Detailed explanation of call/apply, arguments, and undefined/null methods in JS_javascript skills
a.Detailed explanation of call and apply methods ————————————————– ———————————- call method: Syntax: call([thisObj[,arg1[, arg2[, [,.argN]]]]]) Definition: Call a method of an object to replace the current object with another object. Description: The call method can be used to call a method instead of another object. The call method changes the object context of a function from the initial context to the new object specified by thisObj. If no thisObj parameter is provided, the Global object is used as thisObj. apply method: Syntax: apply([thisObj[,argArray]]) Definition: Apply a method of an object to replace the current object with another object. Note: If argArray is not a valid array or is not an arguments object, a TypeError will be caused. If neither argArray nor thisObj are provided, the Global object will be used as thisObj and no parameters can be passed. Example learning: function add(a,b){ alert(a+b);} function sub(a,b){ alert(a-b);} add.call(sub,3,1); The printed result is 4. The add function is called, but the calling object (context) is not the add object, but the sub function object. Note: Functions in js are actually objects, and the function name is a reference to the Function object. function Animal(){ this.name = “Animal”; this.showName = function(){ alert(this.name);} }…
ORA-00600: problem with internalerrorcode, arguments..
ORA-00600: problem with internal error code, arguments.. the Symptoms: When querying the wwl005 table, an internal error is reported. We just performed inconsistency recovery for this table, and then the following error is reported in the query. This phenomenon is generally caused by bugs or bad blocks. 15:43:53 SQL> select * from wwl005; select * from wwl005 * ERROR at line 1: ORA-00600: internal error code, arguments: [kcbz_check_objd_typ_3], [0], [0], [1], [], [], [], [] Analysis failure: First check the alert log and find that there is an error, but it is not clear: Errors in file /DBSoft/admin/WWL/udump/wwl_ora_4724.trc: ORA-00600: internal error code, arguments: [kcbz_check_objd_typ_3], [0], [0], [1], [], [], [], [] www.2cto.com the Then check the corresponding trace file to see: [root@wwldb ~]# cat /DBSoft/admin/WWL/udump/wwl_ora_4724.trc |more Dump file /DBSoft/admin/WWL/udump/wwl_ora_4724.trc Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 – Production With the Partitioning, OLAP and Data Mining options ORACLE_HOME = /DBSoft/product/10.2.0/db_1 System name: Linux Node name: wwldb.localdomain Release: 2.6.18-164.el5 Version: #1 SMP Thu Sep 3 02:16:47 EDT 2009 Machine: i686 Instance name: WWL Redo thread mounted by this instance: 1 Oracle process number: 12 Unix process pid: 4724, image: [email protected] (TNS V1-V3) *** ACTION NAME: () 2012-07-10 15:44:04.239 *** MODULE NAME: (SQL*Plus)…
