Common methods of SQL escaping in Oracle

What is Oracle SQL escaping?

In Oracle SQL, escaping refers to using some special characters or syntax to insert or access some special characters or symbols. Doing this avoids syntax errors in SQL statements, while also helping to prevent attacks on the database.

Common methods of SQL escaping in Oracle

1. Use single quotes to escape:

In SQL statements, we often need to use single quotes (') to include String type information, date type information, and even some special characters. If you are not careful enough in writing, you may cause SQL syntax errors, such as:

select * from users where name = 'john'smith';

This statement contains a single quote, and This single quote is not used to wrap string information, so there will be a syntax error. In this case, we can use the single quote escape character '' instead of a single quote:

select * from users where name = 'john''smith';

This way Grammar errors can be avoided.

2. Use double quotes to escape:

Another common escaping method is to use double quotes ("). Similar to single quote escaping, if we need it in a SQL statement Including another double quote, for example:

select * from users where name = "john"smith";

will also cause a syntax error. At this time, we can use the double quote escape character "" to replace a double quote:

select * from users where name = "john""smith";

3. Use backslash Slash escape:

In addition to single quote escape and double quote escape, there is another common escape method in Oracle SQL, which is to use backslash (\) to escape. In the SQL statement, if we need to include some special characters, such as line feeds, tabs, and carriage returns, we need to use backslash escape:

insert into users (name, info) values ​​( 'john', 'this is \

                                      a test');

In the above example, we used backslashes to display the information in separate lines.

Summary

In Oracle SQL, Escape is to avoid grammatical errors caused by special characters in SQL statements. Common escaping methods include single quote escape, double quote escape and backslash escape. Proficiency in Oracle SQL escape methods can help us be more precise. Write SQL statements efficiently and also improve the security of SQL.

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