grupo de registros vacío, lo que es contrario a la lógica común. Manejo de NULL en UDF's Las UDF's (User Defined Functions o Funciones Definidas por el Usuario) son funciones no internas en el motor, por UDF's, consulta la InterBase 6.0 Developer's Guide (libre en http://www.ibphoenix. com/downloads/60DevGuide.zip), Using Firebird y la Firebird Reference Guide (ambas en CD), o el Firebird Book. El libro http://www.firebirdsql.org/ma- nual/pdl.html (HTML). La documentación original se llama Firebird Null Guide. El escritor inicial de la documentación original es: Paul Vinkenoog. Copyright © 2005. Todos los

2. Escriba lo siguiente (sensible a mayúsculas en todas las plataformas excepto Windows): gsec -user sysdba -password masterkey Debería ver el prompt de la utilidad gsec : GSEC> 3. Escriba este comando: specify a database SQL>CONNECT "C:\Program Files\Firebird\Firebird_1_5\examples\employee.fdb"# CON>user 'SYSDBA' password 'masterkey';# Importante En isql, cada sentencia SQL debe finalizar con un punto se ha conectado: DATABASE "C:\Archivos de programa\Firebird\Firebird_1_5\examples\employee.fdb", User: sysdba SQL> Ahora puede seguir jugando con la base de datos employee.fdb. Los caracteres isql significan

participant User User -> A: DoWork activate A A -> B: << createRequest >> activate B B -> C: DoWork activate C C --> B: WorkDone destroy C B --> A: RequestCreated deactivate B A -> User: Done deactivate participant User User -> A: DoWork activate A #FFBBBB A -> A: Internal call activate A #DarkSalmon A -> B: << createRequest >> activate B B --> A: RequestCreated deactivate B deactivate A A -> User: Done 60 skinparam sequenceParticipant underline actor User participant "First Class" as A participant "Second Class" as B participant "Last Class" as C User -> A: DoWork activate A Guía de Referencia del Lenguaje

participant User User -> A: DoWork activate A A -> B: << createRequest >> activate B B -> C: DoWork activate C C --> B: WorkDone destroy C B --> A: RequestCreated deactivate B A -> User: Done deactivate participant User User -> A: DoWork activate A #FFBBBB A -> A: Internal call activate A #DarkSalmon A -> B: << createRequest >> activate B B --> A: RequestCreated deactivate B deactivate A A -> User: Done 60 skinparam sequenceParticipant underline actor User participant "First Class" as A participant "Second Class" as B participant "Last Class" as C User -> A: DoWork activate A Guía de Referencia del Lenguaje

participant User User -> A: DoWork activate A A -> B: << createRequest >> activate B B -> C: DoWork activate C C --> B: WorkDone destroy C B --> A: RequestCreated deactivate B A -> User: Done deactivate participant User User -> A: DoWork activate A #FFBBBB A -> A: Internal call activate A #DarkSalmon A -> B: << createRequest >> activate B B --> A: RequestCreated deactivate B deactivate A A -> User: Done 60 skinparam sequenceParticipant underline actor User participant "First Class" as A participant "Second Class" as B participant "Last Class" as C User -> A: DoWork activate A A -> B: Create Request activate

participant User User -> A: DoWork activate A A -> B: << createRequest >> activate B B -> C: DoWork activate C C --> B: WorkDone destroy C B --> A: RequestCreated deactivate B A -> User: Done deactivate participant User User -> A: DoWork activate A #FFBBBB A -> A: Internal call activate A #DarkSalmon A -> B: << createRequest >> activate B B --> A: RequestCreated deactivate B deactivate A A -> User: Done 60 skinparam sequenceParticipant underline actor User participant "First Class" as A participant "Second Class" as B participant "Last Class" as C User -> A: DoWork activate A A -> B: Create Request activate

participant User User -> A: DoWork activate A A -> B: << createRequest >> activate B B -> C: DoWork activate C C --> B: WorkDone destroy C B --> A: RequestCreated deactivate B A -> User: Done deactivate participant User User -> A: DoWork activate A #FFBBBB A -> A: Internal call activate A #DarkSalmon A -> B: << createRequest >> activate B B --> A: RequestCreated deactivate B deactivate A A -> User: Done 60 skinparam sequenceParticipant underline actor User participant "First Class" as A participant "Second Class" as B participant "Last Class" as C User -> A: DoWork activate A A -> B: Create Request activate

participant User User -> A: DoWork activate A A -> B: << createRequest >> activate B B -> C: DoWork activate C C --> B: WorkDone destroy C B --> A: RequestCreated deactivate B A -> User: Done deactivate participant User User -> A: DoWork activate A #FFBBBB A -> A: Internal call activate A #DarkSalmon A -> B: << createRequest >> activate B B --> A: RequestCreated deactivate B deactivate A A -> User: Done 60 skinparam sequenceParticipant underline actor User participant "First Class" as A participant "Second Class" as B participant "Last Class" as C User -> A: DoWork activate A A -> B: Create Request activate

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115 6.1.1. Spoofing de la cadena User-Agent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116 6.1.2. extensión presentación simple con ejemplos del intérprete de órdenesbash(1). # command-in-root-account $ command-in-user-account Estos cursores del intérprete de órdenes diferencian el tipo de cuenta que tiene asociada ”LANG=en_US.UTF8”. No espere cadenas de marcador de posición como command-in-root-account y command-in-user-account para traducirse en ejemplos de comandos. Esta es una elección intencionada para mantener actualizados

participant User User -> A: DoWork activate A A -> B: << createRequest >> activate B B -> C: DoWork activate C C --> B: WorkDone destroy C B --> A: RequestCreated deactivate B A -> User: Done deactivate de líneas de vida, y es posible agregar un color a dicha línea de vida. @startuml participant User User -> A: DoWork activate A #FFBBBB A -> A: Internal call activate A #DarkSalmon A -> B: << createRequest PlantUML (1.2019.4) 15 / 165 1.20 Return 1 DIAGRAMA DE SECUENCIA deactivate B deactivate A A -> User: Done deactivate A @enduml 1.20 Return A new command return for generating a return message with