SQL, ( Structured Query Language )

What is SQL?

The Structured Query Language is used in manipulating data stored in Relational Database Management Systems (RDBMS). SQL provides commands through which data can be extracted, sorted, updated, deleted and inserted. SQL has the full support of ANSI (American National Standards Institute), which has laid down certain rules for the language.
SQL can be used with any RDBMS such as MySQL, mSQL, PostgresSQL, Oracle, Microsoft SQL Server, Access, Sybase, Ingres etc. All the important and common SQL statements are supported by these RDBMS, however, each has its own set of proprietary statements and extensions.

The SQL tutorial on webdevelopersnotes.com

As I mentioned before, SQL is a general query language for several different kinds of databases. The SQl tutorial on this site is has been built around MySQL, which is a open source RDBMS available for download at MySQL.com. However, I have tried to avoid the commands specific to MySQL in this SQL tutorial. The SQL tutorial would help build a strong foundation in the SQL language and you can then port your knowledge to the specific RDBMS you plan to use.

Why MySQL?

Choosing a database system depends on three main factors; the platform on which you work, your finances and what you want to achieve. The reason I chose MySQL is because, I work mostly on the Linux system and MySQL is free for Linux. Also, I am an ardent supporter of Open Source Software movement and firmly believe that the combination of Linux, Apache, MySQL and PHP (LAMP) is hard to beat.

What are databases and why do we need them?

In simplest terms, databases are store houses of data. Suppose you have an ASCII file that contains the names of your friends and their email addresses. Would you consider this file as a database? Technically, yes! You can add, update and delete data from this file. You may also write a small program (say in Perl or C) to extract, sort and display data on the basis of some search criterion.
The need to store data is quite a fundamental to humans. Data storage and representation has been with us for thousands of years. Take the example of cave drawings (graphical data) or charting the course of seasons over the years (this would have helped in knowing the best times to sow or to migrate). Collecting data is important but more significant is the analysis of the data. A case in point is study of the movements of astronomical objects (stars, planets, the moon and the sun). Analysis of this data gave birth to two sciences, Astronomy and Astrology. Astonomy helps us predict tides, eclipses etc. Astrology on the other hand had provided loads of entertainment (!) to avid followers over the years.
Coming back to the topic at hand, storing data is of prime importance because we can then analyse the data and extract some Information.

Tutorial TCP Mapping dgn Linux

Sebelumnya saya terbiasa menggunakan WinGATE untuk melakukan tcp mapping, yaitu mengalihkan routing yang meminta paket dari port tertentu. Misalnya klien membutuhkan akses ke sebuah IP (contoh: 202.0.0.1 port 22) yang berada di luar jangkauan si klien, tentunya hal tersebut dapat dipenuhi apabila ROUTER yang menjembatani antara 2 network tersebut dapat mengakses IP tujuan, caranya dengan men-set tcp mapping pada port tertentu misal (8000). Dengan konfigurasi tersebut klien hanya tinggal mengakses IP proxy dengan port 8000 maka ROUTER akan meneruskan paket tersebut ke IP 202.0.0.1 port 22.

Dengan metoda yang sama dapat juga dilakukan dengan linux:

iptables -t nat -A PREROUTING -i eth0 -p tcp –dport 8000 -j DNAT –to 202.0.0.1:22
iptables -t nat -A POSTROUTING -o eth0 -p tcp -s 202.0.0.1 –dport 22 -j SNAT –to 10.1.1.1:8000
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE

Sql Tuning

Companies that rely upon database information obtained by SQL queries commonly encounter performance issues as their databases grow to contain mass amounts of information. Over time, the same processes that have historically proven successful may become inadequate when the application needs to accommodate thousands or millions of database records. Suppose a company has always utilized a process in which a SQL query looks for a name by checking the first row to see if it holds the specified name, and if not, checking the second row for the name, and so on. When this company’s database held only fifty names, this method would have been perfectly efficient and acceptable. But how would the same query go about locating the same name once the company’s database has expanded to contain a thousand names? What about twenty million? The query would use the same system and likely get the job done, but not very efficiently. The CPU usage and response time would be compromised as the query was forced to navigate through mass amounts of information seeking one single record.

Database expansion poses challenges to developers and business owners whose profitability relies on optimal software performance. When an indefinite amount of information is expected to be added to a database, it becomes apparent that fine tuned SQL statements are necessary to minimize CPU usage and response time, which is where SQL tuning comes in.

SQL tuning involves streamlining the process through which SQL queries locate the sought after information. Innovative enterprise data availability companies have developed software solutions with extensive capabilities which help analyze the performance of the code and automate the process of identifying the specific applications that are causing performance delays, with the goal of reducing the time and CPU usage required to implement a new application. Such technology allows developers to analyze, test and correct the performance of new or existing applications in a test environment without affecting production. Such technology also allows developers to identify what specific issues are having the greatest effect on performance, so that they may focus their energy on correcting the problems with the highest priority.

SQL tuning technology targets and significantly improves the performance of SQL applications, in turn increasing QA production and reducing the need for time-consuming manual testing. It also provides developers with a tool to help analyze and maximize the efficiency of their applications during development, thus increasing productivity as well as enhancing the quality of their work.

Tiga Cara Memperindah Dokumen dengan CSS

Terdapat 3 cara untuk menempatkan CSS pada halaman web, inline, embedded, dan linked dari CSS style sheet yang terpisah. Satu-satunya yang sangat membuat pengaruh dalam pengembangan website adalah dengan membuat link ke halaman XHTML dengan sebuah CSS style sheet, namun kita akan pelajari dua cara lainnya juga, untuk mengetahui seberapa berguna 2 cara itu dalam pengembangan website.

Sebuah style sheet merupakan file yang terpisah seluruhnya dari file XHTML, dan hanya berisi CSS. Sebuah style sheet dapat di-share oleh halaman XHTML tanpa batas, yang dapat membantu untuk memastikan tampilan yang konsisten dari satu halaman ke halaman website lainnya dan dapat di-edit sebuah style secara instan dan langsung berpengaruh ke semua halaman web yang menggunakan style sheet yang diubah.

Create Account Blogger

Buka www.blogger.com Klik CIPTAKAN BLOG ANDA . . . .
Isikan semua form dengan benar, Contoh Alamat email : bd_maryanto
Seteleh selesai pengisian klik LANJUTKAN
Pengaturan Blog
Berikan Judul untuk Blog anda , contoh : artikel seribu
Buat alamat blog anda contoh : artikel1000
Klik LANJUTKAN
Jika muncul gambar seperti ini maka anda harus mengganti alamat blog, karena alamat blog tersebut telah dipergunakan orang lain
Pemilihan Template
Pilihlah salah satu template
Klik LANJUTKAN
Account Blogger Sudah Berhasil di Buat
Klik MULAI POSTING untuk melakukan posting
HALAMAN POSTING

Masukan atikel kedalam kotak “compose”, setelah selesai klik “Mempublikasikan Posting”
Jika anda sudah logout atau belum login untuk bisa memposting anda harus login terlebih dahulu, caranya
- buka blogger anda” misalnya http://artikel1000.blogspot.com (untuk account blogger domainnya dinamakan “blogspot”) lalu klik menu masuk di pojok kanan atas.
- isi username dan password anda
- klik post
MEMASANG GOOGLE ADSENSE
Untuk bisa memasang google adsense maka pengaturan bahasa pada blogger anda harus bahasa inggris(ada di pengaturan > format > bahasa).
Pilih template
Klik tambahkan sebuah elemen halaman
Maka akan muncul sebuah jendela pop up, seperti

Klik “TAMBAHKAN KE BLOG” pada bagian AdSense, jika baru pertama kali login pada google adsense pada blogger maka anda diminta untuk memasukan email account di google adsense dank ode pos atau 5 digit nomor telepon anda. Jika sudah login maka akan tampil seperti ini

Format: untuk mengatur ukuran google adsense
Warna : untuk mangatur warna² apa saja yang dipakai( disarankan untuk memakai “Padukan Template”)
Kostumisasi warna: dipakai jika anda tidak puas pada pilihan warna
Pratinjau : tampilan google adsense anda.
Klik SIMPAN PERUBAHAN jika anda sudah merasa puas

Element halaman tersebut bisa di geser² dengan cara klik bagian pinggir pada element lalu tahan mouse anda, geser ke tempat yang anda inginkan.
Setelah selesai klik simpan