Physical Database Design
... • Index is usually small, relative to the table –Can be held entirely in memory • The smaller the index value, the more entries per block the more likely the index will be in memory ...
... • Index is usually small, relative to the table –Can be held entirely in memory • The smaller the index value, the more entries per block the more likely the index will be in memory ...
Introduction to Database - San Francisco State University
... File Organization and Access • Sequential file (heap file): Records are organized in sequence in the order in which they are entered. • File access: – Sequential access – Direct access ...
... File Organization and Access • Sequential file (heap file): Records are organized in sequence in the order in which they are entered. • File access: – Sequential access – Direct access ...
Wait-Time Based Oracle Performance Management
... • If you trace one of the “80” sessions, it appears as if you have no locking issues (and spend time trying to tune other items that may not be important) • If you trace one of the “20” sessions, it appears as if you could fix the locking problems and reduce your wait time by ...
... • If you trace one of the “80” sessions, it appears as if you have no locking issues (and spend time trying to tune other items that may not be important) • If you trace one of the “20” sessions, it appears as if you could fix the locking problems and reduce your wait time by ...
Physical pointers
... – Data independence (logical pointers). • Logical and physical design separate. • Add new fields - don’t need to reestablish pointers. • Can change gracefully as organizations evolve. Rest of design not changed when you change or delete 1 table ...
... – Data independence (logical pointers). • Logical and physical design separate. • Add new fields - don’t need to reestablish pointers. • Can change gracefully as organizations evolve. Rest of design not changed when you change or delete 1 table ...
Transaction Processing and Recovery
... What has happened here? The total is too high because B changed values of A while the total was being computed. The solution is to prevent any changes in any A values while the total is being computed. ...
... What has happened here? The total is too high because B changed values of A while the total was being computed. The solution is to prevent any changes in any A values while the total is being computed. ...
Introduction to Database Systems
... Doing it without a DBMS... • Enroll “Mary Johnson” in “CSE444”: Write a C program to do the following: ...
... Doing it without a DBMS... • Enroll “Mary Johnson” in “CSE444”: Write a C program to do the following: ...
Database Management System
... So little fear of concurrency or transaction issues. Microsoft Azure SQL is an exception. Need to handle concurrency (and transactions/logs) in your own code. Always use optimistic concurrency (not pessimistic locking). See Chapter 7, but keep the original values when you read data and use ...
... So little fear of concurrency or transaction issues. Microsoft Azure SQL is an exception. Need to handle concurrency (and transactions/logs) in your own code. Always use optimistic concurrency (not pessimistic locking). See Chapter 7, but keep the original values when you read data and use ...
+ Database Consistency
... A deposit transaction that increments the balance by the wrong amount maintains the integrity constraint balance 0, but does not maintain the relation between the enterprise and database states ...
... A deposit transaction that increments the balance by the wrong amount maintains the integrity constraint balance 0, but does not maintain the relation between the enterprise and database states ...
1. Introduction
... Informally, a data model is a type of data abstraction that is used to provide conceptual representation. The data model uses logical concepts, such as objects, their properties, and their interrelationships, that may be easier for most users to understand than computer storage concepts. Hence, the ...
... Informally, a data model is a type of data abstraction that is used to provide conceptual representation. The data model uses logical concepts, such as objects, their properties, and their interrelationships, that may be easier for most users to understand than computer storage concepts. Hence, the ...
comp4_unit6-1_audio_transcript
... would need to delete the contact person. However, on a disk file you'd also be deleting the information about the ambulance company itself because the contact information and the company information would often be kept in one record. In a disk file an entire record must be deleted. Databases have a ...
... would need to delete the contact person. However, on a disk file you'd also be deleting the information about the ambulance company itself because the contact information and the company information would often be kept in one record. In a disk file an entire record must be deleted. Databases have a ...
presentation - University of Reading
... • An application serves a group of users, and gives them an interface to transactions that access a database. • Electronic commerce is a prominent source of database applications. • User interface design needs care if the users are to be well-served. April 2002 ...
... • An application serves a group of users, and gives them an interface to transactions that access a database. • Electronic commerce is a prominent source of database applications. • User interface design needs care if the users are to be well-served. April 2002 ...
syllabus - Sharada Vikas Trust
... The Entity-Relationship Data Model, Introduction of entity Relationship model, Elements of the E/R Model, Requirement, Relationship, Entity-Relationship Diagrams, Multiplicity of Binary E/R Relationships, Design Principles, Avoiding Redundancy, Simplicity Counts, Extended ER Models ...
... The Entity-Relationship Data Model, Introduction of entity Relationship model, Elements of the E/R Model, Requirement, Relationship, Entity-Relationship Diagrams, Multiplicity of Binary E/R Relationships, Design Principles, Avoiding Redundancy, Simplicity Counts, Extended ER Models ...
Powerpoint - Mathematical & Computer Sciences
... • Is a DBMS designed to provide high performance on complex queries against real-world sized database. • Achieves this goal using innovations at all layers of a DBMS: a storage model based on vertical fragmentation, ...
... • Is a DBMS designed to provide high performance on complex queries against real-world sized database. • Achieves this goal using innovations at all layers of a DBMS: a storage model based on vertical fragmentation, ...
Part 1
... Rows are sets of values for the columns (attribute values) Primary key: a set of columns that uniquely identifies each row Each row must be unique given the primary key (no duplicates) Rows are referenced by the primary key Row order cannot be determined by the user Does not make sense to say “the f ...
... Rows are sets of values for the columns (attribute values) Primary key: a set of columns that uniquely identifies each row Each row must be unique given the primary key (no duplicates) Rows are referenced by the primary key Row order cannot be determined by the user Does not make sense to say “the f ...
An Introduction to Distributed Applications and Ecommerce
... Clients and servers A server provides a service such as ...
... Clients and servers A server provides a service such as ...
Universal Database Integration System
... The current application can be categorized into the following modules, which are closely linked with one another. 1. Structure This module provides the list of all tables which are present in the selected or current user. This module is used to view and browse the structure of an existing database. ...
... The current application can be categorized into the following modules, which are closely linked with one another. 1. Structure This module provides the list of all tables which are present in the selected or current user. This module is used to view and browse the structure of an existing database. ...