Error map
42P01 PostgreSQL: ERROR: relation "x" does not exist
PostgreSQL · layer 5, Data
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Directly related (12)
Rails: ActiveRecord::PendingMigrationError — Migrations are pending. To resolve this issue, run: bin/rails db:migrate
The database schema is behind the migration files in the app.
PostgreSQL: FATAL: password authentication failed for user
PostgreSQL rejected the password for that role, or pg_hba.conf requires a different auth method.
dotnet ef: Unable to create a 'DbContext' of type ''. The exception 'Unable to resolve service for type DbContextOptions' was thrown while attempting to create an instance
dotnet ef migrations couldn’t construct your DbContext at design time.
MongoDB: MongoServerError: Document failed validation (code 121)
The collection has a JSON Schema validator and the inserted/updated document doesn’t satisfy it.
SQL Server: Invalid object name 'x'. (Msg 208)
The table/view doesn’t exist in the current database or schema.
MySQL ERROR 1146 (42S02): Table 'db.table' doesn't exist
The query references a table that MySQL can’t find in that database.
PostgreSQL: ERROR: column "x" does not exist
PostgreSQL can’t find the column — a missing migration, a case-sensitive quoted name, or a string literal written in double quote…
ERROR: relation "x" already exists
CREATE TABLE/INDEX/SEQUENCE used a name that already exists in that schema.
django.db.utils.OperationalError: no such table: app_model
Django queried a table that hasn’t been created — migrations missing or not applied.
API Error: Request failed schema validation (must NOT have additional properties / Additional properties are not allowed)
The JSON body doesn’t match the endpoint’s schema — an unknown property, wrong nesting, or a missing required object.
MySQL ERROR 1060 (42S21): Duplicate column name 'x'
A CREATE/ALTER adds a column that already exists, or a SELECT in a view/derived table produces two columns with the same name.
ERROR: column "x" of relation "y" already exists
ALTER TABLE ADD COLUMN for a column that’s already there.
Two steps away (34)
MySQL ERROR 1022 (23000): Can't write; duplicate key in table
An ALTER/CREATE produced a duplicate key or constraint name — often a foreign key name that already exists in the database.
MySQL ERROR 1051 (42S02): Unknown table 'x'
DROP TABLE targeted a table that doesn’t exist.
MySQL ERROR 1061 (42000): Duplicate key name 'x'
CREATE INDEX/ADD INDEX used an index name that already exists on the table.
MySQL ERROR 1045 (28000): Access denied for user
MySQL rejected the login — wrong password, wrong user/host combination, or the user doesn’t exist.
PostgreSQL: could not connect to server / connection refused — Is the server running on host and accepting TCP/IP connections?
The client reached no PostgreSQL listener at that host/port — the server is down, listening elsewhere, or not accepting remote co…
PostgreSQL: ERROR: permission denied for table / schema public
The role is connected but lacks privileges on that table or schema — very common after PostgreSQL 15 removed CREATE on the public…
InvalidOperationException: Unable to resolve service for type 'X' while attempting to activate 'Y'
ASP.NET Core’s dependency injection container can’t build Y because one of its constructor dependencies (X) was never registered.
MySQL ERROR 1091 (42000): Can't DROP 'x'; check that column/key exists
ALTER TABLE tried to drop a column or index that doesn’t exist.
Laravel: SQLSTATE[42S02]: Base table or view not found: 1146 Table 'db.sessions' doesn't exist
Laravel queried a table that hasn’t been created — usually sessions, cache, jobs or a new model’s table.
MySQL ERROR 1054 (42S22): Unknown column in 'field list'
The query references a column that doesn’t exist in the table (or an unquoted string being read as a column).
HTTP 422 Unprocessable Content
The request is well-formed, but the data fails validation (e.g. invalid email, missing required field).
GraphQL: Cannot query field "x" on type "Y"
The query asks for a field that doesn’t exist in the server’s schema (or isn’t available on that type).
sqlite3.OperationalError: no such column: x
SQLite can’t find the column — missing migration, typo, or a string written in double quotes.
SQL Server: Invalid column name 'x'. (Msg 207)
SQL Server can’t find the column — typo, missing migration, or a string in double quotes with QUOTED_IDENTIFIER ON.
SQL Server: Conversion failed when converting the varchar value 'x' to data type int. (Msg 245)
SQL Server tried to convert text to a number (often implicitly) and hit a non-numeric value.
MySQL ERROR 1044 (42000): Access denied for user to database
The login succeeded, but the user has no privileges on the database you’re using.
MySQL ERROR 1064 (42000): You have an error in your SQL syntax
MySQL couldn’t parse the query. The text after “near” shows where parsing failed.
MySQL ERROR 1452: Cannot add or update a child row: a foreign key constraint fails
You inserted/updated a row whose foreign key value doesn’t exist in the referenced parent table.
Column reference is ambiguous / Column 'id' in field list is ambiguous (MySQL 1052)
A column name exists in more than one joined table, so the database doesn’t know which one you mean.
PostgreSQL: ERROR: duplicate key value violates unique constraint
An INSERT/UPDATE would create a duplicate in a UNIQUE or PRIMARY KEY column — or the id sequence is behind the existing data.
ERROR: syntax error at or near "x"
PostgreSQL couldn’t parse the SQL; the token shown is where parsing failed.
ERROR: cannot drop table x because other objects depend on it
Views, foreign keys or other objects depend on what you’re dropping.
Room cannot verify the data integrity. Looks like you've changed schema but forgot to update the version number
The Room entity definitions changed, but the database version wasn’t increased or no migration was provided.
django.core.exceptions.ImproperlyConfigured: settings are not configured / SECRET_KEY must not be empty
Django can’t load its settings — DJANGO_SETTINGS_MODULE unset, a required setting missing, or an environment variable not provide…
django.core.exceptions.DisallowedHost: Invalid HTTP_HOST header: 'x'. You may need to add 'x' to ALLOWED_HOSTS.
The request’s Host header isn’t listed in Django’s ALLOWED_HOSTS.
django.template.exceptions.TemplateDoesNotExist: app/page.html
Django searched all template directories and couldn’t find that template.
MySQL ERROR 1406: Data too long for column
The value is longer than the column allows (e.g. 300 characters into VARCHAR(255)), and strict mode rejects it instead of truncat…
MySQL ERROR 1005 (HY000): Can't create table (errno: 150 "Foreign key constraint is incorrectly formed")
A foreign key definition is invalid — the referenced column’s type, index or charset doesn’t match.
MySQL ERROR 1007 (HY000): Can't create database 'x'; database exists
CREATE DATABASE ran for a database that already exists.
MySQL ERROR 1008 (HY000): Can't drop database 'x'; database doesn't exist
DROP DATABASE targeted a database that isn’t there.
MySQL ERROR 1067 (42000): Invalid default value for 'created_at'
A column’s DEFAULT isn’t allowed in the current SQL mode — classically '0000-00-00 00:00:00' with NO_ZERO_DATE.
MySQL ERROR 1075 (42000): Incorrect table definition; there can be only one auto column and it must be defined as a key
An AUTO_INCREMENT column isn’t indexed (or there are two auto-increment columns).
ERROR: prepared statement "s1" already exists (PgBouncer transaction mode)
Named prepared statements collided — typically because PgBouncer in transaction pooling mode hands connections between clients.
ERROR: database "x" is being accessed by other users — There is 1 other session using the database.
DROP/RENAME DATABASE can’t run while other sessions are connected.
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