Database performance tuning
... Measure of the likelihood that an index will be used in query processing Indexes are used when a subset of rows from a large table is to be selected based on a given condition Index cannot always be used to improve performance Function-based index: Based on a specific SQL function or expression ...
... Measure of the likelihood that an index will be used in query processing Indexes are used when a subset of rows from a large table is to be selected based on a given condition Index cannot always be used to improve performance Function-based index: Based on a specific SQL function or expression ...
Oracle Application Express
... apps/reports; wizards Access to any table in database (with perms) Can customize processing with PL/SQL Powerful Interactive Reports for sorting/filtering results Can run on your SSB web server (DAD) ...
... apps/reports; wizards Access to any table in database (with perms) Can customize processing with PL/SQL Powerful Interactive Reports for sorting/filtering results Can run on your SSB web server (DAD) ...
Accelerating SQL Database Operations on a GPU
... • Average query speedup of 35X • Two goals: – Accelerate existing database operations – Give programmers easier access to GPU hardware ...
... • Average query speedup of 35X • Two goals: – Accelerate existing database operations – Give programmers easier access to GPU hardware ...
2440: 180 Database Concepts - gozips.uakron.edu
... • Fragmentation transparency • Replication transparency ...
... • Fragmentation transparency • Replication transparency ...
Database
... available flights on corporate jets – Companies phone in available seats • They want to know about interested passengers ...
... available flights on corporate jets – Companies phone in available seats • They want to know about interested passengers ...
Lecture Notes - Duncan College
... (unaffected by any other users). Transactions may “lock” certain areas of the database, preventing concurrent access to these areas. Do not leave them open for extended periods of time. If T1 and T2 are executed simultaneously, end behavior is either T1; T2; or T2; T1; ...
... (unaffected by any other users). Transactions may “lock” certain areas of the database, preventing concurrent access to these areas. Do not leave them open for extended periods of time. If T1 and T2 are executed simultaneously, end behavior is either T1; T2; or T2; T1; ...
Security Plans
... When asking for a customer number, check that input is the proper data type, length, etc., before executing the query. Limit the permissions of the account that executes SQL queries. Use stored procedures (or similar techniques) to prevent users from directly interacting with SQL code. ...
... When asking for a customer number, check that input is the proper data type, length, etc., before executing the query. Limit the permissions of the account that executes SQL queries. Use stored procedures (or similar techniques) to prevent users from directly interacting with SQL code. ...
name varchar
... No need to go through SQL. No need for explicit format (type) changes format changes are carried out transparently by system Without a persistent programming language, format changes becomes a burden on the programmer ...
... No need to go through SQL. No need for explicit format (type) changes format changes are carried out transparently by system Without a persistent programming language, format changes becomes a burden on the programmer ...
Normalisation Example2
... – 2NF is better than 1NF; 3NF is better than 2NF – For most business database design purposes, 3NF is as high as needed in normalization – Highest level of normalization is not always most desirable ...
... – 2NF is better than 1NF; 3NF is better than 2NF – For most business database design purposes, 3NF is as high as needed in normalization – Highest level of normalization is not always most desirable ...
Access2007-1-What is Access
... What is a Database? A variety of definitions exist for a database; but essentially it is a collection of information, regardless of how that information is stored. A filing cabinet, a Rolodex, a library card catalog and the Internet are all types of databases. Most often, however, the word "database ...
... What is a Database? A variety of definitions exist for a database; but essentially it is a collection of information, regardless of how that information is stored. A filing cabinet, a Rolodex, a library card catalog and the Internet are all types of databases. Most often, however, the word "database ...
Modelling the `Real` World
... In this Workshop we will begin to explore some of the decisions we must make as we attempt to construct a model of ‘real’ world ‘things’. Working alone, or in a small team, consider the following half dozen ‘things’ that exist in the ‘real’ world. ...
... In this Workshop we will begin to explore some of the decisions we must make as we attempt to construct a model of ‘real’ world ‘things’. Working alone, or in a small team, consider the following half dozen ‘things’ that exist in the ‘real’ world. ...
MS ACCESS
... originally created by Stan Leszynski and Greg Reddick, developed guidelines called tags to assist the user to open, edit, and troubleshootwithout deciphering what is contained within the object itself. • File names can be more than one word; however, do not use underscores or spaces. Instead, capita ...
... originally created by Stan Leszynski and Greg Reddick, developed guidelines called tags to assist the user to open, edit, and troubleshootwithout deciphering what is contained within the object itself. • File names can be more than one word; however, do not use underscores or spaces. Instead, capita ...
query - Reach
... a unique value. e.g. The SSN • Foreign key is the primary key of another table. e.g. suppose we need to link the employee table with the Hours worked table for payroll purposes. The Employee ID number (EIN) is the primary key of the employees table but the foreign key of the hours worked table. *Eve ...
... a unique value. e.g. The SSN • Foreign key is the primary key of another table. e.g. suppose we need to link the employee table with the Hours worked table for payroll purposes. The Employee ID number (EIN) is the primary key of the employees table but the foreign key of the hours worked table. *Eve ...
Fact table - WordPress.com
... system (usually ERP or CRM system) and a DataWarehouse is that the system’s relational model is usually de-normalized into dimension and fact tables which are typical to a data warehouse database design. The differences in the database architectures are caused by different purposes of their existenc ...
... system (usually ERP or CRM system) and a DataWarehouse is that the system’s relational model is usually de-normalized into dimension and fact tables which are typical to a data warehouse database design. The differences in the database architectures are caused by different purposes of their existenc ...
Semantic Wrapper over Relational Databases
... Semantic Data Model Benefits (Cont.) Semantic Views over Relational Schemas – Higher level data model – Semantic view mirrors real world – Flexible classification of objects – Complex relations made simple: arbitrary relationships – Semantically-Enhanced Object-Relational – Information in its Natur ...
... Semantic Data Model Benefits (Cont.) Semantic Views over Relational Schemas – Higher level data model – Semantic view mirrors real world – Flexible classification of objects – Complex relations made simple: arbitrary relationships – Semantically-Enhanced Object-Relational – Information in its Natur ...
The Why and How of the iModernize(d) Application
... Level Store is a way of treating all storage attached to IBM i as if it is one huge set of memory. Working with DB2, our storage management spreads data across a customer's DASD in order to optimize data access. For these two reasons, customers rarely have to hire storage administrators or database ...
... Level Store is a way of treating all storage attached to IBM i as if it is one huge set of memory. Working with DB2, our storage management spreads data across a customer's DASD in order to optimize data access. For these two reasons, customers rarely have to hire storage administrators or database ...
Document
... – Overhead of requesting and getting locks from server is high due to message delays – Can grant locks on requested and prefetched items; with page shipping, transaction is granted lock on whole page. – Locks on a prefetched item can be called back by the server, and returned by client transaction i ...
... – Overhead of requesting and getting locks from server is high due to message delays – Can grant locks on requested and prefetched items; with page shipping, transaction is granted lock on whole page. – Locks on a prefetched item can be called back by the server, and returned by client transaction i ...
Database Users
... without changing the logical schema Applications depend on the logical schema In general, the interfaces between the various levels and components should be well defined so that changes in some parts do not seriously influence others. ...
... without changing the logical schema Applications depend on the logical schema In general, the interfaces between the various levels and components should be well defined so that changes in some parts do not seriously influence others. ...
SQL Overview
... When you are executing an SQL command for any RDBMS, the system determines the best way to carry out your request and SQL engine figures out how to interpret the task. There are various components included in the process. These components are Query Dispatcher, Optimization Engines, Classic Query En ...
... When you are executing an SQL command for any RDBMS, the system determines the best way to carry out your request and SQL engine figures out how to interpret the task. There are various components included in the process. These components are Query Dispatcher, Optimization Engines, Classic Query En ...
Document
... Many new methods to navigate: – afterLast(); //position pointer after last row – previous(); //opposite of next() – absolute(i);//go to the i’th row – absolute(-i);//go to the i’th row from end – relative(i);//go i rows away from this point – getRow();/returns current row – isFirst(), isLast(), is ...
... Many new methods to navigate: – afterLast(); //position pointer after last row – previous(); //opposite of next() – absolute(i);//go to the i’th row – absolute(-i);//go to the i’th row from end – relative(i);//go i rows away from this point – getRow();/returns current row – isFirst(), isLast(), is ...
Notes
... PRIMARY (A1, A2, .., An) or UNIQUE (A1, A2, ..., An) Insertions: check if any tuple has same values for A1, A2, .., An as any inserted tuple. If found, reject insertion Updates to any of A1, A2, ..., An: treat as insertion of entire tuple Primary vs Unique (candidate) 1. 1 primary key per table, sev ...
... PRIMARY (A1, A2, .., An) or UNIQUE (A1, A2, ..., An) Insertions: check if any tuple has same values for A1, A2, .., An as any inserted tuple. If found, reject insertion Updates to any of A1, A2, ..., An: treat as insertion of entire tuple Primary vs Unique (candidate) 1. 1 primary key per table, sev ...
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.