Error map
DbUpdateException DbUpdateException: An error occurred while saving the entity changes. See the inner exception for details.
.NET · 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.
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.
ORA-00001: unique constraint (SCHEMA.PK_X) violated
An insert/update duplicated a value in a unique or primary key constraint.
EF Core: The entity type 'X' requires a primary key to be defined
EF Core found an entity class without a key property it can recognise.
ObjectDisposedException: Cannot access a disposed context instance
Code used a DbContext after its scope ended — usually async void, fire-and-forget tasks, or capturing a scoped context in a singl…
ERROR: null value in column "x" of relation "y" violates not-null constraint
An INSERT/UPDATE put NULL into a NOT NULL column.
sqlite3.IntegrityError: UNIQUE constraint failed: users.email
An insert/update duplicated a value in a UNIQUE or PRIMARY KEY column in SQLite.
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.
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.
sqlalchemy.exc.IntegrityError: (psycopg2.errors.UniqueViolation) duplicate key value violates unique constraint
A database constraint (unique, foreign key, not null) rejected an insert/update made through SQLAlchemy.
SQL Server: Violation of PRIMARY KEY constraint 'x'. Cannot insert duplicate key in object 'y'. (Msg 2627)
An insert duplicated a primary key or unique constraint value.
EF Core: A second operation was started on this context instance before a previous operation completed
The same DbContext was used concurrently — async calls not awaited, parallel tasks sharing a context, or a context registered as…
Two steps away (34)
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.
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.
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.
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.
sqlite3.IntegrityError: NOT NULL constraint failed: table.column
A NULL went into a NOT NULL column in SQLite.
ORA-00942: table or view does not exist
Oracle can’t see the table — it doesn’t exist, is in another schema, or you lack privileges on it.
ORA-00904: "X": invalid identifier
A column name in the statement doesn’t exist (or is misquoted).
JsonException: A possible object cycle was detected
System.Text.Json found a reference loop (e.g. Order → Customer → Orders → …) while serialising, usually from EF Core navigation p…
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…
The instance of entity type 'X' cannot be tracked because another instance with the same key value for {'Id'} is already being tracked
Two different objects with the same primary key were attached to one DbContext.
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.
EF Core: The LINQ expression 'x' could not be translated. Either rewrite the query in a form that can be translated, or switch to client evaluation explicitly
The query uses C# code EF Core can’t convert to SQL — custom methods, unsupported string/date functions, or complex projections.
HTTP Error 500.19 - Internal Server Error: The requested page cannot be accessed because the related configuration data for the page is invalid
IIS can’t read web.config — usually the ASP.NET Core Hosting Bundle (AspNetCoreModuleV2) or URL Rewrite module isn’t installed, o…
MySQL ERROR 1048 (23000): Column 'x' cannot be null
An INSERT/UPDATE put NULL into a NOT NULL column.
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 (…)).
sqlite3.OperationalError: attempt to write a readonly database
The process can’t write to the SQLite file or its directory.
ORA-01400: cannot insert NULL into ("SCHEMA"."TABLE"."COLUMN")
A NULL was inserted into a NOT NULL column.
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.
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: relation "x" does not exist
The table/view isn’t found — missing migration, wrong schema, or a case-sensitive quoted name.
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.
org.hibernate.LazyInitializationException: could not initialize proxy - no Session
A lazy-loaded association was accessed after the Hibernate session/transaction closed.
org.hibernate.TransientObjectException: object references an unsaved transient instance - save the transient instance before flushing
An entity references another entity that hasn’t been saved yet, and no cascade is configured.
org.hibernate.exception.ConstraintViolationException: could not execute statement
The database rejected an insert/update because of a constraint (unique, foreign key, not null).
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.
SQL Server: Arithmetic overflow error converting expression to data type int. (Msg 8115)
A value or calculation exceeds the target data type’s range.
SQL Server: Cannot insert explicit value for identity column in table 'x' when IDENTITY_INSERT is set to OFF.
An INSERT supplied a value for an IDENTITY column.
java.util.ConcurrentModificationException
A collection was modified while being iterated (even in a single thread).
HTTP 412 Precondition Failed
A conditional request header (If-Match, If-Unmodified-Since) didn’t match the current state of the resource.
HTTP 428 Precondition Required
The server requires a conditional request (If-Match / If-Unmodified-Since) to prevent lost updates, and you didn’t send one.
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