bar - KTH
... The bar and beer together are the key for Sells: CREATE TABLE Sells ( bar CHAR(20), beer VARCHAR(20), price REAL, PRIMARY KEY (bar, beer) ...
... The bar and beer together are the key for Sells: CREATE TABLE Sells ( bar CHAR(20), beer VARCHAR(20), price REAL, PRIMARY KEY (bar, beer) ...
Chapter 3 - WordPress.com
... or types of relations are Named and Unnamed Relations. The basic difference is on how the relation is created, used and updated: – Base Relation • A Named Relation corresponding to an entity in the conceptual schema, whose tuples are physically stored in the database. ...
... or types of relations are Named and Unnamed Relations. The basic difference is on how the relation is created, used and updated: – Base Relation • A Named Relation corresponding to an entity in the conceptual schema, whose tuples are physically stored in the database. ...
Module 1 – Background - Dalhousie University
... – A view is a virtual relation that does not necessarily exist in the database but can be produced upon request by a particular user, at the time of the request – Not all views are updatable. ...
... – A view is a virtual relation that does not necessarily exist in the database but can be produced upon request by a particular user, at the time of the request – Not all views are updatable. ...
Introduction
... The bar and beer together are the key for Sells: CREATE TABLE Sells ( bar CHAR(20), beer ...
... The bar and beer together are the key for Sells: CREATE TABLE Sells ( bar CHAR(20), beer ...
homework 5: Object-Oriented Databases
... the student-course-TA example for ODMG handout in class) for the following object classes: project, document, project-leader, research-paper and dbresearch-paper. Use document-IF as an interface class for document, document is a subclass of document-IF and research-paper is a subclass of document. d ...
... the student-course-TA example for ODMG handout in class) for the following object classes: project, document, project-leader, research-paper and dbresearch-paper. Use document-IF as an interface class for document, document is a subclass of document-IF and research-paper is a subclass of document. d ...
Data Warehousing – CG124
... Assess different ways of extending the relational model and SQL (e.g object-relational extensions, PL/SQL); Explain, discuss, and evaluate Object-Oriented databases; Compare and contrast the relational data model with objectrelational and object-oriented data models; Critically evaluate query optimi ...
... Assess different ways of extending the relational model and SQL (e.g object-relational extensions, PL/SQL); Explain, discuss, and evaluate Object-Oriented databases; Compare and contrast the relational data model with objectrelational and object-oriented data models; Critically evaluate query optimi ...
6_Chapter05 - An
... Any key is a superkey (but not vice versa) Any set of attributes that includes a key is a superkey A minimal superkey is also a key Slide 5- 19 ...
... Any key is a superkey (but not vice versa) Any set of attributes that includes a key is a superkey A minimal superkey is also a key Slide 5- 19 ...
Chapter 17: Parallel Databases
... useful with a lower degree of parallelism. less useful in a highly parallel system. ...
... useful with a lower degree of parallelism. less useful in a highly parallel system. ...
Chapter 17: Parallel Databases
... useful with a lower degree of parallelism. less useful in a highly parallel system. ...
... useful with a lower degree of parallelism. less useful in a highly parallel system. ...
Data model
... Column, or set of columns, within one table that matches candidate key of some (possibly same) table. ...
... Column, or set of columns, within one table that matches candidate key of some (possibly same) table. ...
Day 5 - More Complexity With Queries
... – 1st: It finds the tables/joined tables it needs in the FROM ...
... – 1st: It finds the tables/joined tables it needs in the FROM ...
Data Models - Assignment Point
... A database cannot contain a tuple with a value for a foreign key that does not match a primary key value in the referenced relation. Or, a foreign key must refer to a tuple that exists. ...
... A database cannot contain a tuple with a value for a foreign key that does not match a primary key value in the referenced relation. Or, a foreign key must refer to a tuple that exists. ...
Object Relational Databases - West University of Timișoara
... A relation is in 3NF iff it is in 2NF and no nonkey attribute is transitively dependent on the key A relation is 2NF iff it is in 1NF and all the non-key attributes are fully FD on the key A relation is 1NF iff every attribute is single-valued for each tuple. ...
... A relation is in 3NF iff it is in 2NF and no nonkey attribute is transitively dependent on the key A relation is 2NF iff it is in 1NF and all the non-key attributes are fully FD on the key A relation is 1NF iff every attribute is single-valued for each tuple. ...
Basic Concepts of Relational Database
... A relation schema may have more than 1 key. Each of the keys is called a candidate key. One of the candidate keys are designated as the primary key of the relation. ...
... A relation schema may have more than 1 key. Each of the keys is called a candidate key. One of the candidate keys are designated as the primary key of the relation. ...
Convert ER Design to Relations - csns
... Proposed by Edgar F. Codd in early 1970’s Data is stored in tables (a.k.a. relations) All major database systems these day are relational student_id ...
... Proposed by Edgar F. Codd in early 1970’s Data is stored in tables (a.k.a. relations) All major database systems these day are relational student_id ...
Fundamentals of Database Systems
... The most common use of join involves join conditions with equality comparisons only. Such a join, where the only comparison operator used is =, is called an EQUIJOIN. In the result of an EQUIJOIN we always have one or more pairs of attributes (whose names need not be identical) that have identical v ...
... The most common use of join involves join conditions with equality comparisons only. Such a join, where the only comparison operator used is =, is called an EQUIJOIN. In the result of an EQUIJOIN we always have one or more pairs of attributes (whose names need not be identical) that have identical v ...
Connolly chap2
... Terminology of relational data model. How tables are used to represent data. Properties of database relations. How to identify candidate, primary, and foreign keys. Meaning of entity integrity and referential integrity. © Pearson Education Limited, ...
... Terminology of relational data model. How tables are used to represent data. Properties of database relations. How to identify candidate, primary, and foreign keys. Meaning of entity integrity and referential integrity. © Pearson Education Limited, ...
The essence of data normalization is to spit the data into several
... The goal of any information system is to add value for the user. The process of determining the proper tables for a database is called Organizations. The essence of data normalization is to spit the data into several filed. Primary key is a column or set of columns that identifies particular column. ...
... The goal of any information system is to add value for the user. The process of determining the proper tables for a database is called Organizations. The essence of data normalization is to spit the data into several filed. Primary key is a column or set of columns that identifies particular column. ...
Relational Algebra - Philadelphia University
... The most common use of join involves join conditions with equality comparisons only. Such a join, where the only comparison operator used is =, is called an EQUIJOIN. In the result of an EQUIJOIN we always have one or more pairs of attributes (whose names need not be identical) that have identical v ...
... The most common use of join involves join conditions with equality comparisons only. Such a join, where the only comparison operator used is =, is called an EQUIJOIN. In the result of an EQUIJOIN we always have one or more pairs of attributes (whose names need not be identical) that have identical v ...
Knowing Just Enough about Relational Databases
... an instance of the entity Employee. (In the OO world, Doug would be an object in the Employee class.) Attribute: This word is used in both relational and OO databases to represent information about an entity instance or an object that will be tracked. An example of an attribute might be the birth da ...
... an instance of the entity Employee. (In the OO world, Doug would be an object in the Employee class.) Attribute: This word is used in both relational and OO databases to represent information about an entity instance or an object that will be tracked. An example of an attribute might be the birth da ...