Sql error 42p01 error relation does not exist

PostgreSQL error 42P01 actually makes users dumbfounded, especially the newbies.

Usually, this error occurs due to an undefined table in newly created databases.

That’s why at Bobcares, we often get requests to fix PostgreSQL errors, as a part of our Server Management Services.

Today, let’s have a look into the PostgreSQL error 42P01 and see how our Support Engineers fix it.

What is PostgreSQL error 42P01?

PostgreSQL has a well-defined error code description. This helps in identifying the reason for the error.

Today, let’s discuss in detail about PostgreSQL error 42P01. The typical error code in PostgreSQL appears as:

ERROR: relation "[Table name]" does not exist

SQL state:42P01

Here the 42P01 denotes an undefined table.

So, the code description clearly specifies the basic reason for the error.

But what does an undefined table means?

Let’s discuss it in detail.

Causes and fixes for the PostgreSQL error 42P01

Customer query on undefined tables of a database often shows up the 42P01 error.

Now let’s see a few situations when our customers get the 42P01 error. We will also see how our Support Engineers fix this error.

1. Improper database setup

Newbies to Postgres often make mistakes while creating a new database. Mostly, this improper setup ends up in a 42P01 error.

In such situations, our Support Team guides them for easy database setup.

Firstly, we create a new database. Next, we create a new schema and role. We give proper privileges to tables.

Postgres also allows users to ALTER DEFAULT PRIVILEGES.

2. Unquoted identifiers

Some customers create tables with mixed-case letters.

Usually, the unquoted identifiers are folded into lowercase. So, when the customer queries the table name with the mixed case it shows 42P01 error.

The happens as the PostgreSQL has saved the table name in lower case.

To resolve this error, our Support Engineers give mixed case table name in quotes. Also, we highly recommend to NOT use quotes in database names. Thus it would make PostgreSQL behave non-case sensitive.

3. Database query on a non-public schema

Similarly, the PostgreSQL 42P01 error occurs when a user queries a non-public schema.

Usually, this error occurs if the user is unaware of the proper Postgres database query.

For instance, the customer query on table name ‘pgtable‘ was:

SELECT * FROM  pgtable

This query is totally correct in case of a public schema. But, for a non-public schema ‘xx’ the query must be:

SELECT * FROM  "xx"."pgtable"

Hence, our Support Engineers ensure that the query uses the correct schema name.

[Still having trouble in fixing PostgreSQL errors? – We’ll fix it for you.]

Conclusion

In short, PostgreSQL error 42P01 denotes the database query is on an undefined table. This error occurs due to improper database setup, unidentified table name, and so on. Today, we saw how our Support Engineers fix the undefined table error in Postgres.

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Easy fix for PostgreSQL error 42P01

by Keerthi PS | Sep 29, 2019

PostgreSQL error 42P01 actually makes users dumbfounded, especially the newbies.

Usually, this error occurs due to an undefined table in newly created databases.

That’s why at Bobcares, we often get requests to fix PostgreSQL errors, as a part of our Server Management Services.

Today, let’s have a look into the PostgreSQL error 42P01 and see how our Support Engineers fix it.

What is PostgreSQL error 42P01?

PostgreSQL has a well-defined error code description. This helps in identifying the reason for the error.

Today, let’s discuss in detail about PostgreSQL error 42P01. The typical error code in PostgreSQL appears as:

Here the 42P01 denotes an undefined table.

So, the code description clearly specifies the basic reason for the error.

But what does an undefined table means?

Let’s discuss it in detail.

Causes and fixes for the PostgreSQL error 42P01

Customer query on undefined tables of a database often shows up the 42P01 error.

Now let’s see a few situations when our customers get the 42P01 error. We will also see how our Support Engineers fix this error.

1. Improper database setup

Newbies to Postgres often make mistakes while creating a new database. Mostly, this improper setup ends up in a 42P01 error.

In such situations, our Support Team guides them for easy database setup.

Firstly, we create a new database. Next, we create a new schema and role. We give proper privileges to tables.

Postgres also allows users to ALTER DEFAULT PRIVILEGES.

2. Unquoted identifiers

Some customers create tables with mixed-case letters.

Usually, the unquoted identifiers are folded into lowercase. So, when the customer queries the table name with the mixed case it shows 42P01 error.

The happens as the PostgreSQL has saved the table name in lower case.

To resolve this error, our Support Engineers give mixed case table name in quotes. Also, we highly recommend to NOT use quotes in database names. Thus it would make PostgreSQL behave non-case sensitive.

3. Database query on a non-public schema

Similarly, the PostgreSQL 42P01 error occurs when a user queries a non-public schema.

Usually, this error occurs if the user is unaware of the proper Postgres database query.

For instance, the customer query on table name ‘pgtable‘ was:

This query is totally correct in case of a public schema. But, for a non-public schema ‘xx’ the query must be:

Hence, our Support Engineers ensure that the query uses the correct schema name.

[Still having trouble in fixing PostgreSQL errors? – We’ll fix it for you.]

Conclusion

In short, PostgreSQL error 42P01 denotes the database query is on an undefined table. This error occurs due to improper database setup, unidentified table name, and so on. Today, we saw how our Support Engineers fix the undefined table error in Postgres.

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Postgresql sql error 42p01

All messages emitted by the PostgreSQL server are assigned five-character error codes that follow the SQL standard’s conventions for “ SQLSTATE ” codes. Applications that need to know which error condition has occurred should usually test the error code, rather than looking at the textual error message. The error codes are less likely to change across PostgreSQL releases, and also are not subject to change due to localization of error messages. Note that some, but not all, of the error codes produced by PostgreSQL are defined by the SQL standard; some additional error codes for conditions not defined by the standard have been invented or borrowed from other databases.

According to the standard, the first two characters of an error code denote a class of errors, while the last three characters indicate a specific condition within that class. Thus, an application that does not recognize the specific error code might still be able to infer what to do from the error class.

Table A.1 lists all the error codes defined in PostgreSQL 15.0. (Some are not actually used at present, but are defined by the SQL standard.) The error classes are also shown. For each error class there is a “ standard ” error code having the last three characters 000 . This code is used only for error conditions that fall within the class but do not have any more-specific code assigned.

The symbol shown in the column “ Condition Name ” is the condition name to use in PL/pgSQL . Condition names can be written in either upper or lower case. (Note that PL/pgSQL does not recognize warning, as opposed to error, condition names; those are classes 00, 01, and 02.)

For some types of errors, the server reports the name of a database object (a table, table column, data type, or constraint) associated with the error; for example, the name of the unique constraint that caused a unique_violation error. Such names are supplied in separate fields of the error report message so that applications need not try to extract them from the possibly-localized human-readable text of the message. As of PostgreSQL 9.3, complete coverage for this feature exists only for errors in SQLSTATE class 23 (integrity constraint violation), but this is likely to be expanded in future.

Table A.1. PostgreSQL Error Codes

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