1 Structured Query Language 2 DDL
... of birth. There is also the ‘primary key’ definition. A primary key is a column value that uniquely identifies a database record. So for example, we can have two ‘person’ records with the same last name and first name, but with different ids. Besides for primary key, there are many other flags we ca ...
... of birth. There is also the ‘primary key’ definition. A primary key is a column value that uniquely identifies a database record. So for example, we can have two ‘person’ records with the same last name and first name, but with different ids. Besides for primary key, there are many other flags we ca ...
SQL Queries - EECS: www-inst.eecs.berkeley.edu
... • Field values in a tuple are sometimes unknown (e.g., a rating has not been assigned) or inapplicable (e.g., no spouse’s name). – SQL provides a special value null for such situations. • The presence of null complicates many issues. E.g.: – Special operators needed to check if value is/is not null. ...
... • Field values in a tuple are sometimes unknown (e.g., a rating has not been assigned) or inapplicable (e.g., no spouse’s name). – SQL provides a special value null for such situations. • The presence of null complicates many issues. E.g.: – Special operators needed to check if value is/is not null. ...
Modeling and Querying Moving Objects
... query is entered. For example, the query Q = ”Display the motels within 5 miles of my position”, when considered as an instantaneous query returns a set of motels presented to the user immediately after the query is evaluated. Observe that an instantaneous query may refer to the future history, and ...
... query is entered. For example, the query Q = ”Display the motels within 5 miles of my position”, when considered as an instantaneous query returns a set of motels presented to the user immediately after the query is evaluated. Observe that an instantaneous query may refer to the future history, and ...
for Intuitive An Data
... may participate in multiple invoices; the Client and the Invoice tables are linked by the Client Id fields. If a client may have an arbitrary number of addresses or phone numbers, we could build new address or phone number tables and also link them by the Client Id field. Presentation of data across ...
... may participate in multiple invoices; the Client and the Invoice tables are linked by the Client Id fields. If a client may have an arbitrary number of addresses or phone numbers, we could build new address or phone number tables and also link them by the Client Id field. Presentation of data across ...
Pizza Parlor Point-Of-Sales System CMPS 342 Database Systems
... The Customer entity holds basic information about customers when phone orders are placed, whether it is a pick-up or delivery. For a pick-up customers are identified by their name and phone number. For a delivery the address is obviously needed to get the order to the customer. Although no attribute ...
... The Customer entity holds basic information about customers when phone orders are placed, whether it is a pick-up or delivery. For a pick-up customers are identified by their name and phone number. For a delivery the address is obviously needed to get the order to the customer. Although no attribute ...
Lecture27 - The University of Texas at Dallas
... However, a Computer cannot accomplish the same tasks without human direction because web pages are designed to be read by people, not machines. The semantic web is a vision of information that is understandable by computers, so that they can perform more of the tedious work involved in finding, shar ...
... However, a Computer cannot accomplish the same tasks without human direction because web pages are designed to be read by people, not machines. The semantic web is a vision of information that is understandable by computers, so that they can perform more of the tedious work involved in finding, shar ...
host language
... Any boolean-valued condition is appropriate. It is evaluated before or after the triggering event, depending on whether BEFORE or AFTER is used in the event. Access the new/old tuple or set of tuples through the names declared in the REFERENCING clause. ...
... Any boolean-valued condition is appropriate. It is evaluated before or after the triggering event, depending on whether BEFORE or AFTER is used in the event. Access the new/old tuple or set of tuples through the names declared in the REFERENCING clause. ...
CSE 562 Database Systems Example DB Constraints, Triggers, Views, Indexes
... • A major problem in making a database run fast is deciding which indexes to create • Pro: An index speeds up queries that can use it • Con: An index slows down all modifications on its relation because the index must be modified ...
... • A major problem in making a database run fast is deciding which indexes to create • Pro: An index speeds up queries that can use it • Con: An index slows down all modifications on its relation because the index must be modified ...
File
... How to Create tables with SQL • The columns needed for each table can be defined using the CREATE TABLE command. The syntax for this is shown in the upcoming figure. These are the seven steps to follow: • 1. Identify the appropriate datatype for each columns, including length and precision • 2. Ide ...
... How to Create tables with SQL • The columns needed for each table can be defined using the CREATE TABLE command. The syntax for this is shown in the upcoming figure. These are the seven steps to follow: • 1. Identify the appropriate datatype for each columns, including length and precision • 2. Ide ...
Analyzing Performance of Hierarchical Queries in XED
... to check the performance difference for selection at the various syntaxes, we show the classification of the query different levels of hierarchy while fixing the projection at a based on the projection and selection target. single node. The query implementation is dependent on the database type. Suc ...
... to check the performance difference for selection at the various syntaxes, we show the classification of the query different levels of hierarchy while fixing the projection at a based on the projection and selection target. single node. The query implementation is dependent on the database type. Suc ...
Document
... the SQL create table statement: • 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 ...
... the SQL create table statement: • 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 ...
SQL - WISE Research Group
... Note: predicates in the having clause are applied after the formation of groups whereas predicates in the where clause are applied before forming groups ...
... Note: predicates in the having clause are applied after the formation of groups whereas predicates in the where clause are applied before forming groups ...
- Courses - University of California, Berkeley
... be used to build some desired relation from the database. • Relational Calculus provides a notation for formulating the definition of that desired relation in terms of the relations in the database without explicitly stating the operations to be performed • SQL is based on the relational calculus. ...
... be used to build some desired relation from the database. • Relational Calculus provides a notation for formulating the definition of that desired relation in terms of the relations in the database without explicitly stating the operations to be performed • SQL is based on the relational calculus. ...
Chapter 17: Parallel Databases
... Choose processors P0, ..., Pm, where m n -1 to do sorting. Create range-partition vector with m entries, on the sorting attributes Redistribute the relation using range partitioning ...
... Choose processors P0, ..., Pm, where m n -1 to do sorting. Create range-partition vector with m entries, on the sorting attributes Redistribute the relation using range partitioning ...
Chapter 10 Review Questions and Answers
... Click the plus sign to expand the subdatasheet for a record. d) How is a displayed subdatasheet removed from view? A plus sign changes to a minus sign when a subdatasheet is displayed. Click the minus sign to remove the subdatasheet. 11. a) What is a select query? A select query is a database object ...
... Click the plus sign to expand the subdatasheet for a record. d) How is a displayed subdatasheet removed from view? A plus sign changes to a minus sign when a subdatasheet is displayed. Click the minus sign to remove the subdatasheet. 11. a) What is a select query? A select query is a database object ...
Unity_lawrence
... Else take field mapping with best semantic name match Else take first mapping found ...
... Else take field mapping with best semantic name match Else take first mapping found ...
Slides (Powerpoint)
... http://toto.lib.unca.edu/findingaids/photo/national_climatic_data_center/NCDC_interior.htm NOAA's National Climatic Data Center is the source of this image and it is used by permission ...
... http://toto.lib.unca.edu/findingaids/photo/national_climatic_data_center/NCDC_interior.htm NOAA's National Climatic Data Center is the source of this image and it is used by permission ...
Query Optimization In Compressed Database Systems.
... rates by orders of magnitude, enabling the use of data compression techniques to improve the performance of database systems. Previous work describes the benefits of compression for numerical attributes, where data is stored in compressed format on disk. Despite the abundance of stringvalued attribut ...
... rates by orders of magnitude, enabling the use of data compression techniques to improve the performance of database systems. Previous work describes the benefits of compression for numerical attributes, where data is stored in compressed format on disk. Despite the abundance of stringvalued attribut ...