If you were designing a Web-based system to make airline reservations and to sell airline tickets, which DBMS Architecture would you choose from Section 2

If you were designing a Web-based system to make airline reservations and to sell airline tickets, which DBMS Architecture would you choose from Section 2.5? Why? Why would the other architectures not be a good choice?

Paper Should be:

Discussion should be 250-300 words.

Should have APA citation and at least 1 scholarly reference.

No plagiarism

Add 2 discussion comments on the same topic 100 words each.

Database System Concepts and Architecture Dr. Buleje Slide 1- 1 Outline ? ? ? ? ? ? ? ? ? Data Models and Their Categories Schemas, Instances, and States Three-Schema Architecture Data Independence DBMS Languages and Interfaces Database System Utilities and Tools Database System Environment Centralized and Client-Server Architectures Classification of DBMSs Slide 2- 2 Data Models ? ? ? Data Model Data Model Structure and Constraints Data Model Operations Slide 2- 3 Categories of Data Models ? ? ? ? Conceptual (high-level, semantic) data models Physical (low-level, internal) data models Implementation (representational) data models Self-Describing Data Models Slide 2- 4 Schemas versus Instances ? ? ? ? Database Schema Schema Diagram Schema Construct Database State Slide 2- 5 Database Schema vs. Database State ? ? ? ? Database State Initial Database State Valid State Distinction Slide 2- 6 Example of a Database Schema Slide 2- 7 Example of a database state Slide 2- 8 Three-Schema Architecture ? ? Support DBMS characteristics of: ? Program-data independence. ? Multiple views Support , around data. Defines DBMS schemas at three levels: ? Internal schema ? Conceptual schema ? External schemas Slide 2- 9 The three-schema architecture Slide 2- 10 DBMS Languages ? ? Data Definition Language (DDL) Data Manipulation Language (DML) ? ? High Level or Non-procedural Language Low Level or Procedural Language Slide 2- 11 DBMS Interfaces ? ? ? ? Stand-alone query language interfaces Programmer interfaces for embedding DML in programming languages User-friendly interfaces Mobile Interfaces Slide 2- 12 DBMS Programming Language Interfaces ? Programmer interfaces for embedding DML in a programming languages: ? ? ? ? Embedded Approach Procedure Call Approach Database Programming Language Approach Scripting Languages Slide 2- 13 User-Friendly DBMS Interfaces ? ? ? ? ? Menu-based (Web-based), Forms-based Graphics-based Natural language Combinations of the above Slide 2- 14 Other DBMS Interfaces ? ? ? ? ? Natural language Speech Web Browser with keyword search Parametric interfaces Interfaces for the DBA Slide 2- 15 Database System Utilities ? To perform certain functions such as: ? ? ? ? ? ? Loading data stored in files into a database. Backing up the database Reorganizing database file Performance monitoring Report generation Other functions Slide 2- 16 Centralized and Client-Server DBMS Architectures ? Centralized DBMS Slide 2- 17 A Physical Centralized Architecture Slide 2- 18 Basic 2-tier Client-Server Architectures ? Specialized Servers with Specialized functions ? ? ? ? ? ? ? Print server File server DBMS server Web server Email server CLIENTS DBMS Server Slide 2- 19 Logical two-tier client server architecture Slide 2- 20 Tier Client-Server Architecture ? ? Two Tier Client Server Architecture Three Tier Client Server Architecture Slide 2- 21 Classification of DBMSs ? ? Based on the data model used. Other classifications Slide 2- 22 Cost considerations for DBMSs ? ? Cost Range Examples of free relational DBMSs: ? ? ? ? ? MySQL PostgreSQL others Commercial DBMS Different licensing options Slide 2- 23 Chapter Summary ? ? ? ? ? ? ? ? ? Data Models and Their Categories Schemas, Instances, and States Three-Schema Architecture Data Independence DBMS Languages and Interfaces Database System Utilities and Tools Database System Environment Centralized and Client-Server Architectures Classification of DBMSs Slide 2- 24 BACK UP SLIDES (SUPPLEMENTAL MATERIAL) Slide 2- 25 History of Data Models (Additional Material) ? ? ? ? ? Network Model Hierarchical Model Relational Model Object-oriented Data Models Object-Relational Models Slide 2- 26 History of Data Models ? Network Model: ? ? ? The first network DBMS was implemented by Honeywell in 1964-65 (IDS System). Adopted heavily due to the support by CODASYL (Conference on Data Systems Languages) (CODASYL - DBTG report of 1971). Later implemented in a large variety of systems IDMS (Cullinet - now Computer Associates), DMS 1100 (Unisys), IMAGE (H.P. (Hewlett-Packard)), VAX -DBMS (Digital Equipment Corp., next COMPAQ, now H.P.). Slide 2- 27 Network Model ? Advantages: ? ? ? Network Model is able to model complex relationships and represents semantics of add/delete on the relationships. Can handle most situations for modeling using record types and relationship types. Language is navigational; uses constructs like FIND, FIND member, FIND owner, FIND NEXT within set, GET, etc. ? Programmers can do optimal navigation through the database. Slide 2- 28 Network Model ? Disadvantages: ? ? Navigational and procedural nature of processing Database contains a complex array of pointers that thread through a set of records. ? Little scope for automated “query optimization” Slide 2- 29 History of Data Models ? Hierarchical Data Model: ? ? ? ? Initially implemented in a joint effort by IBM and North American Rockwell around 1965. Resulted in the IMS family of systems. IBM’s IMS product had (and still has) a very large customer base worldwide Hierarchical model was formalized based on the IMS system Other systems based on this model: System 2k (SAS inc.) Slide 2- 30 Hierarchical Model ? Advantages: ? ? ? Simple to construct and operate Corresponds to a number of natural hierarchically organized domains, e.g., organization (“org”) chart Language is simple: ? ? Uses constructs like GET, GET UNIQUE, GET NEXT, GET NEXT WITHIN PARENT, etc. Disadvantages: ? ? ? Navigational and procedural nature of processing Database is visualized as a linear arrangement of records Little scope for "query optimization" Slide 2- 31 History of Data Models ? Relational Model: ? ? ? ? ? ? Proposed in 1970 by E.F. Codd (IBM), first commercial system in 1981-82. Now in several commercial products (e.g. DB2, ORACLE, MS SQL Server, SYBASE, INFORMIX). Several free open source implementations, e.g. MySQL, PostgreSQL Currently most dominant for developing database applications. SQL relational standards: SQL-89 (SQL1), SQL-92 (SQL2), SQL-99, SQL3, … Chapters 5 through 11 describe this model in detail Slide 2- 32 History of Data Models ? Object-oriented Data Models: ? ? ? ? ? Several models have been proposed for implementing in a database system. One set comprises models of persistent O-O Programming Languages such as C++ (e.g., in OBJECTSTORE or VERSANT), and Smalltalk (e.g., in GEMSTONE). Additionally, systems like O2, ORION (at MCC - then ITASCA), IRIS (at H.P.- used in Open OODB). Object Database Standard: ODMG-93, ODMG-version 2.0, ODMG-version 3.0. Chapter 12 describes this model. Slide 2- 33 History of Data Models ? Object-Relational Models: ? ? ? ? ? The trend to mix object models with relational was started with Informix Universal Server. Relational systems incorporated concepts from object databases leading to object-relational. Exemplified in the versions of Oracle, DB2, and SQL Server and other DBMSs. Current trend by Relational DBMS vendors is to extend relational DBMSs with capability to process XML, Text and other data types. The term “Object-relational” is receding in the marketplace.