i o configuration and design

... device in terms of a device identifier and simple commands such as open, close, read, write • Device I/O: – Converts requested operations into sequence of I/O instructions Trang 4A Model of I/O ... suspended process is blocked waiting on the I/O event, and the I/O operation is blocked waiting for the process to be swapped in Trang 11I/O Buffering• It may be more efficient to perform input transfers ... Multiprogramming allows some processes to be waiting on I/O while another process is executing Trang 6Goal: Efficiency• Swapping brings in ready processes but this is an I/O operation itself • A major...

Ngày tải lên: 30/01/2020, 05:13

... resolution BGP is a routing information distribution protocol that defines who can talk to whom using multi-protocol extensions and community attributes VPN membership depends upon logical ports ... once it occurs WRED is designed to avoid congestion in internetworks before it becomes a problem It leverages the flow monitoring capabilities of TCP It monitors traffic load at points in the ... filter out all routes with the “wrong” VPN of Origin.52 These two attributes allow great flexibility in allowing one to control the distribution of routing information among various sets of sites,...

Ngày tải lên: 21/12/2013, 19:15

... subtraction Symbol Meaning + addition operator % attribute indicator ' character string delimiter component selector / division operator ( expression or list delimiter ) expression or list delimiter ... salesperson The bonus is based on salary and commission If the commission is null, you raise the exception comm_missing DECLARE comm_missing EXCEPTION; declare exception BEGIN IF commission IS NULL ... data Native compilation is easier and more integrated, with fewer initialization parameters to set, less compiler configuration, the object code stored in the database, and compatibility with Oracle...

Ngày tải lên: 24/01/2014, 08:20

... NULLs and the NOT Operator Conditional Compilation How Does Conditional Compilation Work? Conditional Compilation Control Tokens Using Conditional Compilation ... Compilation Selection Directives Using Conditional Compilation Error Directives Using Conditional Compilation Inquiry Directives Using Predefined Inquiry Directives With Conditional ... http://www.oracle.com/technology/documentation/ For information on additional books http://www.oracle.com/technology/books/10g_books.html Conventions This section describes the conventions used in the text and code examples of this documentation...

Ngày tải lên: 30/03/2014, 22:20

... application programming and familiarity with SQL to access information in relational database systems Some sections also assume a knowledge of basic object-oriented programming Organization See ... you can go directly to the documentation section of the OTN Web site at http://otn.oracle.com/docs/index.htm xxviii Conventions This section describes the conventions used in the text and code ... examples of this documentation set It describes: s Conventions in Text s Conventions in Code Examples Conventions in Text We use various conventions in text to help you more quickly identify special...

Ngày tải lên: 24/10/2013, 17:15

... prior written permission of Oracle Corporation Any other copying is a violation of copyright law and may result in civil and/ or criminal penalties If this documentation is delivered to a U.S Government ... the following: • Process Oracle server errors with exception-handling routines • Declare user-defined error conditions and process them with exception-handling routines Introduction to Oracle 9i: ... multiple applications – • Routines online without interfering with other users One routine to eliminate duplicate testing Improved data security and integrity by doing the following: – – • Control...

Ngày tải lên: 27/10/2013, 22:15

... from within your command file SQL*Plus Format Commands You can control the report features described above by using the following commands: Command Purpose COL[UMN] [column option] Controls column ... Practice C Solutions continued Load and execute a loop counter a Launch SQL*Plus Your instructor will give you the login information b Start the LABS\pcloop.sql file to create the COUNT_LOOPS procedure ... PL/SQL code, one of two types of errors might appear One type is a compilation error For anonymous blocks, you will see the errors appear on the screen For stored subprograms, the compilation errors...

Ngày tải lên: 17/01/2014, 09:20

... expression or list delimiter expression or list delimiter host variable indicator item separator multiplication operator quoted identifier delimiter relational operator relational operator relational ... C, or COBOL You will not find installation instructions or system-specific information in this guide For that kind of information, see the Oracle installation or user’s guide for your system How ... is prohibited The information contained in this document is subject to change without notice If you find any problems in the documentation, please report them to us in writing Oracle Corporation...

Ngày tải lên: 17/01/2014, 09:20

... Introduction System Development Life Cycle Strategy and Analysis Design Build and Document Transition Production Additional Information If time permits, share the following information with ... Operator Precedence _ * / + • Multiplication and division take priority over addition and subtraction Hint Explain that if your arithmetic expression contains more than one operator, the priority ... Oracle Corporation Any other copying is a violation of copyright law and may result in civil and/ or criminal penalties If this documentation is delivered to a U.S Government Agency not within the...

Ngày tải lên: 24/01/2014, 10:20

... C, or COBOL You will not find installation instructions or system-specific information in this guide For that kind of information, see the Oracle installation or user’s guide for your system How ... operator % attribute indicator ’ character string delimiter component selector / division operator ( expression or list delimiter ) expression or list delimiter : host variable indicator , item ... is prohibited The information contained in this document is subject to change without notice If you find any problems in the documentation, please report them to us in writing Oracle Corporation...

Ngày tải lên: 07/08/2014, 11:22

... specifier must be followed by an initialization clause Otherwise, you get a compilation error For example, the following declaration is illegal: line_items POSITIVEN; illegal; not initialized ... as follows: LOOP LOOP EXIT outer WHEN END LOOP; END LOOP outer; exit both loops Every enclosing loop up to and including the labeled loop is exited WHILE-LOOP The WHILE-LOOP statement ... Operator Operation **, NOT exponentiation, logical negation +, - identity, negation *, / multiplication, division +, -, || addition, subtraction, concatenation =, , =, , !=, ~=, ^=, IS...

Ngày tải lên: 07/08/2014, 11:22

... and Comparing Collections If you assign an atomically null collection to another collection, the other collection becomes atomically null (and must be reinitialized) Consider the following example: ... easier to maintain: EXISTS COUNT LIMIT FIRST and LAST PRIOR and NEXT EXTEND TRIM DELETE A collection method is a built-in function or procedure that operates on collections and is called using ... applied to atomically null collections If you apply another method to such collections, PL/SQL raises COLLECTION_IS_NULL Collections and Records 4-21 Using Collection Methods Using EXISTS EXISTS(n)...

Ngày tải lên: 07/08/2014, 11:22

... transaction Remember, autonomous transactions are fully independent of the main transaction Avoiding Errors To avoid some common errors, keep the following points in mind when designing autonomous ... finish autonomous transactions on their own A calling application need not know about a procedure’s autonomous operations, and the procedure need not know about the application’s transaction context ... the commit or rollback in your PL/SQL program or in the host environment depends on the flow of application logic If you neglect to commit or roll back a transaction explicitly, the host environment...

Ngày tải lên: 07/08/2014, 11:22

... credit_acct(acct_no => acct, amount => amt); named credit_acct(acct, amount => amt); mixed notation notation notation notation Using Positional Notation The first procedure call uses positional notation ... Therefore, you can design applications from the top down without worrying about implementation details Dummy subprograms (stubs) allow you to defer the definition of procedures and functions until you ... exception Handling Raised Exceptions When an exception is raised, normal execution of your PL/SQL block or subprogram stops and control transfers to its exception-handling part, which is formatted...

Ngày tải lên: 07/08/2014, 11:22

... Easier Application Design When designing an application, all you need initially is the interface information in the package specs You can code and compile a spec without its body Then, stored ... which are visible to your application The body holds implementation details and private declarations, which are hidden from your application Following the declarative part of the package body is ... SERIALLY_REUSABLE;] [collection_type_definition ] [record_type_definition ] [subtype_definition ] [collection_declaration ] [constant_declaration ] [exception_declaration ] [object_declaration...

Ngày tải lên: 07/08/2014, 11:22

... exception goes unhandled If you try to exit an active autonomous transaction without committing or rolling back, Oracle raises an exception If the exception goes unhandled, the transaction is rolled ... for nullity However, they cannot be compared for equality or inequality This restriction also applies to implicit comparisons For example, collections cannot appear in a DISTINCT, GROUP BY, or ... Collection Methods A collection method is a built-in function or procedure that operates on collections and is called using dot notation The methods EXISTS, COUNT, LIMIT, FIRST, LAST, PRIOR, NEXT,...

Ngày tải lên: 07/08/2014, 11:22