Error map
ActiveRecord::PendingMigrationError Rails: ActiveRecord::PendingMigrationError — Migrations are pending. To resolve this issue, run: bin/rails db:migrate
Ruby / Rails · layer 4, Application & API
Centre: this error. First ring: errors it is linked with (12). Outer ring: what those are linked with. Colours show the layer of a request each error belongs to. Click any dot to re-centre the map on it; hover to follow its connections. The centre dot opens the error page.
Directly related (12)
MySQL ERROR 1146 (42S02): Table 'db.table' doesn't exist
The query references a table that MySQL can’t find in that database.
django.db.utils.OperationalError: no such table: app_model
Django queried a table that hasn’t been created — migrations missing or not applied.
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.
sqlite3.OperationalError: no such column: x
SQLite can’t find the column — missing migration, typo, or a string written in double quotes.
PostgreSQL: ERROR: relation "x" does not exist
The table/view isn’t found — missing migration, wrong schema, or a case-sensitive quoted name.
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.
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 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.
ERROR: relation "x" already exists
CREATE TABLE/INDEX/SEQUENCE used a name that already exists in that schema.
ERROR: column "x" of relation "y" already exists
ALTER TABLE ADD COLUMN for a column that’s already there.
Two steps away (29)
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 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).
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.
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.
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.
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…
sqlite3.IntegrityError: FOREIGN KEY constraint failed
An insert/update/delete violated a foreign key in SQLite (with PRAGMA foreign_keys=ON).
sqlite3.OperationalError: attempt to write a readonly database
The process can’t write to the SQLite file or its directory.
PostgreSQL: FATAL: password authentication failed for user
PostgreSQL rejected the password for that role, or pg_hba.conf requires a different auth method.
ERROR: cannot drop table x because other objects depend on it
Views, foreign keys or other objects depend on what you’re dropping.
SQL Server: Invalid object name 'x'. (Msg 208)
The table/view doesn’t exist in the current database or schema.
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.
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.
InvalidOperationException: No database provider has been configured for this DbContext
EF Core created a DbContext without UseSqlServer/UseNpgsql/UseSqlite — typically because the context was newed up manually or reg…
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 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).
MySQL ERROR 1215 (HY000): Cannot add foreign key constraint
The foreign key can’t be created — mismatched column types, missing index, or incompatible engines/collations.
MySQL ERROR 1071 (42000): Specified key was too long; max key length is 767 bytes
An index on a VARCHAR is too long for the row format — classic with utf8mb4 VARCHAR(255) on MySQL 5.6/MariaDB 10.1.
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.
MongoDB: MongoServerError: Document failed validation (code 121)
The collection has a JSON Schema validator and the inserted/updated document doesn’t satisfy it.
Laravel: No application encryption key has been specified.
Laravel’s APP_KEY is missing, so it can’t encrypt sessions and cookies.
Laravel: 419 Page Expired (CSRF token mismatch)
Laravel rejected a POST because the CSRF token was missing, expired or didn’t match the session.
Laravel: Target class [App\Http\Controllers\X] does not exist.
Laravel’s container couldn’t find the controller or class named in a route or binding.
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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