oracle import garbled code

Oracle database is a relational database management system that is currently widely used. During use, garbled characters may be imported due to environment, encoding and other reasons. This article will introduce the reasons, solutions and related precautions for Oracle importing garbled characters.

1. Reasons for importing garbled characters

1. Character sets are inconsistent. When the character set of the database is inconsistent with the character set of the data source, garbled characters may occur during import. For example, if the database is a UTF-8 character set and the data source is a GBK character set, garbled characters will appear when the data is imported.
2. The data source itself is garbled. When the data source itself is garbled, garbled characters will also appear when importing.
3. The character set is not set when importing. If the character set is not specified when importing, the character set may be inconsistent, resulting in garbled characters.

2. Solution

1. Set the database character set. First, you need to confirm that the database character set is consistent with the data source. You can check the database character set through the following steps:

(1) After connecting to the database using SQLPLUS, enter SELECT * FROM NLS_DATABASE_PARAMETERS;

(2) Check the NLS_CHARACTERSET parameter value, if it matches If the data source character set is consistent, the import operation can be performed.

If the database character set is inconsistent with the data source character set, you need to first convert the database character set to be consistent with the data source character set and confirm whether it affects the data of other tables. You can use the ALTER DATABASE CHARACTER SET command provided by Oracle during conversion.

2. Set the client character set. When importing data, you need to set the corresponding character set on the client. It can be set by the following command:

(1) Taking sqlplus as an example, set the character set to UTF-8:

set NLS_LANG=utf8

(2) Taking PL/SQL Developer as an example, open "Tools"->"Preferences" in the menu and set the "NLS_LANG" parameter in "Environment".

3. Set the character set when importing. When using the Oracle import tool, you need to specify the corresponding character set. For example, when using the imp command to import data, you can use the following parameters:

imp userid=user/password file=myfile.dmp fromuser=from_user touser=to_user commit=y feedback=1000000 buffer=30720 ignore=y constraints=y grants=y indexes=y rows=y consistent=y statistics=none recordlength=65535 log=mylog.log _bigfile_threshold=0.0 ignore=y file_encoding=UTF8

The file_encoding parameter specifies the character set of the data source file.

3. Precautions

1. When performing character set conversion, the data needs to be backed up to avoid data loss caused by improper operation.
2. When importing, you need to ensure that the character set of the data source file is consistent with the character set of the server, otherwise garbled characters may appear even if the character set is set.
3. Setting the character set when importing needs to be set in the correct location, otherwise it may be invalid.
4. When dealing with garbled characters, you need to understand the corresponding character set and encoding knowledge in order to better solve the problem.

To sum up, when garbled characters occur when importing data into the Oracle database, we need to carefully analyze the cause of the problem and adopt corresponding solutions to solve the problem. Successful data import can only be ensured with the correct environment and settings.

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