A Conceptual Model and Predicate Language for Data Selection
... confirmed or doubted, by whom, when, and in what order. The model provides distinct provenance at multiple granularities, including relations, tuples, schema attributes, and attribute values. Our provenance model also supports multiple histories for data, because for example in settings we address, ...
... confirmed or doubted, by whom, when, and in what order. The model provides distinct provenance at multiple granularities, including relations, tuples, schema attributes, and attribute values. Our provenance model also supports multiple histories for data, because for example in settings we address, ...
The Relational Database Model
... A database can be understood as a collection of related files. How those files are related depends on the model used. Early models included the hierarchical model (where files are related in a parent/child manner, with each child file having at most one parent file), and the network model (where fil ...
... A database can be understood as a collection of related files. How those files are related depends on the model used. Early models included the hierarchical model (where files are related in a parent/child manner, with each child file having at most one parent file), and the network model (where fil ...
Chapter 4
... • SQL has directly incorporated some set operations • The set operations are: union (UNION), set difference (EXCEPT or MINUS) and intersection (INTERSECT) • Results of these set operations are sets of tuples; duplicate tuples are eliminated from the result • Set operations apply only to type compati ...
... • SQL has directly incorporated some set operations • The set operations are: union (UNION), set difference (EXCEPT or MINUS) and intersection (INTERSECT) • Results of these set operations are sets of tuples; duplicate tuples are eliminated from the result • Set operations apply only to type compati ...
Introduction
... are specified in a DBMS Physical layer – how things and their relationships are stored in physical space, e.g. disks The separation of these three layers allow the change of one or more layers without affecting the other layers ...
... are specified in a DBMS Physical layer – how things and their relationships are stored in physical space, e.g. disks The separation of these three layers allow the change of one or more layers without affecting the other layers ...
Poor Naming Standards
... Rule #4: Prefixes- Do not prefix your fields with "fld_" or "Col_" as it should be obvious in SQL statements which items are columns (before or after the FROM clause). Including a two or three character data type prefix for the field is optional and not recommended, Example: "IntCustomerId" for a nu ...
... Rule #4: Prefixes- Do not prefix your fields with "fld_" or "Col_" as it should be obvious in SQL statements which items are columns (before or after the FROM clause). Including a two or three character data type prefix for the field is optional and not recommended, Example: "IntCustomerId" for a nu ...
Select - DidaWiki
... foreach (Person p in persons) Console.WriteLine(“{0} {1}”, p.FirstName, p.LastName); ...
... foreach (Person p in persons) Console.WriteLine(“{0} {1}”, p.FirstName, p.LastName); ...
create table - NCNU Moodle 課程
... Summary • Structured Query Language (SQL) is a language that is used to manipulate relational databases • Basic form of an SQL query: SELECT-FROMWHERE • Use CREATE TABLE command to describe table layout to the DBMS, which creates the table • In SQL retrieval commands, fields are listed after SELECT ...
... Summary • Structured Query Language (SQL) is a language that is used to manipulate relational databases • Basic form of an SQL query: SELECT-FROMWHERE • Use CREATE TABLE command to describe table layout to the DBMS, which creates the table • In SQL retrieval commands, fields are listed after SELECT ...
The Relational Model
... information (or a summary), while hiding details in underlying relation(s). ...
... information (or a summary), while hiding details in underlying relation(s). ...
Chapter 3
... Summary • Structured Query Language (SQL) is a language that is used to manipulate relational databases • Basic form of an SQL query: SELECT-FROMWHERE • Use CREATE TABLE command to describe table layout to the DBMS, which creates the table • In SQL retrieval commands, fields are listed after SELECT ...
... Summary • Structured Query Language (SQL) is a language that is used to manipulate relational databases • Basic form of an SQL query: SELECT-FROMWHERE • Use CREATE TABLE command to describe table layout to the DBMS, which creates the table • In SQL retrieval commands, fields are listed after SELECT ...
CS211 Lecture: Database Design last revised November 21, 2006 Objectives:
... containing a student_id that does not appear in Student. F. Nulls 1. One interesting question that arises in database design is how are we to handle a situation where we don't have values available for all the attributes of an entity. We have already seen that relational DBMS's provide a special val ...
... containing a student_id that does not appear in Student. F. Nulls 1. One interesting question that arises in database design is how are we to handle a situation where we don't have values available for all the attributes of an entity. We have already seen that relational DBMS's provide a special val ...
slides
... The subset of R2 is a foreign key referencing K1 in relation r1, if for every t2 in r2 there must be a tuple t1 in r1 such that t1[K1] = t2[]. Referential integrity constraint also called subset dependency since its ...
... The subset of R2 is a foreign key referencing K1 in relation r1, if for every t2 in r2 there must be a tuple t1 in r1 such that t1[K1] = t2[]. Referential integrity constraint also called subset dependency since its ...
The Relational Data Model
... There are no “positional concepts”: In other words, the columns can be viewed in any order without affecting the meaning of the data. ...
... There are no “positional concepts”: In other words, the columns can be viewed in any order without affecting the meaning of the data. ...
No Slide Title
... A relation in the database A constant relation (e.g., {(A-101,Downtown,500)}) Let E1 and E2 be relational-algebra expressions; the following are ...
... A relation in the database A constant relation (e.g., {(A-101,Downtown,500)}) Let E1 and E2 be relational-algebra expressions; the following are ...
Parallel Databases - UCF Computer Science
... { Advantage: requires only one hash table. { Disadvantage: pipelining along the outer relation must be suspended during the build phase (i.e., building the hash table). ...
... { Advantage: requires only one hash table. { Disadvantage: pipelining along the outer relation must be suspended during the build phase (i.e., building the hash table). ...
normalization - SJSU Engineering
... The aim of normalization is to remove certain kinds of data redundancy, and therefore avoid update anomalies. Update anomalies are difficulties with the insert, update and delete operations on a database due to the data structure. FIRST NORMAL FORM (1NF) An entity is said to be in first normal form ...
... The aim of normalization is to remove certain kinds of data redundancy, and therefore avoid update anomalies. Update anomalies are difficulties with the insert, update and delete operations on a database due to the data structure. FIRST NORMAL FORM (1NF) An entity is said to be in first normal form ...
Dynamic Inference Control
... As part of the agent design, each agent will be given an attribute directory that species which databases contain which attributes. The contents of this directory will be specified at rule generation time. ...
... As part of the agent design, each agent will be given an attribute directory that species which databases contain which attributes. The contents of this directory will be specified at rule generation time. ...
document
... Aggregate queries can also display subtotal information by creating groups of rows that have data in common ◦ An example would be a query that displays the average price of a book for each publisher ◦ Use the GROUP BY clause SELECT PublisherID, Avg(Price) As AvgPrice FROM Book GROUP BY PublisherID ...
... Aggregate queries can also display subtotal information by creating groups of rows that have data in common ◦ An example would be a query that displays the average price of a book for each publisher ◦ Use the GROUP BY clause SELECT PublisherID, Avg(Price) As AvgPrice FROM Book GROUP BY PublisherID ...
integrity-security
... The primary key clause lists attributes that comprise the primary key. The unique key clause lists attributes that comprise a candidate key. The foreign key clause lists the attributes that comprise the foreign key and the name of the relation referenced by the foreign key. ...
... The primary key clause lists attributes that comprise the primary key. The unique key clause lists attributes that comprise a candidate key. The foreign key clause lists the attributes that comprise the foreign key and the name of the relation referenced by the foreign key. ...
Subqueries and Joining
... MovieInformation database, we get a result with 49 rows… • 49 = 7 x 7. All combinations of Movie records (7) and Actor records (7) • All fields from both tables are included • This is rarely what we want… SWC – 2011 ...
... MovieInformation database, we get a result with 49 rows… • 49 = 7 x 7. All combinations of Movie records (7) and Actor records (7) • All fields from both tables are included • This is rarely what we want… SWC – 2011 ...
Lecture 6
... should see a relation described, in SQL, by (select customer_name, borrower.loan_number, branch_name from borrower, loan where borrower.loan_number = loan.loan_number ) ■ A view provides a mechanism to hide certain data from the view of ...
... should see a relation described, in SQL, by (select customer_name, borrower.loan_number, branch_name from borrower, loan where borrower.loan_number = loan.loan_number ) ■ A view provides a mechanism to hide certain data from the view of ...
AUCSC 330 - Database Management Systems I
... students within the course. Normally this shift will benefit students. Academic Integrity: The University of Alberta is committed to the highest standards of academic integrity and honesty. Students are expected to be familiar with these standards regarding academic honesty and to uphold the policie ...
... students within the course. Normally this shift will benefit students. Academic Integrity: The University of Alberta is committed to the highest standards of academic integrity and honesty. Students are expected to be familiar with these standards regarding academic honesty and to uphold the policie ...
chapter02
... can include calculated fields that are not in the database in queries field (calculated field) – a field that is the result of a calculation using one or more ...
... can include calculated fields that are not in the database in queries field (calculated field) – a field that is the result of a calculation using one or more ...