How to solve garbled characters in Oracle

When using Oracle database, we often encounter the problem of garbled characters. This is because the Oracle database supports different encodings of characters, and garbled characters will occur when encodings are inconsistent. In order to solve this problem, we need to understand some knowledge about Oracle character encoding.

1. Introduction to Oracle character encoding

There are two types of character sets supported in Oracle database: single-byte character sets and multi-byte character sets. Among them, the single-byte character set has only one byte and can represent 256 characters, such as US7ASCII, WE8ISO8859P1; a multi-byte character set may consist of two or more bytes, such as UTF8, AL32UTF8, etc.

US7ASCII: American standard ASCII encoding, only supports English, numbers, and punctuation.

WE8ISO8859P1: ISO-8859-1 Latin1 encoding, supports characters in most European languages.

UTF8, AL32UTF8: Unicode character encoding, supporting characters worldwide.

2. Reasons for Oracle character garbled characters

1. Inconsistent character set

When storing data, if the character set used by the client is inconsistent with the database, then This will cause the data to appear garbled. For example, when the database uses the UTF8 character set and the client uses the GBK character set, the data stored in the database will not be displayed correctly.

2. Character set conversion error

During character set conversion, if the source character set is not converted into the target character set, the data will be garbled. For example, when exporting data from an AL32UTF8 database in Oracle 10g, the data needs to be exported to UTF-8 format. If the character set is not converted correctly, the exported data will not display correctly.

3. How to solve the problem of garbled characters in Oracle

1. Uniform character set

In order to avoid the problem of garbled characters, we should use the same character set uniformly . If you need to import data into a database, you should use the same character set as the database.

2. Modify the database character set

During the database installation process, you can choose a different default character set. If the database has been installed, you can modify the database character set by modifying the NLS_CHARACTERSET parameter. It should be noted that modifying the character set will cause all database data to be re-stored, so you need to back up the data before modifying it.

3. Use the character set conversion tool

If there is already garbled data, you can use the character set conversion tool to solve it. Commonly used tools include iconv, recode, nkf, etc.

4. Summary

Character set inconsistency and character set conversion errors are the main reasons for garbled characters in Oracle database. Only by unifying the character set, modifying the database character set and using character set conversion tools can this problem be effectively solved. When using Oracle database, we need to pay attention to the choice of character set and the correct application of character set conversion.

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