Oracle数据库系统应用开发实用教程电子课件 第2章 Oracle的体系结构.ppt

* * Starting Up a Database When starting the database, you select the state in which it starts. The following scenarios describe different stages of starting up an instance. Starting the Instance (NOMOUNT) An instance would be started in the NOMOUNT stage only during database creation or the re-creation of control files. Starting an instance includes the following tasks: Reading the initialization file from $ORACLE_HOME/database in the following order: First spfileSID.ora If not found then, spfile.ora If not found then, initSID.ora Specifying the PFILE parameter with STARTUP overrides the default behavior. Allocating the SGA Starting the background processes Opening the alertSID.log file and the trace files The database must be named with the DB_NAME parameter either in the initialization parameter file or in the STARTUP command. * Starting Up a Database When starting the database, you select the state in which it starts. The following scenarios describe different stages of starting up an instance. Starting the Instance (NOMOUNT) An instance would be started in the NOMOUNT stage only during database creation or the re-creation of control files. Starting an instance includes the following tasks: Reading the initialization file from $ORACLE_HOME/database in the following order: First spfileSID.ora If not found then, spfile.ora If not found then, initSID.ora Specifying the PFILE parameter with STARTUP overrides the default behavior. Allocating the SGA Starting the background processes Opening the alertSID.log file and the trace files The database must be named with the DB_NAME parameter either in the initialization parameter file or in the STARTUP command. * Starting Up a Database When starting the database, you select the state in which it starts. The following scenarios describe different stages of starting up an instance. Starting the Instance (NOMOUNT) An instance would be started in the NOMOUNT stage only during database creation or the re-creation of control fi