Chapter 7
... Dynamic result of one or more relational operations operating on base relations to produce another relation. ...
... Dynamic result of one or more relational operations operating on base relations to produce another relation. ...
Mapping ER to Relational Model
... – FK’s based on surrogate keys have no meaning to users – When data shared among different databases contain the same ID, merging those tables might yield unexpected results ...
... – FK’s based on surrogate keys have no meaning to users – When data shared among different databases contain the same ID, merging those tables might yield unexpected results ...
Database Management System
... A table can represent relationships between objects. The Rents table relates Customers to the Movies they’ve rented, by their respective IDs. ...
... A table can represent relationships between objects. The Rents table relates Customers to the Movies they’ve rented, by their respective IDs. ...
The Relational Model
... IC: condition that must be true for any instance of the database. – ICs are specified when schema is defined (by whom?) – ICs are checked when relations are modified ...
... IC: condition that must be true for any instance of the database. – ICs are specified when schema is defined (by whom?) – ICs are checked when relations are modified ...
Query Joins
... columns and marks the fields he or she wants to include in the answer. • Defaults are available for summarizing and manipulating the data. ...
... columns and marks the fields he or she wants to include in the answer. • Defaults are available for summarizing and manipulating the data. ...
Chapter 1 Computer Basics
... • A database management system defines, creates, and maintains a database. • It also allows users controlled access to data in the database. ...
... • A database management system defines, creates, and maintains a database. • It also allows users controlled access to data in the database. ...
CS257_Sec1_118_PPT2_Chapter_15.1
... Sorting While Scanning Tables • Why do we need sorting while scanning? – the query could include an ORDER BY clause. Requiring that a relation be sorted – Various algorithms for relational-algebra operations require one or both of their arguments to be sorted relation – physical-query-plan operator ...
... Sorting While Scanning Tables • Why do we need sorting while scanning? – the query could include an ORDER BY clause. Requiring that a relation be sorted – Various algorithms for relational-algebra operations require one or both of their arguments to be sorted relation – physical-query-plan operator ...
L8- The GIS Database
... table and you'll find that each column of the table corresponds to a specific employee characteristic (or attribute in database terms). Each row corresponds to one particular employee and contains his or her information. ...
... table and you'll find that each column of the table corresponds to a specific employee characteristic (or attribute in database terms). Each row corresponds to one particular employee and contains his or her information. ...
Relational Model Powerpoint
... Data type constraint Each attribute in a tuple may only take on a value from the domain of that attribute ...
... Data type constraint Each attribute in a tuple may only take on a value from the domain of that attribute ...
Candidate Key
... Data Query Language (DQL) Statements that query the database but do not alter any data or database objects. This category contains the SELECT statement. Not all vendors make a distinction here; many lump DQL into DML, as defined next. Data Manipulation Language (DML) Statements that modify data ...
... Data Query Language (DQL) Statements that query the database but do not alter any data or database objects. This category contains the SELECT statement. Not all vendors make a distinction here; many lump DQL into DML, as defined next. Data Manipulation Language (DML) Statements that modify data ...
notes #5
... • Relation name is distinct from all other relation names in relational schema. • Each cell of relation contains exactly one atomic (single) value. • Each attribute has a distinct name. • Values of an attribute are all from the same ...
... • Relation name is distinct from all other relation names in relational schema. • Each cell of relation contains exactly one atomic (single) value. • Each attribute has a distinct name. • Values of an attribute are all from the same ...
Document
... The attributes in the resulting relation are a subset of the attributes in the original relation. ...
... The attributes in the resulting relation are a subset of the attributes in the original relation. ...
Document
... The degree of relational completeness can be defined by the extent to which relational algebra is supported. Relational algebra defines the theoretical way of manipulating table contents using the eight relational functions: SELECT, PROJECT, JOIN, INTERSECT, UNION, DIFFERENCE, PRODUCT, and DIVID ...
... The degree of relational completeness can be defined by the extent to which relational algebra is supported. Relational algebra defines the theoretical way of manipulating table contents using the eight relational functions: SELECT, PROJECT, JOIN, INTERSECT, UNION, DIFFERENCE, PRODUCT, and DIVID ...
Topics-Ch4Ch5
... Double-click on the join line that connects the tables. Click the bullet next to the join property desired. For example, in the 240students.mdb database, suppose we want all students and the pets they own. All students should be listed regardless of whether they own a pet or not. This is perfect for ...
... Double-click on the join line that connects the tables. Click the bullet next to the join property desired. For example, in the 240students.mdb database, suppose we want all students and the pets they own. All students should be listed regardless of whether they own a pet or not. This is perfect for ...
Lecture 4
... Weak Entity Set ==> Entity Set’s key is composed of attributes of which some or all belong to another Entity Set There are two principal sources of weak entity sets 1) If entities of set E are subunits of entities in F, then it is possible that then names of E entities are not unique until we take i ...
... Weak Entity Set ==> Entity Set’s key is composed of attributes of which some or all belong to another Entity Set There are two principal sources of weak entity sets 1) If entities of set E are subunits of entities in F, then it is possible that then names of E entities are not unique until we take i ...
Distributed Databases - Computer Science, Stony Brook University
... join_cond T2 using a semijoin, first compute T1 join_cond T2 then join it with T2: πattributes(T1)( T1 ...
... join_cond T2 using a semijoin, first compute T1 join_cond T2 then join it with T2: πattributes(T1)( T1 ...
Oracle Demo Database Sample Queries
... The names of your tables and attributes should be unambiguous and meaningful. Have one member of your group hand in the following: - A copy of the Relational Model, - SQL DDL to create your database - Output from DESCRIBE command executed in ORACLE for each of your tables.
...
... The names of your tables and attributes should be unambiguous and meaningful. Have one member of your group hand in the following: - A copy of the Relational Model, - SQL DDL to create your database - Output from DESCRIBE
