Moving Objects Databases - Worcester Polytechnic Institute
... Observe that in order for this procedure to produce correct results, we must ensure that F’ and p are satisfied for the same tuple in the cartesian product of the FROM relations. We ensure this by including in the target list of all four queries, a key of each relation in the FROM clause. The above ...
... Observe that in order for this procedure to produce correct results, we must ensure that F’ and p are satisfied for the same tuple in the cartesian product of the FROM relations. We ensure this by including in the target list of all four queries, a key of each relation in the FROM clause. The above ...
Exam 2004 (sat by internal students)
... (2) Consider, now, models (B1) and (B2). When they are transformed into relational models, in both cases, it is possible to use either one single relation that merges the attributes of both entities (due to the one-to-one relationship), or two relations linked via a foreign key. For each case (B1 an ...
... (2) Consider, now, models (B1) and (B2). When they are transformed into relational models, in both cases, it is possible to use either one single relation that merges the attributes of both entities (due to the one-to-one relationship), or two relations linked via a foreign key. For each case (B1 an ...
DBsMM - Berkeley Database Group
... Relational Algebra • Basic operations: – Selection ( ) Selects a subset of rows from relation. – Projection (p ) Deletes unwanted columns from relation. – Cross-product ( ) Allows us to combine two relations. – Set-difference ( ) Tuples in reln. 1, but not in reln. 2. – Union ( ) Tuples in reln. ...
... Relational Algebra • Basic operations: – Selection ( ) Selects a subset of rows from relation. – Projection (p ) Deletes unwanted columns from relation. – Cross-product ( ) Allows us to combine two relations. – Set-difference ( ) Tuples in reln. 1, but not in reln. 2. – Union ( ) Tuples in reln. ...
DATABASES - Computer Science
... We store each employee's Name, Ssn, Address, Salary, Sex, and Birth Date. An employee is ASSIGNED to one department but may WORK ON several projects, which are not necessarily CONTROLLED by the same department. We store the number of Hours per week that an employee works on each project. Each employ ...
... We store each employee's Name, Ssn, Address, Salary, Sex, and Birth Date. An employee is ASSIGNED to one department but may WORK ON several projects, which are not necessarily CONTROLLED by the same department. We store the number of Hours per week that an employee works on each project. Each employ ...
eLL
... Introduction to SQL • SQL = Structured Query Language • (DML – Data Manipulation Language included) • A declarative programming language (telling the computer what to do – not how to do it by means of algoritms like imperative programming languages) SQL tells the database management system what t ...
... Introduction to SQL • SQL = Structured Query Language • (DML – Data Manipulation Language included) • A declarative programming language (telling the computer what to do – not how to do it by means of algoritms like imperative programming languages) SQL tells the database management system what t ...
Chapter 6: Logical database design and the relational model
... * Remember! The Relational database does not like any type of redundancy. Every table must have a unique name. Attributes in tables must have unique names. Every attribute value is atomic. The order of the columns is irrelevant. The order of the rows is irrelevant. ...
... * Remember! The Relational database does not like any type of redundancy. Every table must have a unique name. Attributes in tables must have unique names. Every attribute value is atomic. The order of the columns is irrelevant. The order of the rows is irrelevant. ...
BUSINESS DRIVEN TECHNOLOGY, 2e
... required by the DBMS • Most database installations are based on the relational data model • The relational data model is the result of the work of one person, Edgar (E. F.) Codd ...
... required by the DBMS • Most database installations are based on the relational data model • The relational data model is the result of the work of one person, Edgar (E. F.) Codd ...
Technology Plug-In PPT 5 - McGraw Hill Higher Education
... • The structure of a relational database is stored in the database's data dictionary, or catalog • The data dictionary is made up of a set of relations, identical in properties to the relations used to hold data • Information found in a data dictionary: – Definitions of the columns that make up each ...
... • The structure of a relational database is stored in the database's data dictionary, or catalog • The data dictionary is made up of a set of relations, identical in properties to the relations used to hold data • Information found in a data dictionary: – Definitions of the columns that make up each ...
Reverse engineering of relational database applications
... current work (e.g. [2,3,7]) is concerned with the structural side of such views only, i.e. the translation of a relational schema into a corresponding object structure. While such views are adequate as an interface for data interchange, they neglect the additional possibility of the object-oriented ...
... current work (e.g. [2,3,7]) is concerned with the structural side of such views only, i.e. the translation of a relational schema into a corresponding object structure. While such views are adequate as an interface for data interchange, they neglect the additional possibility of the object-oriented ...
Chp4: Relational Algebra
... All of these operations take two input relations, which must be union-compatible: Same number of fields. `Corresponding’ fields have the same type. What is the schema of result? ...
... All of these operations take two input relations, which must be union-compatible: Same number of fields. `Corresponding’ fields have the same type. What is the schema of result? ...
Introduction to Structured Query Language
... l Each field is complete value (no pointers or derived values). l An empty field has a well defined value: null. Null is not the same as an empty string or zero—null is a distinct value. ...
... l Each field is complete value (no pointers or derived values). l An empty field has a well defined value: null. Null is not the same as an empty string or zero—null is a distinct value. ...
SQL QUERY EVALUATION
... (Can’t add to MySQL easily, since it doesn’t use relational algebra as a query-plan representation…) ...
... (Can’t add to MySQL easily, since it doesn’t use relational algebra as a query-plan representation…) ...
Chapter 17
... clause that identifies ‘compiled code’ in operating system’s file storage. ORDBMS will provide method to dynamically link this object file into the DBMS so that it can be invoked when required. Procedure for this is outside bounds of SQL standard and is left as implementation-defined. ...
... clause that identifies ‘compiled code’ in operating system’s file storage. ORDBMS will provide method to dynamically link this object file into the DBMS so that it can be invoked when required. Procedure for this is outside bounds of SQL standard and is left as implementation-defined. ...
dbms with answer
... A) You can join a maximum of two tables through an equijoin. B) You can join a maximum of two columns through an equijoin. C) You specify an equijoin condition in the SELECT or FROM clauses of a SELECT statement. D) You can join n tables (all having single column primary keys) in a SQL statement by ...
... A) You can join a maximum of two tables through an equijoin. B) You can join a maximum of two columns through an equijoin. C) You specify an equijoin condition in the SELECT or FROM clauses of a SELECT statement. D) You can join n tables (all having single column primary keys) in a SQL statement by ...
Database Introduction -2
... However, 'X23Y B&&9' is also a string but is not a student name. (unless that student has particularly annoying parents). ...
... However, 'X23Y B&&9' is also a string but is not a student name. (unless that student has particularly annoying parents). ...
CSC271 Database Systems
... On the other hand, the relationship between position and staffNo is one-to-many (1:*): there are several staff numbers associated with a given position For the purposes of normalization we are interested in identifying functional dependencies between attributes of a relation that have a one-to-one r ...
... On the other hand, the relationship between position and staffNo is one-to-many (1:*): there are several staff numbers associated with a given position For the purposes of normalization we are interested in identifying functional dependencies between attributes of a relation that have a one-to-one r ...
IS 331 Database Design, Management and Applications Fall 2015
... Dashboard & Scorecard, and Data Warehouses. Since database plays such a crucial role in business operations of any modern organizations, an IS professional must understand how to plan, design, implement and manage database systems. This course gives students extensive, pragmatic experience in design ...
... Dashboard & Scorecard, and Data Warehouses. Since database plays such a crucial role in business operations of any modern organizations, an IS professional must understand how to plan, design, implement and manage database systems. This course gives students extensive, pragmatic experience in design ...
Database System Concepts, 6 th Ed
... Some Updates cannot be Translated Uniquely create view instructor_info as ...
... Some Updates cannot be Translated Uniquely create view instructor_info as ...
while new - UHasselt
... • There is a PTIME BGS-program that outputs: – true on every In with n even; – false odd. (Just construct all red subsets of even size.) Theorem: There is no such PSPACE whilenewprogram (let alone PTIME). ...
... • There is a PTIME BGS-program that outputs: – true on every In with n even; – false odd. (Just construct all red subsets of even size.) Theorem: There is no such PSPACE whilenewprogram (let alone PTIME). ...
