avoiding deadlocks by maintaining tables of potential deadlocks and “backing out” one side of a conflicting transaction IS 257 – Spring 2004. 03. 18 - SLIDE 48
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 – Spring 2004. 03. 18 - SLIDE 49
Views • A subset of the database presented to some set of users – SQL: CREATE VIEW viewname AS SELECT field 1, field 2, field 3, …, FROM table 1, table 2 WHERE <where clause>; – Note: “queries” in Access function as views IS 257 – Spring 2004. 03. 18 - SLIDE 50
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 – Spring 2004. 03. 18 - SLIDE 51
Database Backup and Recovery • • Backup Journaling (audit trail) Checkpoint facility Recovery manager IS 257 – Spring 2004. 03. 18 - SLIDE 52
Disaster Recovery Planning Risk Analysis Recovery Strategies Plan Maintenance Testing and Training Budget & Implement Procedures Development From Toigo “Disaster Recovery Planning” IS 257 – Spring 2004. 03. 18 - SLIDE 53
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 IS 257 – Spring 2004. 03. 18 - SLIDE 54
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 IS 257 – Spring 2004. 03. 18 - SLIDE 55
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 IS 257 – Spring 2004. 03. 18 - SLIDE 56
Offsite Storage of Data • Early offsite storage facilities were often intended to survive atomic explosions • PRISM International directory • Mirror sites (Hot sites) IS 257 – Spring 2004. 03. 18 - SLIDE 57
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