ISY 321 - Systems Analysis Methods
... considered group effort. All involved in group effort homework will receive a zero grade for that assignment. A student turning in a group effort assignment more than once will automatically receive an “F” grade for the course. Late Assignment: All lab assignments are due at the beginning of class o ...
... considered group effort. All involved in group effort homework will receive a zero grade for that assignment. A student turning in a group effort assignment more than once will automatically receive an “F” grade for the course. Late Assignment: All lab assignments are due at the beginning of class o ...
SUPP PART-NO
... – Concern that a large number of tables-and table joins-will result in poor performance • Join can be a very expensive operation • Test to determine frequency of joins, number of tables joined –After database is created and available ...
... – Concern that a large number of tables-and table joins-will result in poor performance • Join can be a very expensive operation • Test to determine frequency of joins, number of tables joined –After database is created and available ...
Slides - CIS @ Temple University
... else for each non-empty subset S1 of S such that S1 S P1= findbestplan(S1) P2= findbestplan(S - S1) A = best algorithm for joining results of P1 and P2 cost = P1.cost + P2.cost + cost of A if cost < bestplan[S].cost bestplan[S].cost = cost bestplan[S].plan = “execute P1.plan; execute P2.plan; join ...
... else for each non-empty subset S1 of S such that S1 S P1= findbestplan(S1) P2= findbestplan(S - S1) A = best algorithm for joining results of P1 and P2 cost = P1.cost + P2.cost + cost of A if cost < bestplan[S].cost bestplan[S].cost = cost bestplan[S].plan = “execute P1.plan; execute P2.plan; join ...
Topic: The Relational Database Model and Database Development
... Candidate Key The smallest number of attributes required to uniquely identify each row in a table. For example, in an employee table the name, address, and home phone could be a super key, but the employee social-security number would be a candidate key, because it’s minimal. In practice, singleat ...
... Candidate Key The smallest number of attributes required to uniquely identify each row in a table. For example, in an employee table the name, address, and home phone could be a super key, but the employee social-security number would be a candidate key, because it’s minimal. In practice, singleat ...
Document
... relations, with on delete cascade specified for each dependency a deletion or update at one end of the chain can propagate across the entire chain. If a cascading update or delete causes a constraint violation that ...
... relations, with on delete cascade specified for each dependency a deletion or update at one end of the chain can propagate across the entire chain. If a cascading update or delete causes a constraint violation that ...
here
... a join in which the joining condition is based on equality between values in the common columns; common columns appear redundantly in the result table an equi-join in which one of the duplicate columns is eliminated in the result table ...
... a join in which the joining condition is based on equality between values in the common columns; common columns appear redundantly in the result table an equi-join in which one of the duplicate columns is eliminated in the result table ...
Introduction to Database Management
... database • To query a database is to question it (ask a question) • Query a database to pull out specific information ...
... database • To query a database is to question it (ask a question) • Query a database to pull out specific information ...
A METHOD FOR MINING FUNCTIONAL DEPENDENCIES IN
... some significant tuples. It is not necessary to use all the rows of a database table, but it is important to select varied tuples, with different styles of data, in order to get as many conclusions as possible. Using definitions 3, 4, 5 we construct the formal context of functional dependencies to f ...
... some significant tuples. It is not necessary to use all the rows of a database table, but it is important to select varied tuples, with different styles of data, in order to get as many conclusions as possible. Using definitions 3, 4, 5 we construct the formal context of functional dependencies to f ...
Constraints of binary relationship sets u 1:1-relationship (one-to
... − good performance for standard database applications − existence of a mature, formal theory (in contrast to other data models), in particular with respect to the design of relational databases and with respect to an efficient processing of user queries ...
... − good performance for standard database applications − existence of a mature, formal theory (in contrast to other data models), in particular with respect to the design of relational databases and with respect to an efficient processing of user queries ...
SQL
... Specifying Constraints in SQL Basic Retrieval Queries in SQL INSERT, DELETE, and UPDATE Statements in SQL Additional Features of SQL ...
... Specifying Constraints in SQL Basic Retrieval Queries in SQL INSERT, DELETE, and UPDATE Statements in SQL Additional Features of SQL ...
Slide 6
... Specifying Constraints in SQL Basic Retrieval Queries in SQL INSERT, DELETE, and UPDATE Statements in SQL Additional Features of SQL ...
... Specifying Constraints in SQL Basic Retrieval Queries in SQL INSERT, DELETE, and UPDATE Statements in SQL Additional Features of SQL ...
Normalization
... DKNF requires that each key uniquely identifies each row in a table. A domain is the set of permissible values for an attribute. By enforcing key and domain restrictions, the database is assured of being freed from modification anomalies. ...
... DKNF requires that each key uniquely identifies each row in a table. A domain is the set of permissible values for an attribute. By enforcing key and domain restrictions, the database is assured of being freed from modification anomalies. ...
original
... SQL allows a subquery expression to be used in the from clause Find the average account balance of those branches where the average account balance is greater than $1200. select branch_name, avg_balance from (select branch_name, avg (balance) from account group by branch_name ) ...
... SQL allows a subquery expression to be used in the from clause Find the average account balance of those branches where the average account balance is greater than $1200. select branch_name, avg_balance from (select branch_name, avg (balance) from account group by branch_name ) ...
Ch3
... • Ordering of attributes in a relation schema R (and of values within each tuple): – We will consider the attributes in R(A1, A2, ..., An) and the values in each t= to be ordered
– However, a more general definition of relation (which we will
not use) does not require attribute orde ...
... • Ordering of attributes in a relation schema R (and of values within each tuple): – We will consider the attributes in R(A1, A2, ..., An) and the values in each t=
Topic: The Relational Database Model and Database Development
... Candidate Key The smallest number of attributes required to uniquely identify each row in a table. For example, in an employee table the name, address, and home phone could be a super key, but the employee social-security number would be a candidate key, because it’s minimal. In practice, singleat ...
... Candidate Key The smallest number of attributes required to uniquely identify each row in a table. For example, in an employee table the name, address, and home phone could be a super key, but the employee social-security number would be a candidate key, because it’s minimal. In practice, singleat ...
Comparing M2M Performance
... Improvements with separating numeric values Attributes “can” be in facts instead of dimensions We need to promote into columns to slice on attribute Leaving as measures is more flexible version wise ...
... Improvements with separating numeric values Attributes “can” be in facts instead of dimensions We need to promote into columns to slice on attribute Leaving as measures is more flexible version wise ...
Chapter # 7 (Introduction to Structured Query Language
... Create view by using CREATE VIEW command Special characteristics of relational view: Name of view can be used anywhere a table name is expected View dynamically updated Restricts users to only specified columns and rows Views may be used as basis for reports ...
... Create view by using CREATE VIEW command Special characteristics of relational view: Name of view can be used anywhere a table name is expected View dynamically updated Restricts users to only specified columns and rows Views may be used as basis for reports ...
MIE253 - Lab 6 Relational Algebra and SQL
... questions below. For each, give the SQL and Relational Algebra expressions. It is recommended that you debug your SQL query by comparing and validating the expected query result (by examining the tuples in the database). Additionally, you are occasionally asked to add tuples to the database to satis ...
... questions below. For each, give the SQL and Relational Algebra expressions. It is recommended that you debug your SQL query by comparing and validating the expected query result (by examining the tuples in the database). Additionally, you are occasionally asked to add tuples to the database to satis ...
Algebra
... Selection ( ) Selects a subset of rows from relation. Projection ( ) 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. 1 and in reln. 2. Intersection, join, division, r ...
... Selection ( ) Selects a subset of rows from relation. Projection ( ) 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. 1 and in reln. 2. Intersection, join, division, r ...
What is a Database System?
... a prescription for a way of representing data manipulating data representing integrity constraints ...
... a prescription for a way of representing data manipulating data representing integrity constraints ...