Certain database errors are caused by pre
Certain database errors are caused by pre

... ? , ? , ? , ? , ? , ? , ? , ? , ? , ? , ? ) ' for an instance of class PIPING_NETWORK_SEGMENT because of an exception of the type OleDbException with the message 'The changes you requested to the table were not successful because they would create duplicate values in the index, primary key, or relat ...
Dunkins Project Study Aim: To generate Db for a local Donut Store
Dunkins Project Study Aim: To generate Db for a local Donut Store

... To learn complex aspects of Microstrategy using this database in MSTR ( eg fact extension, custom facts, partition mappings, function and operations etc etc) ...
DIRECT CAR INSURANCE Relational Database Conversion Project
DIRECT CAR INSURANCE Relational Database Conversion Project

VIEWS_EPA_Data_Summit_200802
VIEWS_EPA_Data_Summit_200802

... What is VIEWS? The Visibility Information Exchange Web System is a database system and set of online tools originally designed to support the Regional Haze Rule enacted by the EPA to reduce regional haze in national parks and wilderness areas. ...
Hack Your DB Before The Hackers Do!
Hack Your DB Before The Hackers Do!

5-37 Distributed Databases
5-37 Distributed Databases

... • The foundation of modern methods of managing organizational data • Consolidates data records formerly in separate files into databases • Data can be accessed by many different application programs • A database management system (DBMS) is the software interface between users and databases ...
Designing Real-time Sensor Data Warehouse Architecture Using
Designing Real-time Sensor Data Warehouse Architecture Using

... The trunk has a history of changes as a file evolves. Diffs or Deltas are the changes I made while editing ...
Document
Document

... SQL > ALTER TABLE MODIFY ( (SIZE), (SIZE)……); SQL> alter table student modify(roll_no number(7),address varchar2(3)); Table altered. SQL> desc student; Name Null? Type ----------------------------------------- -------- ----------------- ...
SQL Server Summit: Achieving High Availability with SQL Server
SQL Server Summit: Achieving High Availability with SQL Server

... data transfer at about 16 GB / hour, taking full advantage of the DS3. This transfer rate easily met USDA’s needs for initial synchronization, daily log shipping, and the fail-back process. The working read-only version of the fail-over database meant that the administrators always knew the status o ...
Windows Azure Platform in 30minutes
Windows Azure Platform in 30minutes

... using existing skills and integrate with your existing on-premise applications ...
Comments on IT/GIS Elements - Society for Hawaiian Archaeology
Comments on IT/GIS Elements - Society for Hawaiian Archaeology

... The SHPD inventory database plan submitted does not represent collaboration between the SHPD IT staff and the SHPD cultural resource professionals, other than to gather survey forms and incorporate basic information. The plan also does not reflect any use or functionality outlined by the SHPD staff ...
Enterprise Library
Enterprise Library

Module 8: Implementing Managed Code in the Database
Module 8: Implementing Managed Code in the Database

... Specify a database object name for the assembly Reference the assembly file Set assembly trust level (optional) CREATE ASSEMBLY Contacts FROM 'C:\ContactsApp\Contacts.dll' WITH PERMISSION_SET = SAFE -- default value ...
Spatial Database Engine
Spatial Database Engine

... • ArcSDE is an engine residing between a spatiallyenabled RDBMS and ArcGIS desktop. • ArcSDE and the GDB enables GIS for the Enterprise ...
Chapter 1 Overview of Database Concepts
Chapter 1 Overview of Database Concepts

... • Display multiple columns of a table • Use a column alias to clarify the contents of a particular column • Perform basic arithmetic operations in the SELECT clause ...
SX5
SX5

... 30. A computer file contains several records. What does each record contain? (a) Bytes (b) Words (c) Fields (d) Programs 31. What name is given to the collection of facts, items of information or data which are related in some way? (a) Data base (b) Directory information (c) Information tree (d) Inf ...
Horticulture
Horticulture

... 1. Select the most frequently accessed column in each table as the horizontal partitioning attribute 2. Greedily replicate read-only tables until no space left 3. Select next most frequently accessed, read-only column as secondary index attribute for each table 4. Select the routing parameter for st ...
CS 7700 Transaction Design for Microsoft Access Database with
CS 7700 Transaction Design for Microsoft Access Database with

... The data in a ResultSet object is accessed through a cursor, which points to its current row of data in the ResultSet. When a ResultSet object is first created, the cursor is positioned before the first row. The next method moves the cursor to the next row. The ResultSet interface provides getter m ...
High Availability with Microsoft SQL Server
High Availability with Microsoft SQL Server

... [Skip if time is running short.] ...
Issues in Bridging DB & IR
Issues in Bridging DB & IR

... Useful for plagiarism detection (see Turnitin software does it..) ...
Chapter 5: Data Resource Management
Chapter 5: Data Resource Management

... packages that simplify the creation, use, and maintenance of databases. • Several types of databases are used by organizations including operational, distributed, external, data warehouses and data marts. • Database development for large corporate databases requires a top-down planning effort involv ...
Views-basics
Views-basics

...  users and user programs are immune to changes in the logical structure of the DB  to what extent logical data independence can be guaranteed? ...
Slide 1
Slide 1

... sp_changeobjectowner permissions has an additional requirement. In order for a member of the db_ddladmin role to be able to successfully call sp_changeobjectowner, the member must also be a member of the db_securityadmin database role. When an object’s owner is changed, permissions are changed as we ...
Phase 2, Answering queries using views.
Phase 2, Answering queries using views.

... When the event happens, the system will check the constraint, and if satisfied, will perform the action. NOTE: triggers may cause cascading effects. Database vendors did not wait for standards with triggers! ...
1. Introduction to SQL Tuning
1. Introduction to SQL Tuning

... Ø Memory Processes - You must understand the purpose of the shared pool and database buffer cache. Ø Database Objects - It is not possible to tune an SQL statement without understanding indexes! Data storage in tables or clusters can also have an effect. Ø Access Paths - The Oracle optimizer can cho ...

Relational model



The relational model for database management is an approach to managing data using a structure and language consistent with first-order predicate logic, first described in 1969 by Edgar F. Codd. In the relational model of a database, all data is represented in terms of tuples, grouped into relations. A database organized in terms of the relational model is a relational database.The purpose of the relational model is to provide a declarative method for specifying data and queries: users directly state what information the database contains and what information they want from it, and let the database management system software take care of describing data structures for storing the data and retrieval procedures for answering queries.Most relational databases use the SQL data definition and query language; these systems implement what can be regarded as an engineering approximation to the relational model. A table in an SQL database schema corresponds to a predicate variable; the contents of a table to a relation; key constraints, other constraints, and SQL queries correspond to predicates. However, SQL databases deviate from the relational model in many details, and Codd fiercely argued against deviations that compromise the original principles.