How Do I Fix Case-Sensitivity Issues with Imported Tables in PostgreSQL?

PostgreSQL case sensitivity: resolving ambiguities in import tables

In PostgreSQL, the handling of case sensitivity can cause confusion when importing tables from other database systems (such as MSSQL Server 2008). When creating tables and columns in PostgreSQL, unquoted names are not case-sensitive, while quoted names are case-sensitive.

However, when importing tables from MSSQL Server, the import tool may create table and column names in all uppercase letters, resulting in case-sensitive names. This may cause errors when trying to access these tables, as Postgres's default case-insensitivity may not recognize uppercase names.

For example, if you try to create a data view on a table named "STD_TYPE_CODES" using the following query:

<code class="language-sql">select * from STD_TYPE_CODES</code>

You may receive an error indicating that the relationship 'std_type_codes' does not exist. This is because Postgres automatically converts unquoted table names to lowercase, causing a mismatch between the expected "STD_TYPE_CODES" and actual "std_type_codes" table names created during the import process.

In order to solve this problem, you can choose the following two methods:

1. Use quoted names : To ensure that the case-sensitive name of a table is recognized, you can enclose it in double quotes. For example:

<code class="language-sql">select * from "STD_TYPE_CODES"</code>

2. Convert table names to lowercase: You can use the ALTER TABLE command to convert existing table names to lowercase:

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

By converting table names to lowercase, you ensure compatibility with Postgres' default case-insensitive behavior. Alternatively, you can modify the dump file from MSSQL to make it compatible with Postgres by replacing all uppercase quoted names with lowercase quoted names.

To avoid similar problems in the future, it is recommended to use unquoted names or lowercase quoted names when creating tables and other objects in PostgreSQL. This will ensure that the case sensitivity of the name does not affect the accessibility of the data.

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