Why Does Using Quotation Marks Around Table Names in Oracle Cause 'table or view does not exist' Errors?

Double quotes in Oracle database table names: interpreting case sensitivity

In Oracle, queries like SELECT * FROM site WHERE site_id = 3 work fine. However, if you add double quotes around the table name, such as SELECT * FROM "site" WHERE site_id = 3, it will result in a "table or view does not exist" error. This article explores the reasons behind this difference.

Double quotes and case sensitivity

In Oracle, adding double quotes to an identifier causes Oracle to treat the identifier as case-sensitive, rather than using the default case-insensitive manner. If you create a table (or column) using double quotes, you must always quote the identifier using double quotes, with the case specified correctly (except for all uppercase identifiers, in which case double quotes have no effect).

Internal handling of identifiers

Internally, Oracle always matches identifiers case-sensitively. However, it converts identifiers not enclosed in double quotes to uppercase before matching. If you use double quotes around the identifier, Oracle will skip the conversion to uppercase.

Summary

So always remember case sensitivity when using double quotes around table names. Identifiers that use double quotes must be quoted in double quotes and use the correct case. This ensures that database queries execute as expected, avoiding errors such as "table or view does not exist".

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