Multiple choice technology databases

Which of the following can be a valid column name?

  1. Column

  2. 1966_Invoices

  3. #Invoices

  4. Catch_#22
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In Oracle SQL (and most databases), unquoted column names must start with a letter, not a number. '1966_Invoices' starts with a number making it invalid. '#Invoices' starts with a special character. 'Catch_#22' is valid because it starts with a letter and contains only allowed characters (letters, digits, underscore, hash). 'Column' may be a reserved keyword but can be used as a column name without quoting in Oracle.

AI explanation

To answer this question, we need to understand the rules for valid column names in databases.

In most databases, including SQL, column names must adhere to the following rules:

  1. Column names can contain letters (A-Z, a-z), numbers (0-9), and underscores (_).
  2. Column names cannot start with a number.
  3. Column names cannot contain special characters like spaces, symbols, or punctuation marks except for underscores (_).
  4. Column names are case-insensitive, meaning "Column" and "column" are considered the same.

Let's go through each option to determine if it is a valid column name:

A. Column - This option is valid because it only contains letters and does not violate any of the rules mentioned above.

B. 1966_Invoices - This option is valid because it contains letters, numbers, and underscores. However, it starts with a number, which violates the second rule. Therefore, this option is not a valid column name.

C. #Invoices - This option is not valid because it contains a special character (#) that is not allowed in column names.

D. Catch_#22 - This option is valid because it contains letters, numbers, and underscores. It does not violate any of the rules mentioned above. Therefore, this option is a valid column name.

Based on the above analysis, the correct answer is D. Catch_#22, as it follows all the rules for a valid column name.

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