intro
... of theoretical ideas. “Big 3” DBMS companies are among the largest software companies in the world. IBM (with DB2) and Microsoft (SQL Server, Microsoft Access) are also ...
... of theoretical ideas. “Big 3” DBMS companies are among the largest software companies in the world. IBM (with DB2) and Microsoft (SQL Server, Microsoft Access) are also ...
Review for Final Exam
... where customer-name not in ("Smith", "Jones) Nested Queries: Subqueries can appear in the from, where and having clauses. Find all customers who have both an account and a loan at the bank. select distinct customer-name from Borrower where customer-name in (select customer-name from Depositor) Examp ...
... where customer-name not in ("Smith", "Jones) Nested Queries: Subqueries can appear in the from, where and having clauses. Find all customers who have both an account and a loan at the bank. select distinct customer-name from Borrower where customer-name in (select customer-name from Depositor) Examp ...
28SpCS157BL14TRC4NFASRppt
... • In EQUIJOIN operation, if the two attributes in the join condition have the same name, then in the resulting relation we will have two identical columns. In order to avoid this problem, we define the NATURAL JOIN operation • The NATURAL JOIN operation is denoted by: R3 = R1 * R2
• ...
... • In EQUIJOIN operation, if the two attributes in the join condition have the same name, then in the resulting relation we will have two identical columns. In order to avoid this problem, we define the NATURAL JOIN operation • The NATURAL JOIN operation is denoted by: R3 = R1 *
Exam 1
... ______ Normalization also permits nulls to be stored in database tables. ______ A null value is equivalent to zero in the case of a number type attribute. ______ A functional dependency of Y on X is an extension of the mathematics concept that a value in X clearly determines the corresponding value ...
... ______ Normalization also permits nulls to be stored in database tables. ______ A null value is equivalent to zero in the case of a number type attribute. ______ A functional dependency of Y on X is an extension of the mathematics concept that a value in X clearly determines the corresponding value ...
Slides
... At query time we retrieve and multiply the scores of t in the lists Cx1,…,Cxs and in one of Gx1,…,Gxs. This requires only s+1 multiplications and results in a score2 that is proportional to the actual score. Two kinds of efficient access operations are needed: First, given a value x, it should be po ...
... At query time we retrieve and multiply the scores of t in the lists Cx1,…,Cxs and in one of Gx1,…,Gxs. This requires only s+1 multiplications and results in a score2 that is proportional to the actual score. Two kinds of efficient access operations are needed: First, given a value x, it should be po ...
Tuple Relational Calculus Relational model: Relational calculus
... • Tuples T in result have values for (name, tournament, name2) that satisfy the formula • What is the resulting relation? ...
... • Tuples T in result have values for (name, tournament, name2) that satisfy the formula • What is the resulting relation? ...
SQL Tutorial - Computer Science
... An expression can be assigned a name using as Example select FlashlineID as ID from student Note: as is rename clause, also can be used to rename table name select name as myname from student as S ...
... An expression can be assigned a name using as Example select FlashlineID as ID from student Note: as is rename clause, also can be used to rename table name select name as myname from student as S ...
The relational model
... Many commercial systems are not fully relational because they do not support domains and integrity rules Classified as relationally complete ...
... Many commercial systems are not fully relational because they do not support domains and integrity rules Classified as relationally complete ...
The Relational Data Model: Structure
... – Each attribute of a table defines a set of permitted values for that attribute; this set of permitted set is the domain of that attribute. • This definition of a database table originates from the pure mathematical concept of a relation, from which the term “relational data model” originates. – F ...
... – Each attribute of a table defines a set of permitted values for that attribute; this set of permitted set is the domain of that attribute. • This definition of a database table originates from the pure mathematical concept of a relation, from which the term “relational data model” originates. – F ...
124_Summarization
... Method 1: Use algorithm for Index-Based joins We find tuple of R that matches given tuple of S We need not to read entire relation R Method 2: Use algorithm for Block-Based joins Tuples of R & S are divided into blocks Uses enough memory to store blocks in order to reduce the number of d ...
... Method 1: Use algorithm for Index-Based joins We find tuple of R that matches given tuple of S We need not to read entire relation R Method 2: Use algorithm for Block-Based joins Tuples of R & S are divided into blocks Uses enough memory to store blocks in order to reduce the number of d ...
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New Sample Questions for CS 6371 (APL) [added 11/1/08]
... where key = Nat (set of natural numbers) and list = Nat∗ (list of natural numbers). Thus, a collection of tuples is modeled as a function. Each tuple is modeled as a pair, whose first element is the primary key and the second element is a list of remaining elements of the tuple. Note: DO NOT USE YOU ...
... where key = Nat (set of natural numbers) and list = Nat∗ (list of natural numbers). Thus, a collection of tuples is modeled as a function. Each tuple is modeled as a pair, whose first element is the primary key and the second element is a list of remaining elements of the tuple. Note: DO NOT USE YOU ...
XHTML Basics - Informatics: Indiana University
... The relational model was conceived by E.F. Codd of IBM in 1970. The relational model is based on set theory and is composed of relations (also known as tables). ...
... The relational model was conceived by E.F. Codd of IBM in 1970. The relational model is based on set theory and is composed of relations (also known as tables). ...
The Relational Model
... should keep track of all students (their names, Ids, and addresses) and professors (name, Id, department). Do not record the address of professors but keep track of their ages. Maintain records of courses also. Like what classroom is assigned to a course, what is the current enrollment, and which de ...
... should keep track of all students (their names, Ids, and addresses) and professors (name, Id, department). Do not record the address of professors but keep track of their ages. Maintain records of courses also. Like what classroom is assigned to a course, what is the current enrollment, and which de ...
Chapter 5
... • Tuples (rows) - set of data that describe an instance of the entity represented by a relation; like a record in traditional file structure. • Attributes (columns) - items of data that characterize an object, event, or agent; like fields in traditional file structure. ...
... • Tuples (rows) - set of data that describe an instance of the entity represented by a relation; like a record in traditional file structure. • Attributes (columns) - items of data that characterize an object, event, or agent; like fields in traditional file structure. ...
Exam 1
... ______ A functional dependency X→Y is an extension of the mathematics concept that a value in X clearly determines the corresponding value in Y. ______ Functional dependencies can be determined sufficiently by looking at a sample relation. ______ Functional dependencies are reflexive, i.e., if a →b ...
... ______ A functional dependency X→Y is an extension of the mathematics concept that a value in X clearly determines the corresponding value in Y. ______ Functional dependencies can be determined sufficiently by looking at a sample relation. ______ Functional dependencies are reflexive, i.e., if a →b ...
COMP 521 F10 Final Exam Review
... 19 and 20 into the B+-tree shown? • A. The tree will split and gain a level • B. All nodes of the tree will be filled • C. The tree’s structure is unchanged • D. The resulting tree is identical to the original • E. The tree looses a level ...
... 19 and 20 into the B+-tree shown? • A. The tree will split and gain a level • B. All nodes of the tree will be filled • C. The tree’s structure is unchanged • D. The resulting tree is identical to the original • E. The tree looses a level ...
Relational Database - MUET-CRP
... – Selection ( ) Selects a subset of rows from relation. – Projection (π ) Deletes unwanted columns from relation. – Cross-product (x) Allows us to combine two relations. – Set-difference (-) Tuples in reln. 1, but not in reln. 2. – Union (U) Tuples in reln. 1 and in reln. 2. Additional operations: ...
... – Selection ( ) Selects a subset of rows from relation. – Projection (π ) Deletes unwanted columns from relation. – Cross-product (x) Allows us to combine two relations. – Set-difference (-) Tuples in reln. 1, but not in reln. 2. – Union (U) Tuples in reln. 1 and in reln. 2. Additional operations: ...
ppt format
... • equijoin (based upon equality of attributes) • natural join (equijoin plus projection to eliminate duplicated columns) ...
... • equijoin (based upon equality of attributes) • natural join (equijoin plus projection to eliminate duplicated columns) ...
lecture02
... should keep track of all students (their names, Ids, and addresses) and professors (name, Id, department). Do not record the address of professors but keep track of their ages. Maintain records of courses also. Like what classroom is assigned to a course, what is the current enrollment, and which de ...
... should keep track of all students (their names, Ids, and addresses) and professors (name, Id, department). Do not record the address of professors but keep track of their ages. Maintain records of courses also. Like what classroom is assigned to a course, what is the current enrollment, and which de ...
• Stands for “Structured Query Language” • Essentially a “friendlier
... • implicit union of unaffected tuples ...
... • implicit union of unaffected tuples ...
