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Data Modeling Techniques: ER, SADT, and UML Overview

This article explores essential data modeling techniques, including Entity-Relationship (ER) diagrams, Structured Analysis and Design Technique (SADT), and Unified Modeling Language (UML). We delve into the creation of databases using ER concepts with examples of table creation and relationships, as well as using UML for various diagrams like use case, activity, and class diagrams. Additionally, we touch on XML as a self-describing format and its application in data modeling. Finally, we provide Python code snippets for database manipulation, enhancing understanding of data processing and analysis.

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Data Modeling Techniques: ER, SADT, and UML Overview

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  1. Data Modeling • ER • SADT • UML

  2. Data Modeling: ER • Entity-relationship diagram • Entity: attributes • Relationship: (smth)-(smth)

  3. Data Modeling: ER CREATE TABLE ID (HD INTEGER NOT NULL, BD INTEGER, CONSTRAINT hd_pk PRIMARY KEY (HD)) CREATE TABLE ProperMotion (HD INTEGER NOT NULL, PMX DOUBLE, PMY DOUBLE, CONSTRAIN hd_fk FOREIN KEY (HD) REFERENCES hd_pk) SELECT T1.HD, T1.BD, T2.PMX, T2.PMY FROM ID T1, ProperMotion T2 where T2.HD=T1.HD

  4. SADT • Structured Analysis and Design Technique • Integration Definition for Function Modeling -0 • Simple 2-elements diagram

  5. SADT

  6. SADT

  7. UML: Unified Modeling Language • SW design • Data processing design • Design → Implementation • Object-oriented approarch • Database design

  8. UML: Use Case Diagram • Actor • Use Case • First step in developing • Define use cases • Do not go in details

  9. UML: Activity Diagram • Initial State • Activity • Final (End) State • Connector (Fork/Union)

  10. UML: Interaction Diagram • Object (participant) • Lifeline • Message

  11. UML: Class Diagram • Class • Object • Relashionship

  12. UML: diagrams • Package diagram • Component diagram • Deployment diagram • Statechart diagram

  13. Data Modeling: UML • the same primitives for another purposes • data processing diagram of classes diagram of tables

  14. XML • Extensible Markup Language • Self-describing format • Standard Generalized Markup Language • HTML • XML Schema • XSLT

  15. XML: structure • Node (Element) • Text • Attributes

  16. Python • Python language www.python.org • Object-oriented, modular, API • language-interpreter • Functions def • Classes class

  17. Python: an example from math import pi, sin, cos, sqrt, asin, atan, atan2 from astro.util.extinction import p2i class IDLLibError(Exception): pass def total(a,b): try: if(len(a)!=len(b)): raise IDLLibError, 'total: the same size for input matrix' except: raise IDLLibError, 'total: input are two matrix of the same size' x=0.0 for i in range(len(a)): x=x+a[i]*b[i] return x

  18. Python: an example import MySQLdb conn = MySQLdb.connect(host = "localhost",user = "root",passwd = "", unix_socket="/home/belikov/mysql/mysql.sock", read_default_file="/home/belikov/mysql/my.cnf") cursor = conn.cursor () cursor.execute ("DROP DATABASE PROB") cursor.execute ("CREATE DATABASE PROB") cursor.execute ("USE PROB") cursor.execute ("CREATE TABLE TWOMASS (RA DOUBLE, DECL DOUBLE)") cursor.close () conn.close ()

  19. R • Language for wrapping statistical computing • Site: www.r-project.org • Arrays • Plotting • Aggregate functions

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