10/25/2001Database Management -- R. Larson Data Administration and Database Administration University of California, Berkeley School of Information Management and Systems SIMS 257: Database Management

10/25/2001Database Management -- R. Larson Mid-Term Assignment #5 See WWW site: – Report on personal database including: –Database description –Data Dictionary –Relationships Diagram –Sample queries and results –Sample forms –Sample reports

10/25/2001Database Management -- R. Larson Today Data Administration Database Administration

10/25/2001Database Management -- R. Larson Terms and Concepts 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 Data Steward –Responsibility for some subset of the organization’s data, and all of the interactions (applications, user access, etc.) for that data

10/25/2001Database Management -- R. Larson Terms and Concepts 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

10/25/2001Database Management -- R. Larson 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

10/25/2001Database Management -- R. Larson 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.

10/25/2001Database Management -- R. Larson 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)

10/25/2001Database Management -- R. Larson 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.

10/25/2001Database Management -- R. Larson 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)

10/25/2001Database Management -- R. Larson 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.)

10/25/2001Database Management -- R. Larson 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

10/25/2001Database Management -- R. Larson 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)

10/25/2001Database Management -- R. Larson 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

10/25/2001Database Management -- R. Larson 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)

10/25/2001Database Management -- R. Larson 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.

10/25/2001Database Management -- R. Larson 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

10/25/2001Database Management -- R. Larson Operation and Maintenance: DA & DBA functions Monitor database performance (DBA) Tune and reorganize databases (DBA) Enforce standards and procedures (DBA) Support users (DA & DBA)

10/25/2001Database Management -- R. Larson 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.

10/25/2001Database Management -- R. Larson Growth & Change: DA & DBA functions Implement change control procedures (DA & DBA) Plan for growth and change (DA & DBA) Evaluate new technology (DA & DBA)

10/25/2001Database Management -- R. Larson Issues/functions in Database Administration Planning and Design (we have already looked at theses processes in detail) Data Integrity Backup and Recovery Security Management

10/25/2001Database Management -- R. Larson 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).

10/25/2001Database Management -- R. Larson 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!

10/25/2001Database Management -- R. Larson Concurrency Control: Locking Locking levels –Database –Table –Block or page –Record –Field Types –Shared (S locks) –Exclusive (X locks)

10/25/2001Database Management -- R. Larson 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

10/25/2001Database Management -- R. Larson 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!

10/25/2001Database Management -- R. Larson Concurrency Control Avoiding deadlocks by maintaining tables of potential deadlocks and “backing out” one side of a conflicting transaction.

10/25/2001Database Management -- R. Larson 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

10/25/2001Database Management -- R. Larson 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.

10/25/2001Database Management -- R. Larson 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.

10/25/2001Database Management -- R. Larson Database Backup and Recovery Backup Journaling (audit trail) Checkpoint facility Recovery manager

10/25/2001Database Management -- R. Larson Disaster Recovery Planning Testing and Training Procedures Development Budget & Implement Plan Maintenance Recovery Strategies Risk Analysis From Toigo “Disaster Recovery Planning”

10/25/2001Database Management -- R. Larson Terms and Concepts 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 Data Steward –Responsibility for some subset of the organization’s data, and all of the interactions (applications, user access, etc.) for that data

10/25/2001Database Management -- R. Larson Issues/functions in Database Administration Planning and Design (we have already looked at theses processes in detail) Data Integrity Backup and Recovery Security Management

10/25/2001Database Management -- R. Larson Today Additional issues –Handling special data considerations –Database/Data Dictionary –Database Building in SQL (maybe)