INSERT

You can use the INSERT statement to insert new rows into a table.

Table of contents

Synopsis

CrateDB defines the full INSERT syntax as:

INSERT INTO table_ident
  [ ( column_ident [, ...] ) ]
  { VALUES ( expression [, ...] ) [, ...] | ( query ) | query }
  [ ON CONFLICT (column_ident [, ...]) DO UPDATE SET { column_ident = expression [, ...] } |
    ON CONFLICT [ ( column_ident [, ...] ) ] DO NOTHING ]
  [ RETURNING { * | output_expression [ [ AS ] output_name ] | relation.* } [, ...] ]

Parameters

table_ident

The identifier (optionally schema-qualified) of an existing table.

column_ident

The name of a column or field in the table_ident table.

expression

An expression or value to assign to the corresponding column.

query

A query (i.e., SELECT) that supplies rows for the statement to insert.

output_expression

An expression to be computed and returned by the INSERT statement after each row is updated. This expression can use any of the table column names, the * character to return all table columns, as well as any system columns.

output_name

A name to use for the result of the output expression.

Description

The INSERT statement creates one or more rows specified by value expressions.

You can list target column names in any order. If you omit the target column names, they default to all columns of the table or up to n columns if there are fewer values in the VALUES clause or query.

CrateDB will order implicitly inferred column names by their ordinal value. The ordinal value depends on the ordering of the columns within the CREATE TABLE statement.

The values supplied by the VALUES clause or query are associated with the explicit or implicit column list left-to-right.

CrateDB will not fill any column not present in the explicit or implicit column list.

If the expression for any column is not of the correct data type, CrateDB will attempt automatic type conversion.

The optional RETURNING clause causes the INSERT statement to compute and return values from each row inserted (or updated, in the case of ON CONFLICT DO UPDATE). You can take advantage of this behavior to obtain values that CrateDB supplied from defaults, such as as _id.

Caution

Dynamic SELECT statements may produce inconsistent values for insertion when used with the query parameter.

For example, this use of unnest produces a single column (foo) with incompatible data types (numeric and character, respectively):

SELECT unnest([{foo=1}, {foo='a string'}])

The same problem could happen like this:

INSERT INTO table_a (obj_col) VALUES ({foo=1}), ({foo='a string'})
INSERT INTO table_a (int_col) (SELECT obj_col['foo'] FROM table_a)

In this example, problems will arise if valid_col is a valid column name, but invalid_col is not:

SELECT unnest([{valid_col='foo', invalid_col='bar'}])

Any inserts that were successful before CrateDB encountered an error will remain, but CrateDB will reject the rest, potentially leading to inconsistent data.

Users need to take special care when inserting data from queries that might produce dynamic values like the ones above.

ON CONFLICT DO UPDATE SET

If your table has a primary key, you can use the ON CONFLICT DO UPDATE SET clause to modify the existing record (instead of inserting a new one) if CrateDB encounters a primary key conflict during the INSERT operation.

Syntax:

ON CONFLICT (conflict_target) DO UPDATE SET { assignments }

Where conflict_target can be one or more column identifiers:

column_ident [, ... ]

And assignments can be one or more column assignments:

assignments = expression [, ... ]

Note

CrateDB does not support unique constraints, foreign key constraints, or exclusion constraints (see SQL compatibility: Unsupported features and functions). Therefore, the only constraint capable of producing a conflict that CrateDB supports is a primary key constraint.

When using the ON CONFLICT DO UPDATE SET clause with a primary key constraint, the conflict_target must always match the primary key definition.

For example, if my_table had a primary key col_a, the correct syntax would be:

ON CONFLICT (col_a) DO UPDATE SET { assignments }

However, if my_table had a primary key on both col_a and col_b, the correct syntax would be:

ON CONFLICT (col_a, col_b) DO UPDATE SET { assignments }

For example:

cr> INSERT INTO uservisits (id, name, visits, last_visit) VALUES
... (
...     0,
...     'Ford',
...     1,
...     '2015-09-12'
... ) ON CONFLICT (id) DO UPDATE SET
...     visits = visits + 1;
INSERT OK, 1 row affected (... sec)

This statement instructs CrateDB to do the following:

  • Attempt to insert a new uservisits record for user ID 0.

  • If the insert would cause a primary key conflict on id (i.e., the user already has a record in the uservists table), update the existing record by incrementing the visits count.

You can also use a virtual table named excluded to reference values from the failed (i.e., excluded) INSERT record. For example:

cr> INSERT INTO uservisits (id, name, visits, last_visit) VALUES
... (
...     0,
...     'Ford',
...     1,
...     '2015-09-12'
... ) ON CONFLICT (id) DO UPDATE SET
...     visits = visits + 1,
...     last_visit = excluded.last_visit;
INSERT OK, 1 row affected (... sec)

The addition of last_visit = excluded.last_visit instructs CrateDB to overwrite the existing value of last_visits with the attempted insert value.

ON CONFLICT DO NOTHING

If you use the ON CONFLICT DO NOTHING clause, CrateDB will silently ignore rows that would cause a duplicate key conflict (i.e., CrateDB will not insert them and will not produce an error). For example:

INSERT INTO my_table (col_a, col_b) VALUES (1, 42)
ON CONFLICT DO NOTHING

In the statement above, if col_a had a primary key constraint and the value 1 already existed for col_a, CrateDB would not perform an insert.

Note

You may specify an explicit primary key as the conflict_target (i.e., ON CONFLICT (conflict_target) DO NOTHING), as with ON CONFLICT DO UPDATE SET. However, doing so is optional.

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