Look up an Oracle Database error by its ORA- or PLS- code or message: what it means, why it happens, read-only checks and safe fixes, based on Oracle's own error reference.
Common errors 13
ORA-00001
unique constraint violatedAn INSERT, UPDATE or MERGE would duplicate a primary key, unique constraint or unique index value.
ORA-02291
integrity constraint violated - parent key not foundA foreign key value has no matching parent row.
ORA-00942
table or view does not existThe table is missing, in another schema, not granted, or has a quoted name.
ORA-00904
invalid identifierA column or name that does not exist, is out of scope, or needs quotes.
ORA-01722
invalid numberA string could not be converted to a number.
ORA-12899
value too large for columnA string is longer than the column allows (in bytes or characters).
ORA-06502
PL/SQL: value or conversion errorA value did not fit a PL/SQL variable: string too long, too many digits, bad conversion or NULL into NOT NULL.
ORA-06512
at line (PL/SQL error stack)A stack line, not the real error: read the error above it and the unit and line it names.
ORA-01403
no data foundA SELECT INTO returned no rows (NO_DATA_FOUND).
ORA-00060
deadlock detected while waiting for resourceTransactions waited on each other in a cycle; Oracle rolled back one statement.
ORA-01017
invalid credential or not authorized; logon deniedWrong user name or password, password case, or the wrong PDB or service.
ORA-12154
cannot find alias (could not resolve the connect identifier)The client could not resolve the alias or connect identifier through tnsnames.ora, Easy Connect or LDAP.
ORA-12514
service is not registered with the listenerA listener answered but does not know the requested SERVICE_NAME: wrong name, PDB or instance not open, or not registered yet.
Constraints & Integrity 4
ORA-00001
unique constraint violatedAn INSERT, UPDATE or MERGE would duplicate a primary key, unique constraint or unique index value.
ORA-01400
cannot insert NULL intoAn INSERT would store NULL in a NOT NULL, primary key or identity column.
ORA-02291
integrity constraint violated - parent key not foundA foreign key value has no matching parent row.
ORA-02292
integrity constraint violated - child record foundDeleting or changing a parent key that child rows still reference.
SQL Syntax & Query Structure 7
ORA-00907
missing right parenthesisA bracket is missing, or the brackets contain a word Oracle does not accept.
ORA-00911
invalid characterA symbol in an unquoted name, a trailing semicolon from code, or pasted curly quotes.
ORA-00933
SQL command not properly endedExtra or unsupported text after a complete statement, such as LIMIT.
ORA-00936
missing expressionA required value or expression is missing, often a comma before FROM.
ORA-00937
not a single-group group functionA group function is mixed with a plain column and there is no GROUP BY.
ORA-00979
not a GROUP BY expressionA SELECT, HAVING or ORDER BY expression is not in the GROUP BY clause or an aggregate.
ORA-01427
single-row subquery returns more than one rowA subquery used as a single value returned several rows.
Objects, Names & Identifiers 4
ORA-00942
table or view does not existThe table is missing, in another schema, not granted, or has a quoted name.
ORA-00904
invalid identifierA column or name that does not exist, is out of scope, or needs quotes.
ORA-00918
column ambiguously definedAn unqualified column that exists in more than one joined table.
ORA-00955
name is already used by an existing objectCREATE uses a name another object in the schema namespace already has.
Data Types & Conversion 6
ORA-01722
invalid numberA string could not be converted to a number.
ORA-12899
value too large for columnA string is longer than the column allows (in bytes or characters).
ORA-00932
inconsistent datatypesAn expression has a data type the operation cannot use, such as a NUMBER compared with a DATE.
ORA-01843
not a valid monthThe month part of a date string is not a valid month for the format or date language.
ORA-01861
literal does not match format stringA date or timestamp string does not match the format model or NLS_DATE_FORMAT.
ORA-01438
value larger than specified precision allowed for this columnA number has more digits before the point than NUMBER(p,s) allows.
PL/SQL & Triggers 11
ORA-06502
PL/SQL: value or conversion errorA value did not fit a PL/SQL variable: string too long, too many digits, bad conversion or NULL into NOT NULL.
ORA-06512
at line (PL/SQL error stack)A stack line, not the real error: read the error above it and the unit and line it names.
ORA-01403
no data foundA SELECT INTO returned no rows (NO_DATA_FOUND).
ORA-01422
exact fetch returned more than the requested number of rowsA SELECT INTO or RETURNING INTO returned more than one row (TOO_MANY_ROWS).
ORA-01008
value for bind variable placeholder was not providedA statement ran without a value for one of its bind placeholders (USING clause, repeated placeholder, driver binds).
ORA-06550
line, column: (PL/SQL compilation error)A PL/SQL block failed to compile; the PLS- error on the next line says why.
ORA-04091
table is mutating, trigger/function may not see itA row trigger or a function called from DML read or changed the table being modified.
ORA-20000
user-defined error (RAISE_APPLICATION_ERROR, ORA-20000 to ORA-20999)An application error raised on purpose with RAISE_APPLICATION_ERROR; the message is the application's.
PLS-00201
identifier must be declaredA name could not be resolved: misspelt, out of scope, missing, or no direct privilege (roles do not count in stored code).
PLS-00103
Encountered the symbol ... when expecting one of the followingA PL/SQL syntax error: a missing semicolon, END or THEN, a reserved word as a name, or DDL in a block.
PLS-00306
wrong number or types of arguments in callA call matches no declaration of the subprogram: wrong argument count, wrong types or no matching overload.
Locking, Transactions & Sessions 3
ORA-00060
deadlock detected while waiting for resourceTransactions waited on each other in a cycle; Oracle rolled back one statement.
ORA-00054
resource busy (failed to acquire a lock held by another session)A lock needed by DDL, NOWAIT or a lock timeout is held by another session.
ORA-01555
snapshot too oldA long query needed undo that other transactions had already overwritten.
Logins, Accounts & Privileges 5
ORA-01017
invalid credential or not authorized; logon deniedWrong user name or password, password case, or the wrong PDB or service.
ORA-28000
The account is locked; login denied.The account was locked by failed logins, an administrator or in the root.
ORA-28001
The account has expired. The password must be changed.The password expired (life time and grace period passed, or expired by a DBA).
ORA-01031
insufficient privilegesA missing system or object privilege, a role ignored in a procedure, or SYSDBA.
ORA-65096
common user or role name must start with prefix C##CREATE USER or ROLE in CDB$ROOT without C##; connect to the PDB instead.
Space, Memory & Resource Limits 3
ORA-01652
unable to extend temp segmentA temporary segment (sort, hash, index build) could not grow in its tablespace.
ORA-01653
unable to extend tableA table could not get another extent because its tablespace is full and cannot grow.
ORA-01000
maximum open cursors exceededA session has more cursors open than OPEN_CURSORS allows, usually a cursor leak.
Connectivity & Listener 6
ORA-12154
cannot find alias (could not resolve the connect identifier)The client could not resolve the alias or connect identifier through tnsnames.ora, Easy Connect or LDAP.
ORA-12514
service is not registered with the listenerA listener answered but does not know the requested SERVICE_NAME: wrong name, PDB or instance not open, or not registered yet.
ORA-12541
no listener at the host and portNothing is listening at the host and port (or IPC key) in the connect string: listener stopped or wrong address.
ORA-12170
connect timeout occurredThe connection did not complete in time: firewall, unreachable address, slow network or too-short Oracle Net timeouts.
ORA-12560
database communication protocol error (TNS:protocol adapter error)A lower-level protocol adapter failed; on Windows usually OracleServiceSID not running or ORACLE_SID wrong for a local login.
ORA-03113
end-of-file on communication channelThe connection to the server process broke mid-session: instance outage, server process failure or network interruption.
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