4.20- Domain Relational Calculus In dbms In Hindi скачать в хорошем качестве

4.20- Domain Relational Calculus In dbms In Hindi

4.20- Domain Relational Calculus In dbms In Hindi PLAYLIST: DBMS - Data Base Management System Tutorials In Hindi | GATE- NET- DBMS Lectures in Hindi    • DBMS Complete Syllabus- All University exa...   Relational Algebra In DBMS | relational algebra database examples | relational database operators    • Relational Algebra In DBMS | relational al...   dbms tutorials, database management system tutorial, database tutorials, relational calculus in dbms, tuple relational calculus, relational calculus in dbms, dbms tutorials, ugc net dbms tutorials, #gatedbmslecturesinhindi, #ugcnetdbmslecturesinhindi, #gatedbmslectures, #ugcnetdbmslectures, #dbmslectures #dbms tutorials Domain Relational Calculus Every query in Domain relational calculus is expressed by a domain calculus expression, which is the basic construct. A domain calculus expression is of the form [ ] D|F(D) or ( , , ..., )|F ( , , ..., ) { dd d dd d 1 2 n n ( 1 2 )} Here, D is a set of domain variables (d1, d2, ..., dn) and F is a formula involving D(d1, d2, ..., dn). The result of this query is the set of all tuples for which the formula is true. The operators used by the Domain relational calculus are same as those used by tuple relational calculus. A tuple relational calculus expression can be converted to a domain calculus expression by replacing each tuple variable by n domain variables, where n is the arity of the tuple variable. 176 Introduction to Database Management System 5.3.2.1 Basic Concepts The definitions of Free variables, Bound variables and Qualified variables are same as in tuple relational calculus. Here, we discuss about other definitions that are different from tuple relational calculus. Atom or Atomic formula : An atom or atomic formula may be in any of the following forms: (i) D ∈ R, where D(d1, d2, ..., dn) is the set of domain variables and R is a relation with n attributes. (ii) X ⊗ Y, where ⊗ is any one of comparison operators and X and Y are domain variables. (iii) X ⊗ Constant or Constant ⊗ X, where constant must be domain compatible. Well formed formula (WFF) : A well formed formula (WFF) is recursively defined to be one of the following: (i) Every atom is a WFF. (ii) If f is a WFF, so are (f) and ¬f. (iii) If f and g are WFF’s, then so are f ∨ g, f ∧ g, f → g. (iv) If f(x) is a WFF and X is free and a domain variable, then ∃X(f(x)) and ∀X(f(x)) are also WFF’s. The major difference between tuple relational calculus and domain relational calculus is that in domain calculus the domain variables are used to represent component of tuples instead of tuples variables used in tuple calculus. Again the relation Employee and Department shown in Figure 5.19 are used for examples on domain relational calculus. 4.1- What Is Relational Algebra | Relational Algebra In DBMS | Relational Operators In DBMS    • 4.1- What Is Relational Algebra In dbms in...   4.2- Relational Operations In Relational Algebra | Relational Algebra- relational database operators    • 4.2- Relational Operations In Relational A...   4.9- Cartesian Product Operation In Relational Algebra | Relational Algebra In DBMS | DBMS Course    • 4.9- Cartesian Product Operation In Relati...   4.10- Division Operation In Relational Algebra In DBMS | Relational Algebra In DBMS | DBMS Course    • 4.10- Division Operation In Relational Alg...   4.11- Join Operation In Relational Algebra In DBMS | Relational Algebra In DBMS | DBMS Course    • 4.11- Join Operation In Relational Algebra...   4.12- Inner Join Theta And Equi Join Operation In Relational Algebra In DBMS | Relational Algebra    • 4.12- Inner Join Theta And Equi Join Opera...   4.13- Inner Join - Natural Join Operation In Relational Algebra In DBMS | Relational Algebra | DBMS    • 4.13- Inner Join - Natural Join Operation ...   4.14- Left Outer Join Operation In Relational Algebra In DBMS | Relational Algebra In DBMS    • 4.14- Left Outer Join Operation In Relatio...   4.15- Right Outer Join Operation In Relational Algebra In DBMS | Relational Algebra In DBMS    • 4.15- Right Outer Join Operation In Relati...