L8  components and properties of dbms
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L8 components and properties of dbms

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L8  components and properties of dbms L8 components and properties of dbms Presentation Transcript

  • Components of DBMS Properties of DBMS Version 1.1 Rushdi Shams, Dept of CSE, KUET 1
  • File Processing System Rushdi Shams, Dept of CSE, KUET 2 Checking Account Programs Auto Loan Programs Savings Account Programs Checking Account Data Files Savings Account Data Files Auto Loan Data Files
  • Database Processing System Rushdi Shams, Dept of CSE, KUET 3 Database Management System Checking Account Programs Auto Loan Programs Savings Account Programs Database
  • How DBMS Works Rushdi Shams, Dept of CSE, KUET 4 SQL PLUS Fetching Code Code in HDD ORACLE DBMS Plan-> Runs-> Compiles ->Result set Code fetched
  • How DBMS Works Rushdi Shams, Dept of CSE, KUET 5 JAVA Code { String( “select …”); } Fetching Code Code fetched ORACLE DBMS Plan-> Runs-> Compiles ->Result set JDBC
  • Components of DBMS 1. Models  Hierarchical model  Network model and  Relational model Rushdi Shams, Dept of CSE, KUET 6
  • Components of DBMS (continued) 2. Data structures This defines the properties of several aspects of rows/records and columns/fields, etc Rushdi Shams, Dept of CSE, KUET 7
  • Components of DBMS (continued) 3. A query language allow users to interactively interrogate the database, analyse its data and update it according to the user privileges on data so, you can say query language actually provides  Analysis on data  Interrogation on data  Security on data Rushdi Shams, Dept of CSE, KUET 8
  • Components of DBMS (continued) 4. Transaction Mechanism Transaction means data moving between two or more databases. It provides ACID property. In case of database systems, ACID stands for  Atomicity  Consistency  Isolation and  Durability Rushdi Shams, Dept of CSE, KUET 9
  • Components of DBMS (continued)  Atomicity It is the ability of the DBMS that ensures either all of the transactions take place or none of them take place! Kind of weird, huh? Well, let me give an example. If a bank account is debited, another bank account must be credited- that is called atomicity! Rushdi Shams, Dept of CSE, KUET 10
  • Components of DBMS (continued)  Consistency Every database has some rules according to the organization to which it belongs. This property ensures that the databases are in legal state after a transaction takes place. For example, if a bank says that its client’s account balance can never be negative, then no such transaction will take place that makes a balance negative. Rushdi Shams, Dept of CSE, KUET 11
  • Components of DBMS (continued)  Isolation This property ensures that no other operation can intervene the transaction operation. For example, a bank manager, during a transaction should be able to see balance of one account, not on both. This is the most relaxed option in ACID properties. Rushdi Shams, Dept of CSE, KUET 12
  • Components of DBMS (continued)  Durability This property ensures that once a transaction takes place, it cannot be undone. when an account to account transfer takes place, after completion, it should notify the user that transaction successfully done and you cannot rewind that! Rushdi Shams, Dept of CSE, KUET 13
  • Properties of Database  Data Sharing  Data Integration  Data Security  Data Abstraction  Data Independence Rushdi Shams, Dept of CSE, KUET 14
  • Data Sharing  Do you think records are kept to be used by only one person? Or, should it be shared, so that we can use it? Rushdi Shams, Dept of CSE, KUET 15
  • Data Integration  This implies that a database should be a collection of data which, at least ideally, has no redundant data.  Redundant data is unnecessarily duplicated data.  A data value is redundant when an attribute has two or more identical values.  A data value is redundant if you can delete it without information being lost. Rushdi Shams, Dept of CSE, KUET 16
  • Data Integrity  The database should accurately reflect the universe of discourse that it is attempting to model.  if relationships exist in the real world between objects represented by data in a database then changes made to one partner in such a relationship should be accurately reflected in changes made to other partners in that relationship Rushdi Shams, Dept of CSE, KUET 17
  • Data Security  One of the major ways of ensuring the integrity of a database is by restricting access – in other words, securing the database.  Define a set of authorised users of the whole, or more usually parts, of the database. Rushdi Shams, Dept of CSE, KUET 18
  • Data Abstraction  An academic database is meant to record relevant details of university activity. We say relevant, because no database can store all the properties of real-world objects. A database is therefore an abstraction of the real world Rushdi Shams, Dept of CSE, KUET 19
  • Data Independence  If a change is made to some part of the underlying database, no application programs using affected data should need to be changed.  Also, if a change is made to some part of an application system then this should not affect the structure of the underlying data used by the application. Rushdi Shams, Dept of CSE, KUET 20