primary key
... Procedures and functions can be invoked also from dynamic SQL SQL:1999 allows more than one function/procedure of the same name (called name overloading), as long as the number of arguments differ, or at least the types of the arguments differ Database Management Systems ...
... Procedures and functions can be invoked also from dynamic SQL SQL:1999 allows more than one function/procedure of the same name (called name overloading), as long as the number of arguments differ, or at least the types of the arguments differ Database Management Systems ...
Query Optimization
... from borrower, t1 where t1.customer-name = borrower.customer-name • The process of replacing a nested query by a query with a join (possibly with a temporary relation) is called decorrelation. • Decorrelation is more complicated when – the nested subquery uses aggregation, or – when the result of th ...
... from borrower, t1 where t1.customer-name = borrower.customer-name • The process of replacing a nested query by a query with a join (possibly with a temporary relation) is called decorrelation. • Decorrelation is more complicated when – the nested subquery uses aggregation, or – when the result of th ...
Chapter 3: Introduction to SQL - Computer Engineering Department
... the operation, +, –, , and /, and operating on constants or attributes of tuples. ...
... the operation, +, –, , and /, and operating on constants or attributes of tuples. ...
ppt - FCN
... Outer Join An extension of the join operation that avoids loss of information. Computes the join and then adds tuples form one relation that does not ...
... Outer Join An extension of the join operation that avoids loss of information. Computes the join and then adds tuples form one relation that does not ...
Distributed Database System
... Different sites may use different schemas and software Difference in schema is a major problem for query processing Difference in software is a major problem for transaction ...
... Different sites may use different schemas and software Difference in schema is a major problem for query processing Difference in software is a major problem for transaction ...
Object-Oriented Databases Need for Complex Data Types
... ■ But many systems insist an object should have a most-specific ...
... ■ But many systems insist an object should have a most-specific ...
Chapter 14: Query Optimization
... Two expressions in the multiset version of the relational algebra given a SQL query are said to be equivalent if on every legal database instance the two expressions generate the same multiset of tuples ...
... Two expressions in the multiset version of the relational algebra given a SQL query are said to be equivalent if on every legal database instance the two expressions generate the same multiset of tuples ...
Probabilistic Databases: Diamonds in the Dirt (Extended Version)
... prepared to deal with it. In contrast, these newly emerging applications offer value precisely because they query, search, and aggregate large volumes of imprecise data to find the “diamonds in the dirt”. This wide-variety of applications points to the need for generic tools to manage imprecise data ...
... prepared to deal with it. In contrast, these newly emerging applications offer value precisely because they query, search, and aggregate large volumes of imprecise data to find the “diamonds in the dirt”. This wide-variety of applications points to the need for generic tools to manage imprecise data ...
Additional Topics
... interface (SQL) and the programming language Alternatively, bindings between variables in SQL statements and variables in the programming language ...
... interface (SQL) and the programming language Alternatively, bindings between variables in SQL statements and variables in the programming language ...
- bYTEBoss
... It is good to have BCNF relation schemas. If a relation schema is not in BCNF, then decompose it into a set of relation schemas: every new schema is in BCNF; it is lossless-join (can guarantee); it is dependency-preserving (no guarantee). If not possible to have all nice properties, be happ ...
... It is good to have BCNF relation schemas. If a relation schema is not in BCNF, then decompose it into a set of relation schemas: every new schema is in BCNF; it is lossless-join (can guarantee); it is dependency-preserving (no guarantee). If not possible to have all nice properties, be happ ...
notes - Course Website Directory
... 1. If we declare that an attribute A is UNIQUE, we cannot have two tuples where the attribute A has a NULL value. 2. Insertion in SQL supports the bag semantics. 3. There is no way to define a primary key containing multiple attributes in SQL. 4. If we execute an UPDATE-SET-WHERE statement, every ti ...
... 1. If we declare that an attribute A is UNIQUE, we cannot have two tuples where the attribute A has a NULL value. 2. Insertion in SQL supports the bag semantics. 3. There is no way to define a primary key containing multiple attributes in SQL. 4. If we execute an UPDATE-SET-WHERE statement, every ti ...
CHAPTER 3 Relational Database Management System: Oracle™
... is a recursive query in which the data tree needs to be traversed from the employee node all the way down to the leaves in the sub-tree. One common strategy to solve this problem is to use a temporary table of social security numbers. Initially, this temporary table will store the next level supervi ...
... is a recursive query in which the data tree needs to be traversed from the employee node all the way down to the leaves in the sub-tree. One common strategy to solve this problem is to use a temporary table of social security numbers. Initially, this temporary table will store the next level supervi ...
Example - Intranet DCC
... This can be sended using the methods: executeUpdate(String), used to create/modify tables (there is no results), commonly used for the create,update,delete sentences. executeQuery(String) to make queries, returns results in an object from the class ResulSet, tipically for a select statement. ...
... This can be sended using the methods: executeUpdate(String), used to create/modify tables (there is no results), commonly used for the create,update,delete sentences. executeQuery(String) to make queries, returns results in an object from the class ResulSet, tipically for a select statement. ...
Incremental Maintenance of Views with Duplicates
... Duplicates cannot be removed from the projection since the result would be wrong when at least two employees had the same salary. Not eliminating duplicates also speeds up query evaluation, as duplicate elimination is generally a rather expensive operation. Many theoretical results obtained for set- ...
... Duplicates cannot be removed from the projection since the result would be wrong when at least two employees had the same salary. Not eliminating duplicates also speeds up query evaluation, as duplicate elimination is generally a rather expensive operation. Many theoretical results obtained for set- ...
Horn Clauses and Database Dependencies
... now we assume that we are dealing with only a single relation at a time.) We assume that we are given a set of individual variables (which represent entries in a relation). Assume that P represents a d-ary relation. Then the atomic formulas are those that are either of the form Pz~ . . . zd (where t ...
... now we assume that we are dealing with only a single relation at a time.) We assume that we are given a set of individual variables (which represent entries in a relation). Assume that P represents a d-ary relation. Then the atomic formulas are those that are either of the form Pz~ . . . zd (where t ...
name varchar
... select title, author, Publisher (pub_name, pub_branch ) as publisher, collect (keyword) as keyword_set from flat-books group by title, author, publisher // See fig 9.4 in the textbook To nest on both authors and keywords: select title, collect (author ) as author_set, Publisher (pub_name, pub_branch ...
... select title, author, Publisher (pub_name, pub_branch ) as publisher, collect (keyword) as keyword_set from flat-books group by title, author, publisher // See fig 9.4 in the textbook To nest on both authors and keywords: select title, collect (author ) as author_set, Publisher (pub_name, pub_branch ...
4. Intermediate SQL
... ©Silberschatz, Korth and Sudarshan See www.db-book.com for conditions on re-use ...
... ©Silberschatz, Korth and Sudarshan See www.db-book.com for conditions on re-use ...
Knowledge Discovery in Databases An Inductive Logic
... valid regardless of whether or not jane is a customer. If we regard the attribute value yes of customer as the classi cation of positive examples and the value no as the classi cation of negative examples, then we can apply concept learning on customer yes. Not knowing whether jane is a customer doe ...
... valid regardless of whether or not jane is a customer. If we regard the attribute value yes of customer as the classi cation of positive examples and the value no as the classi cation of negative examples, then we can apply concept learning on customer yes. Not knowing whether jane is a customer doe ...
Normalization of Database Tables
... Conversion to First Normal Form (continued) • Step 1: Eliminate the Repeating Groups – Present data in tabular format, where each cell has single value and there are no repeating groups – Eliminate repeating groups, eliminate nulls by making sure that each repeating group attribute contains an appr ...
... Conversion to First Normal Form (continued) • Step 1: Eliminate the Repeating Groups – Present data in tabular format, where each cell has single value and there are no repeating groups – Eliminate repeating groups, eliminate nulls by making sure that each repeating group attribute contains an appr ...
Types of Queries - Information Technology
... A query is a description of records that are to be retrieved from a database table. It helps answer questions about the information in a database. For example, “Which students received a G.P.A. of 3.0 or higher?” or “Which students are taking an English course?” When creating a query, the names of t ...
... A query is a description of records that are to be retrieved from a database table. It helps answer questions about the information in a database. For example, “Which students received a G.P.A. of 3.0 or higher?” or “Which students are taking an English course?” When creating a query, the names of t ...