Click the download link and save the JavaScript file to a new working folder, ready for playing with. You’ll need to put it where our HTML files can see it: commonly in a scripts or javascript directory beneath your site’s document root To make it all work, we need to tell our HTML file to include the jQuery library.
<head>
<title>Hello jQuery world!</title>
<script type='text/javascript' src='jquery-1.4-min.js'></script>
<script type='text/javascript' src='script.js'></script>
</head>
The first script tag on the page loads the jQuery library, and the second script tag points to a script.js file, which is where we’ll run our own jQuery code.
Saturday, January 15, 2011
Memory Used by an Instance
System Global Area
The System Global Area (SGA) is an area of memory that is accessible to all user processes of an Oracle
instance. Three main areas are used by the SGA:
❑ The redo log buffer holds information used for recovery until the information can be written to
the redo log.
❑ The shared pool holds information that can be shared across user processes, such as execution
plans for SQL statements, compiled stored procedures, and information retrieved from the
Oracle data dictionary.
❑ The database buffer pools are a group of memory areas that are used to hold data blocks. A data
block held in a buffer pool can be accessed much more rapidly than going to disk to retrieve
the block, so efficient use of these memory pools is essential for achieving optimal performance.
Following are the three basic database buffer pools:
❑ The DEFAULT pool holds all database objects, unless otherwise specified.
❑ The KEEP pool is used to hold objects in memory if specified for a table or index.
❑ The RECYCLE pool is used for objects that are not likely to be reused again.
Keep the following two points in mind:
❑ For all of these pools, the Oracle instance uses a Least Recently Used (LRU)
algorithm to determine what data blocks to swap out.
❑ In addition to these main pools, the Oracle instance can also use a large pool,
which is used for shared server, backup and recovery, and I/O operations. You
can either configure a large pool or Oracle can create it automatically, if you
configure adaptive parallelism, which is described further in Chapter 2.
Program Global Area
The Program Global Area (PGA) is an area of memory that is just available to a single server process.
The PGA contains items like user variables and cursor information for an individual user’s SQL state-
ment, such as the number of rows that have been retrieved so far. The PGA is also used for sorting data
for an individual user process.
Each time a new SQL statement is received for a user, a new space in the PGA has to be initialized. To
avoid this overhead, transaction-intensive applications, such an online transaction processing (OLTP)
applications, typically use a small set of SQL statements that are continually reused by a user process,
reducing this potential source of overhead.
You can have a single server process handle more than one user process by configuring shared servers,
which are described in Chapter 2, “Using SQL.”
The System Global Area (SGA) is an area of memory that is accessible to all user processes of an Oracle
instance. Three main areas are used by the SGA:
❑ The redo log buffer holds information used for recovery until the information can be written to
the redo log.
❑ The shared pool holds information that can be shared across user processes, such as execution
plans for SQL statements, compiled stored procedures, and information retrieved from the
Oracle data dictionary.
❑ The database buffer pools are a group of memory areas that are used to hold data blocks. A data
block held in a buffer pool can be accessed much more rapidly than going to disk to retrieve
the block, so efficient use of these memory pools is essential for achieving optimal performance.
Following are the three basic database buffer pools:
❑ The DEFAULT pool holds all database objects, unless otherwise specified.
❑ The KEEP pool is used to hold objects in memory if specified for a table or index.
❑ The RECYCLE pool is used for objects that are not likely to be reused again.
Keep the following two points in mind:
❑ For all of these pools, the Oracle instance uses a Least Recently Used (LRU)
algorithm to determine what data blocks to swap out.
❑ In addition to these main pools, the Oracle instance can also use a large pool,
which is used for shared server, backup and recovery, and I/O operations. You
can either configure a large pool or Oracle can create it automatically, if you
configure adaptive parallelism, which is described further in Chapter 2.
Program Global Area
The Program Global Area (PGA) is an area of memory that is just available to a single server process.
The PGA contains items like user variables and cursor information for an individual user’s SQL state-
ment, such as the number of rows that have been retrieved so far. The PGA is also used for sorting data
for an individual user process.
Each time a new SQL statement is received for a user, a new space in the PGA has to be initialized. To
avoid this overhead, transaction-intensive applications, such an online transaction processing (OLTP)
applications, typically use a small set of SQL statements that are continually reused by a user process,
reducing this potential source of overhead.
You can have a single server process handle more than one user process by configuring shared servers,
which are described in Chapter 2, “Using SQL.”
Files Supporting an Instance
There are a number of files that are used by an instance. The basic files for storing data are discussed in the
next section on data organization. An Oracle instance has its own set of files that do not store user data
but are used to monitor and manage the Oracle instance itself.
next section on data organization. An Oracle instance has its own set of files that do not store user data
but are used to monitor and manage the Oracle instance itself.
Initialization Files
Many parameters exist that affect the way that your Oracle instance operates. These parameters are
typically set and maintained by a database administrator and, as such, are beyond the scope of this book.
The initial values for these parameters are kept in initialization files.
Many parameters exist that affect the way that your Oracle instance operates. These parameters are
typically set and maintained by a database administrator and, as such, are beyond the scope of this book.
The initial values for these parameters are kept in initialization files.
Prior to Oracle9i, each instance had its own specific initialization file called INIT.ORA, as well as an
optional file with additional configuration information called CONFIG.ORA. Starting with Oracle9i, you
could have a virtual initialization file called the SPFILE, which could be shared with multiple instances.
SPFILE was especially handy for two reasons: You could change a configuration parameter for a running
instance and not have to save the change to the SPFILE, which means that the value of the parameter
would be reset to the stored value on the next startup. You can also use the SPFILE with Real Application
Clusters, discussed later in this chapter, where multiple instances worked together in a cluster and shared
the same initialization procedures.
optional file with additional configuration information called CONFIG.ORA. Starting with Oracle9i, you
could have a virtual initialization file called the SPFILE, which could be shared with multiple instances.
SPFILE was especially handy for two reasons: You could change a configuration parameter for a running
instance and not have to save the change to the SPFILE, which means that the value of the parameter
would be reset to the stored value on the next startup. You can also use the SPFILE with Real Application
Clusters, discussed later in this chapter, where multiple instances worked together in a cluster and shared
the same initialization procedures.
Control File
The control file is used to store key information about an instance, such as the name of the instance, the
time the database was created, and the state of backup and log files for the database. An Oracle instance
requires a control file in order to operate. Although a control can be rebuilt, most Oracle installations use
multiple copies of the control file to avoid this possibility.
The control file is used to store key information about an instance, such as the name of the instance, the
time the database was created, and the state of backup and log files for the database. An Oracle instance
requires a control file in order to operate. Although a control can be rebuilt, most Oracle installations use
multiple copies of the control file to avoid this possibility.
Redo Log Files
One of key features of a relational database is its ability to recover to a logically consistent state, even in
the event of a failure. Every relational database, including Oracle, uses a set of redo log files. These files
keep track of every interaction with the database. In the event of a database failure, an administrator can
recover the database by restoring the last backup and then applying the redo log files to replay user
interactions with the database.
One of key features of a relational database is its ability to recover to a logically consistent state, even in
the event of a failure. Every relational database, including Oracle, uses a set of redo log files. These files
keep track of every interaction with the database. In the event of a database failure, an administrator can
recover the database by restoring the last backup and then applying the redo log files to replay user
interactions with the database.
Redo log files eventually fill up and roll over to start a new volume. You can set up Oracle to avoid writing
over existing logfiles by creating the database to automatically archive log files in ARCHIVELOG mode,
which is discussed in detail in the Oracle documentation.
Since redo logs are crucial for restoring a database in the event of a failure, many Oracle shops set up an
instance to keep multiple copies of a redo log file.
Rollback Segments
Unlike all other major databases, Oracle also uses rollback segments to store previous versions of data in
the database. The use of rollback segments makes it possible for the Oracle database to avoid the use of
read locks, which can significantly reduce performance degradation based on multiuser access as well as
providing a consistent view of data at any particular point in time. For more on rollback segments and
how they support multiuser concurrency, see Chapter 3, “Handling Multiple Users,” which covers this
important topic in detail.
Because rollback segments track every change to data, the rollback segments are updated as soon as a
change is made. This real-time update lets the Oracle database delay writing its redo log files until a
time when these writes can be done efficiently.
Oracle 10g includes the ability to designate an automatic UNDO tablespace, which assigns the responsibility
for managing rollback segments to the Oracle database itself.
for managing rollback segments to the Oracle database itself.
Friday, January 14, 2011
What’s so good about jQuery?
You’ve read that jQuery makes it easy to play with the DOM, add effects, and execute
Ajax requests.
Cross browsing
One of the biggest benefits of jQuery is that it handles a lot of infuriating cross-browser issues for you.
Support CSS3
jQuery also fully supports the upcoming CSS3 selector specification.
Utilities
Also included is an assortment of utility functions that implement common functions useful for writing jQuery (or are missing from JavaScript!): string trimming, the ability to easily extend objects, and more.
Support() function
One noteworthy utility is the supports function, which tests to find certain features are available on the current user’s browser
Widgets and Effects
JQuery has already been used to make some impressive widgets and effects.
Plugin
The jQuery team has taken great care in making the jQuery library extensible. By including only a core set of features while providing a framework for extending the library, they’ve made it easy to create plugins that you can reuse in all your jQuery projects, as well as share with other developers.
Clean markup
jQuery makes it a cinch to completely rid your markup of inline scripting, thanks to its ability to easily hook elements on the page and attach code to them in a natural
Ajax requests.
Cross browsing
One of the biggest benefits of jQuery is that it handles a lot of infuriating cross-browser issues for you.
Support CSS3
jQuery also fully supports the upcoming CSS3 selector specification.
Utilities
Also included is an assortment of utility functions that implement common functions useful for writing jQuery (or are missing from JavaScript!): string trimming, the ability to easily extend objects, and more.
Support() function
One noteworthy utility is the supports function, which tests to find certain features are available on the current user’s browser
Widgets and Effects
JQuery has already been used to make some impressive widgets and effects.
Plugin
The jQuery team has taken great care in making the jQuery library extensible. By including only a core set of features while providing a framework for extending the library, they’ve made it easy to create plugins that you can reuse in all your jQuery projects, as well as share with other developers.
Clean markup
jQuery makes it a cinch to completely rid your markup of inline scripting, thanks to its ability to easily hook elements on the page and attach code to them in a natural
The architecture of Linux
Linux consists of a central set of programs that run the PC on a low level, referred to as the kernel, and hundreds (if not thousands) of additional programs provided by other people and various companies. Technically speaking, the word Linux refers explicitly just to the core kernel program. However, most peoplegenerally refer to the entire bundle of programs that make up the operating system as Linux.
Although most of us refer to Linux as a complete operating system, the title “Linux” hides a lot of confusing
but rather important details. Technically speaking, the word Linux refers merely to the kernel file: the central
set of programs that lie at the heart of the operating system. Everything else that comes with a typical ver-
sion of Linux, such as programs to display graphics on the screen or let the user input data, is supplied by
other people, organizations, or companies. The Linux operating system is the combination of many disparate
projects.
The GNU organization, in particular, supplies a lot of vital programs and also system library files, without
which Linux wouldn’t run. These programs and files were vital to the acceptance of Linux as an operating
system in its early days. Because of this, and the fact that Linux completed a long-running goal of the GNU
project to create a Unix-like operating system, some people choose to refer to Linux as GNU/Linux.
Although most of us refer to Linux as a complete operating system, the title “Linux” hides a lot of confusing
but rather important details. Technically speaking, the word Linux refers merely to the kernel file: the central
set of programs that lie at the heart of the operating system. Everything else that comes with a typical ver-
sion of Linux, such as programs to display graphics on the screen or let the user input data, is supplied by
other people, organizations, or companies. The Linux operating system is the combination of many disparate
projects.
The GNU organization, in particular, supplies a lot of vital programs and also system library files, without
which Linux wouldn’t run. These programs and files were vital to the acceptance of Linux as an operating
system in its early days. Because of this, and the fact that Linux completed a long-running goal of the GNU
project to create a Unix-like operating system, some people choose to refer to Linux as GNU/Linux.
Characteristics of Servlets
Java servlets are fundamental Java EE platform components that provide a request/response interface for both Web requests and other requests such as XML messages or file transfer functions.
Servlets Use the Request/ResponseModel
Java servlets are a request/response mechanism: a programming construct designed to respond to
a particular request with a dynamic response generated by the servlet’s specific Java implementation. Servlets may be used for many types of request/response scenarios, but they are most often employed in the creation of HyperText Transfer Protocol (HTTP) responses in a web application. In this role, servlets replace other HTTP request/response mechanisms such as Common Gateway Interface (CGI) scripts.
The simple request/response model becomes a little more complex once you add chaining and filtering capabilities to the servlet specification. Servlets may now participate in the overall request/response scenario in additional ways, either by preprocessing the request and passing it on to another servlet to create the response or by postprocessing the response before returning it to the client. Later in this chapter, we discuss servlet filtering as a mechanism for adding auditing, logging, and debugging logic to your web application.
Servlets Use the Request/ResponseModel
Java servlets are a request/response mechanism: a programming construct designed to respond to
a particular request with a dynamic response generated by the servlet’s specific Java implementation. Servlets may be used for many types of request/response scenarios, but they are most often employed in the creation of HyperText Transfer Protocol (HTTP) responses in a web application. In this role, servlets replace other HTTP request/response mechanisms such as Common Gateway Interface (CGI) scripts.
The simple request/response model becomes a little more complex once you add chaining and filtering capabilities to the servlet specification. Servlets may now participate in the overall request/response scenario in additional ways, either by preprocessing the request and passing it on to another servlet to create the response or by postprocessing the response before returning it to the client. Later in this chapter, we discuss servlet filtering as a mechanism for adding auditing, logging, and debugging logic to your web application.
Processes Supporting an Instance
A number of processes are associated with an instance and perform specific tasks for the instance.
Listener
The Listener is a process that listens on the network for requests coming in to an Oracle instance. AListener
process can support one or more Oracle instances. The Listener acts as the intermediary between user
requests from remote machines and the instance. The failure of the Listener will mean that the instance it
supports is not accessible by a remote client—such as any application that accesses the instance.
Background Processes
Awhole set of processes run in the background on an Oracle server, supporting the actions of the Oracle
instance. The main processes are listed here, with the standard acronyms of the processes in parentheses:
❑ Database Writer (DBWR). Writes data blocks from the database buffers, as described in the fol-
lowing section.
❑ Log Writer (LGWR). Writes redo log information from the redo log buffer in memory to the
redo log on disk.
❑ System Monitor (SMON). Monitors the health of all components of an Oracle instance, and
helps to recovery the database when it is restarted after a crash.
❑ Process Monitor (PMON). Watches individual user processes that access the Oracle instance
and cleans up any resources left behind by an abnormal termination of a user process.
❑ Archiver (ARC). Writes a copy of a filled redo log file to an archive location. An Oracle instance
can have up to 10 Archiver processes.
Listener
The Listener is a process that listens on the network for requests coming in to an Oracle instance. AListener
process can support one or more Oracle instances. The Listener acts as the intermediary between user
requests from remote machines and the instance. The failure of the Listener will mean that the instance it
supports is not accessible by a remote client—such as any application that accesses the instance.
Background Processes
Awhole set of processes run in the background on an Oracle server, supporting the actions of the Oracle
instance. The main processes are listed here, with the standard acronyms of the processes in parentheses:
❑ Database Writer (DBWR). Writes data blocks from the database buffers, as described in the fol-
lowing section.
❑ Log Writer (LGWR). Writes redo log information from the redo log buffer in memory to the
redo log on disk.
❑ System Monitor (SMON). Monitors the health of all components of an Oracle instance, and
helps to recovery the database when it is restarted after a crash.
❑ Process Monitor (PMON). Watches individual user processes that access the Oracle instance
and cleans up any resources left behind by an abnormal termination of a user process.
❑ Archiver (ARC). Writes a copy of a filled redo log file to an archive location. An Oracle instance
can have up to 10 Archiver processes.
Thursday, January 13, 2011
V
A/ Who will be affected most in case of food poisoning?
B/ Young children are especially vulnerable for that.
B/ Young children are especially vulnerable for that.
U
A/ Do we have any plan for these machines?
B/ Yes, I think we should utilize them instead of throwing them away.
B/ Yes, I think we should utilize them instead of throwing them away.
N
A/ How do the children show their affection to their mother?
B/ They nuzzle up against their mother.
B/ They nuzzle up against their mother.
J
A/ Oh sorry, I am not intentionally.
B/ Yeah, no need to justify yourself to me
A/Are you confident with your decision?
B/ Let 's see. My result will justify my decision.
B/ Yeah, no need to justify yourself to me
A/Are you confident with your decision?
B/ Let 's see. My result will justify my decision.
G
A/ Good morning guys
B/ Good morning teacher
A/ How is the end of the film?
B/ The bad guy gets shot.
B/ Good morning teacher
A/ How is the end of the film?
B/ The bad guy gets shot.
F
A/ Did you care much about punctuation?
B/ No, I am not fussy about that.
A/ What do you usually think about yourself?
B/ I always think about way to get rich, and not fussy about appearance.
B/ No, I am not fussy about that.
A/ What do you usually think about yourself?
B/ I always think about way to get rich, and not fussy about appearance.
Wednesday, January 12, 2011
The Instance
The Oracle instance is the collection of processes that handle requests from a client for a data.
An Oracle instance is either started as part of the process of booting a server or can be started explicitly
with commands. Although you start an instance with a single command, there are actually three distinct
steps in the startup process:
❑ Starting the instance process itself
❑ Mounting the database, which consists of opening the control files for the instance
❑ Opening the database, which makes the database available for user requests
An instance can be stopped with another command or via the system console, which follows the same
sequence of events in reverse. You can stop an instance gracefully by stopping users from logging on to
the database and only shutting down when the last active user has logged off, or you can simply stop the instance, which may result in incomplete transactions.
An Oracle instance is either started as part of the process of booting a server or can be started explicitly
with commands. Although you start an instance with a single command, there are actually three distinct
steps in the startup process:
❑ Starting the instance process itself
❑ Mounting the database, which consists of opening the control files for the instance
❑ Opening the database, which makes the database available for user requests
An instance can be stopped with another command or via the system console, which follows the same
sequence of events in reverse. You can stop an instance gracefully by stopping users from logging on to
the database and only shutting down when the last active user has logged off, or you can simply stop the instance, which may result in incomplete transactions.
Architecture
The Oracle database consists of two main parts: the instance, which is the software service that acts as an
intermediary between application requests and its data, and the actual data files, which are where the data is
kept. The instance is a dynamic process and uses a variety of tasks and memory to support its operations. The data files are stored on disk, so the data itself will survive most service interruptions, except for catastrophic media failure.
intermediary between application requests and its data, and the actual data files, which are where the data is
kept. The instance is a dynamic process and uses a variety of tasks and memory to support its operations. The data files are stored on disk, so the data itself will survive most service interruptions, except for catastrophic media failure.
D
A/ Are you lazy at work?
B/ Absolutely not, I am very dynamic.
A/ Do you think that the group dynamics will change according to the company 's policy?
B/ Sure
B/ Absolutely not, I am very dynamic.
A/ Do you think that the group dynamics will change according to the company 's policy?
B/ Sure
C
A/ What is the most famous kind of sport in your hometown?
B/ Probably cycling. Lots of teenagers ride bicycle in my hometown.
B/ Probably cycling. Lots of teenagers ride bicycle in my hometown.
B
A/ Are you busy now?
B/Sorry, I have some urgent tasks. Bye for now.
A/ What did you do before leaving home to hcm city?
B/ I waved bye-bye my family and got into the car.
B/Sorry, I have some urgent tasks. Bye for now.
A/ What did you do before leaving home to hcm city?
B/ I waved bye-bye my family and got into the car.
A
A/ So what happen later?
B/ The room 's atmosphere is covered with awkward silence.
A/ Do you like to have salary increased?
B/ Oh no, Dont ask me such awkward question.
B/ The room 's atmosphere is covered with awkward silence.
A/ Do you like to have salary increased?
B/ Oh no, Dont ask me such awkward question.
T
A/ Do you know any theatre in HCM?
B/ Yes, Phu Nhuan theatre is my favourite one.
A/ Do you like music?
B/ No, I like cinema and theatre
A/ Do you like to work in theatre?
B/ No,I want to be a film actor
A/ Have you heard about the car theft in our neighbourhood?
B/ Yes, and I know that the police is investigating.
B/ Yes, Phu Nhuan theatre is my favourite one.
A/ Do you like music?
B/ No, I like cinema and theatre
A/ Do you like to work in theatre?
B/ No,I want to be a film actor
A/ Have you heard about the car theft in our neighbourhood?
B/ Yes, and I know that the police is investigating.
Tuesday, January 11, 2011
Files Used in the Startup Process
Note %systemroot% represents the path of your Windows XP Professional installation directory, which by default is a folder named \Windows on the system partition.
I want to change my work
Actually, my current project is not bad. It covers many knowledges in JEE. But my task is not interesting. Everyday I come to office and try to fix bug as much as possible. My team leader did not give me a good impression. Luckily, he will quit job lately this month. I prefer to speaking english and coding rather than fixing bugs. In the worst case, I will study MSCA and find another job. Hope It will be better tomorrow...
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