Semantic Data Control
... key columns preserved through a SQL join) and one base table tuple appears at most once in the view. Oracle: select table name, column name, updatable, ...
... key columns preserved through a SQL join) and one base table tuple appears at most once in the view. Oracle: select table name, column name, updatable, ...
6-Query_Intro
... produce ASG': (10+10) tuple access cost transfer ASG' to the sites of EMP: (10+10) tuple transfer cost produce EMP': (10+10) tuple access cost 2 transfer EMP' to result site: (10+10) tuple transfer cost ...
... produce ASG': (10+10) tuple access cost transfer ASG' to the sites of EMP: (10+10) tuple transfer cost produce EMP': (10+10) tuple access cost 2 transfer EMP' to result site: (10+10) tuple transfer cost ...
databases - RealTechSupport
... constructed carefully in order to be useful, so must a database on a computer. Similarly, just as there are many ways that a printed catalog can be organized, there are many ways, or models, by which a computerized database may be organized. One of the most common and powerful models is the `relatio ...
... constructed carefully in order to be useful, so must a database on a computer. Similarly, just as there are many ways that a printed catalog can be organized, there are many ways, or models, by which a computerized database may be organized. One of the most common and powerful models is the `relatio ...
Lecture 1 - Salim Arfaoui
... • Each relational database table stores data about a particular entity (a person, place, thing, or event). • In the example below, there are 3 repair orders for Debbie Davies. • However, we don’t store her information (name, address, etc.) more than once. The foreign key value #4 links Debbie Davies ...
... • Each relational database table stores data about a particular entity (a person, place, thing, or event). • In the example below, there are 3 repair orders for Debbie Davies. • However, we don’t store her information (name, address, etc.) more than once. The foreign key value #4 links Debbie Davies ...
Logic: Basic Defintions
... • Recall that the Cartesian product of sets A={a,b,c} and B={d,e} is the set of all pairs of something from A and something from B: A x B = {(a,d),(b,d),(c,d),(a,e),(b,e),(c,e)} • A join of two tables A and B generates a new table whose rows are from the Cartesian product of A and B – So if table A ...
... • Recall that the Cartesian product of sets A={a,b,c} and B={d,e} is the set of all pairs of something from A and something from B: A x B = {(a,d),(b,d),(c,d),(a,e),(b,e),(c,e)} • A join of two tables A and B generates a new table whose rows are from the Cartesian product of A and B – So if table A ...
投影片 1
... the transaction time histories of relational databases can be stored and queried efficiently by using XML and SQL/XML. the query mapping, indexing, clustering, and compression techniques used to achieve performance levels well above those of a native XML DBMS. The approach of ArchIS can be used ...
... the transaction time histories of relational databases can be stored and queried efficiently by using XML and SQL/XML. the query mapping, indexing, clustering, and compression techniques used to achieve performance levels well above those of a native XML DBMS. The approach of ArchIS can be used ...
slides
... Indexing low cardinality attributes • Suppose there are only 4 different years in our previous example. • Then we may represent the locations of N fact table tuples using only 2N bits. • However, an (unclustered) index on location seems to require at least N log N bits. • Can we get by reading ...
... Indexing low cardinality attributes • Suppose there are only 4 different years in our previous example. • Then we may represent the locations of N fact table tuples using only 2N bits. • However, an (unclustered) index on location seems to require at least N log N bits. • Can we get by reading ...
SQL_Saturday_#527_
... Database Join Operation Hash When large, unsorted, non-indexed columns are used in the join condition Engine prepares a hash table for the smaller relation by applying a hash function to the join attribute of each row (sort of like creating a temporary index on the fly) Scans the larger rel ...
... Database Join Operation Hash When large, unsorted, non-indexed columns are used in the join condition Engine prepares a hash table for the smaller relation by applying a hash function to the join attribute of each row (sort of like creating a temporary index on the fly) Scans the larger rel ...
Views
... answer to a view over the virtual schema: UW database: SELECT number, title, prof FROM Course WHERE univ=‘UW’ AND quarter=‘2/02’ Stanford database: SELECT number, title, prof, quarter FROM Course WHERE univ=‘Stanford’ User query: find all professors who teach “database systems” ...
... answer to a view over the virtual schema: UW database: SELECT number, title, prof FROM Course WHERE univ=‘UW’ AND quarter=‘2/02’ Stanford database: SELECT number, title, prof, quarter FROM Course WHERE univ=‘Stanford’ User query: find all professors who teach “database systems” ...
Introduction to Oracle - UWEC Computer Science Department
... UniversityStudent StudentID Student LastName ...
... UniversityStudent StudentID Student LastName ...
Martin
... Static analysis: select candidate queries from the query log Audit query generation: augment every candidate query with information from the audit expression and combine them into an audit query that unions their output ...
... Static analysis: select candidate queries from the query log Audit query generation: augment every candidate query with information from the audit expression and combine them into an audit query that unions their output ...
Physical Database Design
... Suppose that contracts with value > 10000 are subject to different rules. This means that queries on Contracts will often contain the condition val>10000. One way to deal with this is to build a clustered B+ tree index on the val field of Contracts. A second approach is to replace contracts by two n ...
... Suppose that contracts with value > 10000 are subject to different rules. This means that queries on Contracts will often contain the condition val>10000. One way to deal with this is to build a clustered B+ tree index on the val field of Contracts. A second approach is to replace contracts by two n ...
Critique of Relational Database Models
... The agenda for reading Why Relational? Where is Date coming from? what is his bias? How do we classify Date's perceived virtues of relational models? Some virtues differ in nature from others ... ...
... The agenda for reading Why Relational? Where is Date coming from? what is his bias? How do we classify Date's perceived virtues of relational models? Some virtues differ in nature from others ... ...
Lecture 2
... – One row for each list of entities, one from each set, that are connected by the relationship ...
... – One row for each list of entities, one from each set, that are connected by the relationship ...
7. Decision Trees and Decision Rules
... this study, we consider two cases namely, invariance to translationrotation and invariance to translation, rotation, and scale. Prior to computing the attributes, the intersection point between the two lines are computed as shown by “i”. The end point of the first line also known as the reference l ...
... this study, we consider two cases namely, invariance to translationrotation and invariance to translation, rotation, and scale. Prior to computing the attributes, the intersection point between the two lines are computed as shown by “i”. The end point of the first line also known as the reference l ...
Customer
... – For each sales rep with fewer than four customers, list the rep number, the number of customers assigned to the rep, and the average balance of the rep’s customers. Rename the count of the number of customers and the average of the balances to NumOfCustomers and AverageBalance. – Use of “Having” c ...
... – For each sales rep with fewer than four customers, list the rep number, the number of customers assigned to the rep, and the average balance of the rep’s customers. Rename the count of the number of customers and the average of the balances to NumOfCustomers and AverageBalance. – Use of “Having” c ...
Achievements and Weaknesses of Object
... class A is class B, the fetching of the OIDs of objects in a class that are stored as values of an attribute in another class eliminate the need for an implicit join between objects. Therefore, in OODBs there is a distinction between the implicit join, derived from the hierarchical nesting of object ...
... class A is class B, the fetching of the OIDs of objects in a class that are stored as values of an attribute in another class eliminate the need for an implicit join between objects. Therefore, in OODBs there is a distinction between the implicit join, derived from the hierarchical nesting of object ...
IBM Research Report
... operators are closed and can be freely reordered. This free composition allows a user to form larger queries, thereby replacing the relatively inecient one-operation-at-a-time approach of many existing products. The algebraic nature of the cube also provides an opportunity for optimizing multidimen ...
... operators are closed and can be freely reordered. This free composition allows a user to form larger queries, thereby replacing the relatively inecient one-operation-at-a-time approach of many existing products. The algebraic nature of the cube also provides an opportunity for optimizing multidimen ...
Referential Integrity Quality Metrics
... This QM is a measure of consistency. Notice the metric for a foreign attribute is strict in the sense that in order to consider a reference a correct one, not only must its foreign key exist, but also have the same value and such value must be different from null. A comparison between two values in ...
... This QM is a measure of consistency. Notice the metric for a foreign attribute is strict in the sense that in order to consider a reference a correct one, not only must its foreign key exist, but also have the same value and such value must be different from null. A comparison between two values in ...
SQL_Saturday_#521_
... Database Join Operation Hash When large, unsorted, non-indexed columns are used in the join condition Engine prepares a hash table for the smaller relation by applying a hash function to the join attribute of each row (sort of like creating a temporary index on the fly) Scans the larger rel ...
... Database Join Operation Hash When large, unsorted, non-indexed columns are used in the join condition Engine prepares a hash table for the smaller relation by applying a hash function to the join attribute of each row (sort of like creating a temporary index on the fly) Scans the larger rel ...
Computing Consistent Query Answers using Conflict
... is a function that assigns a finite set of tuples to each relation name. For the purposes of this paper we consider only two fixed database domains N (natural numbers) and D (uninterpreted constants). We also use the natural interpretation over N of binary relational symbols =, 6=, <, >, and we assu ...
... is a function that assigns a finite set of tuples to each relation name. For the purposes of this paper we consider only two fixed database domains N (natural numbers) and D (uninterpreted constants). We also use the natural interpretation over N of binary relational symbols =, 6=, <, >, and we assu ...