Precautions for obtaining varchar/nvarchar data in the database

When you obtain the data of a field in the database table in the background of the page, pay attention to the data type. It prevents space placeholders because the character length of the actual data cannot reach the character length specified by the specified data type.

For example:

The structure of a table in MSSQL is as follows:

Table data:

When a user name or password (userPwd) is obtained from the table, if the retrieved data is judged as a condition, it is best to Trim () the data obtained, remove space placeholders on both sides of the data

For example:

Before Trim () is processed, the data obtained from the database is subject to space placeholders due to insufficient data length.

 

After Trim () processing data, the placeholder is cleared.