Error map
ActiveRecord::RecordNotUnique: duplicate key value Rails: ActiveRecord::RecordNotUnique: PG::UniqueViolation: ERROR: duplicate key value violates unique constraint "index_users_on_email"
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 1062 (23000): Duplicate entry for key
An INSERT/UPDATE would create a duplicate value in a PRIMARY or UNIQUE key.
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: there is no unique or exclusion constraint matching the ON CONFLICT specification
INSERT … ON CONFLICT (cols) names columns that don’t have a matching unique index/constraint.
ERROR: insert or update on table "x" violates foreign key constraint "fk" — Key (user_id)=(5) is not present in table "users"
The row references a parent row that doesn’t exist.
ERROR: null value in column "x" of relation "y" violates not-null constraint
An INSERT/UPDATE put NULL into a NOT NULL column.
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.
ERROR: update or delete on table "users" violates foreign key constraint on table "orders" — Key (id)=(5) is still referenced
You tried to delete a row that other rows still reference.
ERROR: new row for relation "x" violates check constraint "y"
A value failed a CHECK constraint (e.g. price > 0, status IN (…)).
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 1451 (23000): Cannot delete or update a parent row: a foreign key constraint fails
You tried to delete/update a row that other rows still reference.
MongoServerError: E11000 duplicate key error collection: db.users index: email_1 dup key
An insert/update violated a unique index in MongoDB.
MySQL ERROR 1048 (23000): Column 'x' cannot be null
An INSERT/UPDATE put NULL into a NOT NULL column.
Two steps away (30)
Deadlock found when trying to get lock; try restarting transaction
Two transactions waited on each other’s locks; the database killed one so the other could continue.
HTTP 409 Conflict
The request conflicts with the current state of the resource — e.g. a duplicate or an edit based on an outdated version.
Subquery returns more than 1 row (MySQL 1242) / more than one row returned by a subquery used as an expression
A subquery used where a single value is expected (`= (SELECT …)`) returned several rows.
org.hibernate.exception.ConstraintViolationException: could not execute statement
The database rejected an insert/update because of a constraint (unique, foreign key, not null).
PrismaClientKnownRequestError P2002: Unique constraint failed on the fields: (`email`)
A Prisma create/update violated a unique constraint.
ERROR: currval of sequence "x" is not yet defined in this session
currval() was called before nextval() in the same session.
MySQL ERROR 1093 (HY000): You can't specify target table 'x' for update in FROM clause
An UPDATE/DELETE uses a subquery that reads from the same table, which MySQL doesn’t allow directly.
MySQL ERROR 1175 (HY000): You are using safe update mode and you tried to update a table without a WHERE that uses a KEY column
MySQL Workbench’s safe updates mode blocked an UPDATE/DELETE without a key-based WHERE.
ERROR: bind message supplies 2 parameters, but prepared statement requires 1
The number of query parameters sent doesn’t match the $1, $2 … placeholders in the SQL.
API Error: Resource already exists (ALREADY_EXISTS / resource_already_exists / 409)
The create request was refused because an object with the same unique identity — name, email, external ID — already exists.
DbUpdateException: An error occurred while saving the entity changes. See the inner exception for details.
SaveChanges failed in the database; the inner exception (SqlException/PostgresException) has the real reason — constraint violati…
ERROR: invalid input syntax for type integer: "abc"
A string couldn’t be converted to the column’s type (integer, numeric, boolean, date…).
ERROR: invalid input syntax for type uuid: "x"
A value that isn’t a valid UUID was compared with or inserted into a uuid column.
sqlite3.IntegrityError: NOT NULL constraint failed: table.column
A NULL went into a NOT NULL column in SQLite.
MySQL ERROR 1146 (42S02): Table 'db.table' doesn't exist
The query references a table that MySQL can’t find in that database.
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 1215 (HY000): Cannot add foreign key constraint
The foreign key can’t be created — mismatched column types, missing index, or incompatible engines/collations.
API Error: Invalid type — expected integer, received string
A request field has the wrong data type — a string where the API expects a number, a number where it expects a boolean, an object…
API Error: Invalid parameter value — must be one of the allowed values / out of range
The field has the right type but a value the API doesn’t allow — not in the list of accepted options, too small or large, too lon…
API Error: Invalid date format — expected ISO 8601 (YYYY-MM-DDTHH:mm:ssZ)
A date or timestamp in the request isn’t in the format the API expects — usually ISO 8601 with a time zone, or a Unix timestamp.
MySQL ERROR 1051 (42S02): Unknown table 'x'
DROP TABLE targeted a table that doesn’t exist.
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.
MySQL ERROR 1061 (42000): Duplicate key name 'x'
CREATE INDEX/ADD INDEX used an index name that already exists on the table.
Laravel: SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry 'x@example.com' for key 'users_email_unique'
The query violated a database constraint — a duplicate value in a unique column or a missing/blocked foreign key.
MongooseError: Operation `users.find()` buffering timed out after 10000ms
Mongoose queued a query waiting for a connection that never opened.
MongooseServerSelectionError: connect ECONNREFUSED 127.0.0.1:27017
The MongoDB driver couldn’t find a reachable server for the connection string.
CastError: Cast to ObjectId failed for value "x" (type string) at path "_id"
A value that isn’t a valid 24-hex-character ObjectId was used in an _id query.
HTTP 422 Unprocessable Content
The request is well-formed, but the data fails validation (e.g. invalid email, missing required field).
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…
java.lang.IllegalArgumentException
A method rejected an argument value as invalid.
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