Chinese PRC Collation

Posted on 2008-11-04
Last Modified: 2008-11-16
I need my SQL Server 2005 to support Chinese characters. Under the setup, I could see serveral collation :


What is the difference between the collation ? What is the difference between var and nvar ? Should I use nvar to include double bytes chars ??

Many thanks
Question by:AXISHK
    LVL 12

    Accepted Solution

    For the collation (because i have came up to a similar situation with CHINESE encoding I suggest that you should consult your customers in order to inform you for the collect collation.
    If you chose a wrong collation don,t worry
    You can with script change the collation in all tables in your database
    The collation will "play" a significant role in your sorting, If you chose the wrong collation you may see the ORDER BY option not working correctly, actually it works correctly but depending on your collation the ORDER BY will short based on two bytes or one byte per character.

    I thing that nvarchar (generally all character fields that starts with "n") are Unicode. So in order to be sure that you are able to store all kind of data use "N" chars. Keep in mind that a VARCHAR may have
    up to 8000 characters but a NVARCHAR supports up to 4000. Two bytes per character.
    Below is help from microsoft

    (Microsoft Help)
    The Unicode specification defines a single encoding scheme for most characters widely used in businesses around the world. All computers consistently translate the bit patterns in Unicode data into characters using the single Unicode specification. This ensures that the same bit pattern is always converted to the same character on all computers. Data can be freely transferred from one database or computer to another without concern that the receiving system will translate the bit patterns into characters incorrectly.

    One problem with data types that use 1 byte to encode each character is that the data type can only represent 256 different characters. This forces multiple encoding specifications (or code pages) for different alphabets such as European alphabets, which are relatively small. It is also impossible to handle systems such as the Japanese Kanji or Korean Hangul alphabets that have thousands of characters.

    Each Microsoft® SQL Server" collation has a code page that defines what patterns of bits represent each character in char, varchar, and text values. Individual columns and character constants can be assigned a different code page. Client computers use the code page associated with the operating system locale to interpret character bit patterns. There are many different code pages. Some characters appear on some code pages, but not on others. Some characters are defined with one bit pattern on some code pages, and with a different bit pattern on other code pages. When you build international systems that must handle different languages, it becomes difficult to pick code pages for all the computers that meet the language requirements of multiple countries. It is also difficult to ensure that every computer performs the correct translations when interfacing with a system using a different code page.

    The Unicode specification addresses this problem by using 2 bytes to encode each character. There are enough different patterns (65,536) in 2 bytes for a single specification covering the most common business languages. Because all Unicode systems consistently use the same bit patterns to represent all characters, there is no problem with characters being converted incorrectly when moving from one system to another. You can minimize character conversion issues by using Unicode data types throughout your system.

    In Microsoft SQL Server, these data types support Unicode data:




    Note  The n prefix for these data types comes from the SQL-92 standard for National (Unicode) data types.

    Use of nchar, nvarchar, and ntext is the same as char, varchar, and text, respectively, except that:

    Unicode supports a wider range of characters.

    More space is needed to store Unicode characters.

    The maximum size of nchar and nvarchar columns is 4,000 characters, not 8,000 characters like char and varchar.

    Unicode constants are specified with a leading N: N'A Unicode string'.

    All Unicode data uses the same Unicode code page. Collations do not control the code page used for Unicode columns, only attributes such as comparison rules and case sensitivity.
    LVL 31

    Assisted Solution

    by:James Murrell

    Write Comment

    Please enter a first name

    Please enter a last name

    We will never share this with anyone.

    Featured Post

    Looking for New Ways to Advertise?

    Engage with tech pros in our community with native advertising, as a Vendor Expert, and more.

    Performance is the key factor for any successful data integration project, knowing the type of transformation that you’re using is the first step on optimizing the SSIS flow performance, by utilizing the correct transformation or the design alternat…
    When you hear the word proxy, you may become apprehensive. This article will help you to understand Proxy and when it is useful. Let's talk Proxy for SQL Server. (Not in terms of Internet access.) Typically, you'll run into this type of problem w…
    Familiarize people with the process of utilizing SQL Server functions from within Microsoft Access. Microsoft Access is a very powerful client/server development tool. One of the SQL Server objects that you can interact with from within Microsoft Ac…
    This video shows, step by step, how to configure Oracle Heterogeneous Services via the Generic Gateway Agent in order to make a connection from an Oracle session and access a remote SQL Server database table.

    737 members asked questions and received personalized solutions in the past 7 days.

    Join the community of 500,000 technology professionals and ask your questions.

    Join & Ask a Question

    Need Help in Real-Time?

    Connect with top rated Experts

    18 Experts available now in Live!

    Get 1:1 Help Now