Oracle Error ORA-01400

Error code

ORA-01400

Product

Oracle Database

Versions

Oracle Database 19c, 21c, 23ai and 26ai (same wording)

Category

Constraints & Integrity

Last reviewed

24 October 2026

What it means

ORA-01400 means an INSERT (or the insert branch of a MERGE) would store NULL in a column that does not accept NULL, so Oracle rejected the statement. The message names the schema, table and column.

A column declared NOT NULL, and every primary key and identity column, must hold a value in every row. When an INSERT supplies NULL for such a column, either explicitly or by leaving the column out when it has no default, Oracle rolls back the statement and raises ORA-01400. Unlike many constraint errors, the message names the exact column as "SCHEMA"."TABLE"."COLUMN", so you know at once where to look.

A NULL is not the same as a missing column. A column default is used only when the INSERT leaves the column out; if the statement names the column and passes NULL (for example from an empty application field or a NULL in a source table), the default is skipped and the NOT NULL rule fires. Oracle's DEFAULT ... ON NULL clause exists for exactly that case. Setting an existing value to NULL with UPDATE raises a different error, ORA-01407. Oracle's current reference also notes that reservable columns (used for lock-free reservations) cannot accept NULL values.

Common causes

• The INSERT leaves out a NOT NULL column that has no default, so Oracle fills it with NULL.
• The application binds NULL for a required field, such as an empty form value or a missing JSON property.
• An INSERT ... SELECT or a load reads NULLs from the source for a column that is NOT NULL in the target.
• NULL is passed explicitly to a column with a plain DEFAULT, which only applies when the column is omitted.
• NULL is passed to a GENERATED BY DEFAULT identity column (without ON NULL), or the key column is left empty when no sequence or identity fills it.

Diagnose it

Read-only These queries only read the data dictionary (USER_, ALL_ and DBA_ views) and dynamic performance views (V$). They do not change data, privileges or settings, so they are safe to run first. DBA_ and V$ views need the matching privileges.

SELECT column_name, nullable, data_default, default_on_null, identity_column
FROM all_tab_columns
WHERE owner = 'SHOP'
  AND table_name = 'CUSTOMERS'
ORDER BY column_id;

SELECT *
FROM shop.customers_staging
WHERE email IS NULL;

SELECT trigger_name, trigger_type, triggering_event, status
FROM all_triggers
WHERE table_owner = 'SHOP'
  AND table_name = 'CUSTOMERS';

How to fix it

Each fix is labelled with what it changes. Try read-only checks and the least invasive fix first, and test changes outside production.

INSERT INTO shop.customers (email, name)
VALUES ('sara@example.com', 'Sara Ahmed');

INSERT INTO shop.customers (email, name)
SELECT s.email, NVL(s.name, 'Unknown')
FROM shop.customers_staging s
WHERE s.email IS NOT NULL;

ALTER TABLE shop.customers
  MODIFY status DEFAULT ON NULL 'ACTIVE';

ALTER TABLE shop.customers
  MODIFY id GENERATED BY DEFAULT ON NULL AS IDENTITY;

Examples

Leaving out a required column

Not reproduced here: no Oracle Database is installed for this site. The result shows the message format documented in Oracle's error reference, with the column given as schema, table and column; the schema name SHOP is illustrative. The wording is the same in 19c and current releases.

CREATE TABLE customers (
    id    NUMBER GENERATED BY DEFAULT AS IDENTITY PRIMARY KEY,
    email VARCHAR2(200) NOT NULL,
    name  VARCHAR2(100)
);

INSERT INTO customers (name) VALUES ('Sara');

ORA-01400: cannot insert NULL into ("SHOP"."CUSTOMERS"."EMAIL")

Passing NULL to a column that has a plain DEFAULT

Not reproduced here: no Oracle Database is installed for this site. The behaviour follows Oracle's SQL Language Reference (a plain DEFAULT applies when the column is omitted; DEFAULT ON NULL also covers an explicit NULL), and the message format comes from Oracle's error reference. The schema name is illustrative.

CREATE TABLE orders (
    id     NUMBER PRIMARY KEY,
    status VARCHAR2(20) DEFAULT 'NEW' NOT NULL
);

-- the default is used here, because status is left out
INSERT INTO orders (id) VALUES (1);

-- but not here: the statement assigns NULL explicitly
INSERT INTO orders (id, status) VALUES (2, NULL);

ORA-01400: cannot insert NULL into ("SHOP"."ORDERS"."STATUS")

How to prevent it

Mark every required field as NOT NULL and keep the rule in the table, then check the same fields in the application so users see a friendly message. Name all target columns in INSERT statements instead of relying on column order.

Before loading data, count the NULLs in each column that is required in the target and decide how to handle them. Where callers routinely pass NULL for "use the default", declare the column with DEFAULT ON NULL rather than repeating the default in every program.

Common questions

Learn more on CodeWithSQL

• SQL NULL values explained
• SQL constraints explained

Official documentation

• ORA-01400 (Oracle Database Error Messages)
• CREATE TABLE: DEFAULT ON NULL and identity columns (Oracle SQL Language Reference 26ai)
• ALL_TAB_COLUMNS (Oracle Database Reference 19c)

Last technically reviewed 24 October 2026; examples and diagnostics run on Oracle Database Error Messages reference (26ai, 21c and 19c); not run locally. Messages and explanations follow Oracle's Database Error Messages reference; no Oracle Database was available, so the examples were not run locally.