E-R Modeling - CSCI 6442
... say “it’s to make rows unique” or “to provide a unique identifier.” This is terribly wrong! That’s a fine idea for an Excel spreadsheet but it shows a misunderstanding of what a relation is and what a tuple is. Tuples are naturally unique because each one corresponds to a distinct instance of an ent ...
... say “it’s to make rows unique” or “to provide a unique identifier.” This is terribly wrong! That’s a fine idea for an Excel spreadsheet but it shows a misunderstanding of what a relation is and what a tuple is. Tuples are naturally unique because each one corresponds to a distinct instance of an ent ...
IR in P2P, relational data, OpenURL, and full
... aggregators • Proquest and ebsco work as aggregators. They put different scholarly journals in one database together, so you don’t have do deal with publisher’s different interfaces. • Publishers are reluctant to join and impose moving-wall embargos on full-text release. • So you can not access the ...
... aggregators • Proquest and ebsco work as aggregators. They put different scholarly journals in one database together, so you don’t have do deal with publisher’s different interfaces. • Publishers are reluctant to join and impose moving-wall embargos on full-text release. • So you can not access the ...
NoSQL
... Most modern NoSQL systems diverge from the relational model or standard RDBMS functionality: The data model: ...
... Most modern NoSQL systems diverge from the relational model or standard RDBMS functionality: The data model: ...
ad44319 approaches for updating databases wit v
... all with the same key or primary attributes, so that desirable information can be recorded solely by creating tuples without inapplicable[Codd 79, EI-Masri 79, 80, Wiederhold 83]. If the logical database design corresponds in this manner to the objects identified, and we assume that no null values a ...
... all with the same key or primary attributes, so that desirable information can be recorded solely by creating tuples without inapplicable[Codd 79, EI-Masri 79, 80, Wiederhold 83]. If the logical database design corresponds in this manner to the objects identified, and we assume that no null values a ...
SQL Server Notes
... • I’ll meet with your group to setup the DB • You’ll define tables – keys – foreign keys ...
... • I’ll meet with your group to setup the DB • You’ll define tables – keys – foreign keys ...
Nov-28-information-e..
... documents of 135,000 newspaper article database Tuples strategy: Recall at most 46% ...
... documents of 135,000 newspaper article database Tuples strategy: Recall at most 46% ...
slides - UCLA Computer Science
... SQL permits the user to specify where they should occur by using nulls first or nulls last, for instance select student-id, rank ( ) over (order by marks desc nulls last) as s-rank from student-marks ...
... SQL permits the user to specify where they should occur by using nulls first or nulls last, for instance select student-id, rank ( ) over (order by marks desc nulls last) as s-rank from student-marks ...
lection4-relational_database_development
... provide a tree-like hierarchy with the exception that child tables were allowed to have more than one parent. This allowed the network model to support many-to-many relationships. Problem. This model was difficult to ...
... provide a tree-like hierarchy with the exception that child tables were allowed to have more than one parent. This allowed the network model to support many-to-many relationships. Problem. This model was difficult to ...
Fundamentals of Database Systems
... Constraints on a Single Table I We may add constraints such as uniqueness constraints, primary keys and foreign keys to a table definition extending the CREATE TABLE statement I NOT NULL constraints can be attached to an attribute I disallow any occurrences of the null maker on that attribute I a ta ...
... Constraints on a Single Table I We may add constraints such as uniqueness constraints, primary keys and foreign keys to a table definition extending the CREATE TABLE statement I NOT NULL constraints can be attached to an attribute I disallow any occurrences of the null maker on that attribute I a ta ...
Query Processing & Optimization
... Using Heuristics in Query Optimization (15) Outline of a Heuristic Algebraic Optimization Algorithm: 1. Using rule 1, break up any select operations with conjunctive conditions into a cascade of select ops. 2. Using rules 2, 4, 6, and 10 concerning the commutativity of select with other operations, ...
... Using Heuristics in Query Optimization (15) Outline of a Heuristic Algebraic Optimization Algorithm: 1. Using rule 1, break up any select operations with conjunctive conditions into a cascade of select ops. 2. Using rules 2, 4, 6, and 10 concerning the commutativity of select with other operations, ...
Physical Data Modelling
... What are the Names, Jobs and Hours worked by those in the Sales Dept? PROJECT ( SELECT ( JOIN Employee AND Assignment OVER EmpNo) ...
... What are the Names, Jobs and Hours worked by those in the Sales Dept? PROJECT ( SELECT ( JOIN Employee AND Assignment OVER EmpNo) ...
AdvancedQueries
... COUNT(*) handles NULLs like other values, I.e., they are counted All other aggregate operations simply discard NULL values ...
... COUNT(*) handles NULLs like other values, I.e., they are counted All other aggregate operations simply discard NULL values ...
Active Data Objects in .Net
... – Use Connection object and Command to connect a DataReader object to database and read iteratively. – Use Connection object and Command to connect a DataReader and execute an SQL statement or stored procedure. ...
... – Use Connection object and Command to connect a DataReader object to database and read iteratively. – Use Connection object and Command to connect a DataReader and execute an SQL statement or stored procedure. ...
A Multistrategy Approach to Relational Knowledge Discovery in
... The size of tim hypothesis space determines the cost of hypothesis generation. For each hypothesis, two SQL statements have to be executed by the database system. These determine the cost of hypothesis testing. Here, the size of the hypothesis space is described in terms of the representation RDT/DB ...
... The size of tim hypothesis space determines the cost of hypothesis generation. For each hypothesis, two SQL statements have to be executed by the database system. These determine the cost of hypothesis testing. Here, the size of the hypothesis space is described in terms of the representation RDT/DB ...
IR in P2P, relational data, OpenURL and full
... • The idea of network news was born in 1979 when two graduate students, Tom Truscott and Jim Ellis, thought of using UUCP to connect machines for the purpose of information exchange among users. They set up a small network of three machines in North Carolina. • UUCP is ``UNIX to UNIX copy'' a protoc ...
... • The idea of network news was born in 1979 when two graduate students, Tom Truscott and Jim Ellis, thought of using UUCP to connect machines for the purpose of information exchange among users. They set up a small network of three machines in North Carolina. • UUCP is ``UNIX to UNIX copy'' a protoc ...
ppt slides
... in the database that, if joined, might contain rows having all keywords. The resulting relation will contain all potential rows having all keywords specified in the query. If we view the schema graph G as an undirected graph, this step enumerates join trees, i.e., subtrees of G such that: (a) the le ...
... in the database that, if joined, might contain rows having all keywords. The resulting relation will contain all potential rows having all keywords specified in the query. If we view the schema graph G as an undirected graph, this step enumerates join trees, i.e., subtrees of G such that: (a) the le ...