How Does PostgreSQL Handle Case Sensitivity in Table Names?

PostgreSQL table name case sensitivity: handling case mismatch

When using PostgreSQL database, users may encounter inconsistent table access issues when migrating tables from other databases (such as MSSQL Server). A common problem arises from the case sensitivity of table names in PostgreSQL.

In PostgreSQL, unquoted table names are case-insensitive. This means that accessing a table named "STD_TYPE_CODES" is equivalent to "STD_TYPE_codes" or "std_type_codes". However, quoting the table name makes it case-sensitive, causing errors when accessing the table using different cases.

To solve this problem, there are several ways:

1. Use unquoted table names

To avoid case sensitivity issues, it is recommended to use unquoted names to create and access tables. This ensures that table names are treated as case-insensitive and match the expected case regardless of user input.

2. Consistently use quoted table names

If you use quoted table names, they must always be specified using correct case. For example, if a table was created as "STD_TYPE_CODES", accessing it must always use "STD_TYPE_CODES", not "std_type_codes" or "Std_Type_Codes".

3. Convert existing table

To fix an existing table with a case mismatch, use the ALTER TABLE command. For example, to convert table "FOO" to lowercase, use:

<code class="language-sql">ALTER TABLE "FOO" RENAME TO "foo"</code>

4. Modify database dump

When migrating tables from MSSQL Server to PostgreSQL, the database dump can be modified to ensure that table names are consistent with PostgreSQL's case sensitivity rules. This can be done by:

• Explicitly edit the dump file to convert all quoted table names to lowercase.
• Use options in MSSQL to generate dumps with lowercase or unquoted table names.

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