# JSON format settings

JSON settings control field conversion, quoting, header matching and document layout. Use a SETTINGS clause on the statement; the next statement starts from defaults again.

A setting applies only to the JSON layouts that support it. Whole-object json_as_object and json_as_string input does not use the ordinary row JSON options. The individual format pages list their applicable subset.

The ordinary json_each_row codec always writes numeric values as JSON numbers; the json_quote options do not change it. Choose a supported compact/object layout when quoted numeric output is required.

Use a statement `SETTINGS` clause. Defaults in `system.settings` are read-only;
format settings cannot be persisted with `SET`. Put input settings before
`FORMAT`, because the bytes after the format name are input data.

## json_array_of_rows

Type: `Bool`

Default value: `0`

Wrap all output rows in one JSON array.

Applies to: `json_compact_each_row`, `json_compact_each_row_with_names_and_types`, `json_compact_strings_each_row`, `json_strings_each_row`.

## json_arrays_as_strings

Type: `Bool`

Default value: `1`

Accept JSON arrays in string input columns and retain their JSON text.

Applies to: `json_compact_each_row`, `json_compact_each_row_with_names_and_types`, `json_object_each_row`.

## json_bools_as_numbers

Type: `Bool`

Default value: `1`

Accept JSON Boolean input in numeric columns as zero or one.

Applies to: `json_compact_each_row`, `json_compact_each_row_with_names_and_types`, `json_object_each_row`.

## json_bools_as_strings

Type: `Bool`

Default value: `1`

Accept JSON Boolean input in string columns as true or false text.

Applies to: `json_compact_each_row`, `json_compact_each_row_with_names_and_types`, `json_object_each_row`.

## json_check_types

Type: `Bool`

Default value: `1`

Compare input metadata or header types with the bound target column types.

Applies to: `json`, `json_compact_each_row_with_names_and_types`.

## json_columns_sql_defaults

Type: `Bool`

Default value: `1`

Evaluate SQL DEFAULT expressions for omitted input columns; off supplies only their native type defaults.

Applies to: `json_columns`.

## json_compact_columns_sql_defaults

Type: `Bool`

Default value: `1`

Evaluate SQL DEFAULT expressions for omitted trailing input columns; off supplies only their native type defaults.

Applies to: `json_compact_columns`.

## json_compact_strings_each_row_sql_defaults

Type: `Bool`

Default value: `1`

Evaluate SQL DEFAULT expressions for missing or defaulted positional whole-text JSON fields; off supplies their native type defaults.

Applies to: `json_compact_strings_each_row`.

## json_compact_uneven_rows

Type: `Bool`

Default value: `0`

Give missing positional fields their SQL or native defaults and validate then skip extra fields.

Applies to: `json_compact_each_row`, `json_compact_each_row_with_names_and_types`, `json_compact_strings_each_row`.

## json_empty_as_default

Type: `Bool`

Default value: `0`

Give empty JSON string fields their SQL or native type default.

Applies to: `json_compact_each_row`, `json_compact_each_row_with_names_and_types`, `json_compact_strings_each_row`, `json_object_each_row`, `json_strings_each_row`.

## json_escape_slashes

Type: `Bool`

Default value: `1`

Escape unescaped forward slashes in JSON output strings.

Applies to: `json_compact_each_row`, `json_compact_each_row_with_names_and_types`, `json_compact_strings_each_row`, `json_object_each_row`, `json_strings_each_row`.

## json_match_names

Type: `Bool`

Default value: `1`

Match input header names to target columns ignoring ASCII case; when off, skip the names header and read in target order.

Applies to: `json_compact_each_row_with_names_and_types`.

## json_named_tuples_as_objects

Type: `Bool`

Default value: `1`

Read and write named Tuple values as objects; otherwise use positional arrays.

Applies to: `json_compact_each_row`, `json_compact_each_row_with_names_and_types`, `json_object_each_row`.

## json_numbers_as_strings

Type: `Bool`

Default value: `1`

Accept JSON numbers in string input columns and retain their exact spelling.

Applies to: `json_compact_each_row`, `json_compact_each_row_with_names_and_types`, `json_object_each_row`.

## json_object_each_row_name_column

Type: `String`

Default value: `''`

Use this string column for outer row keys and omit it from row objects; empty generates row_1, row_2, and so on.

Applies to: `json_object_each_row`.

## json_object_each_row_sql_defaults

Type: `Bool`

Default value: `1`

Evaluate SQL DEFAULT expressions for omitted or defaulted row fields; off supplies only their native type defaults.

Applies to: `json_object_each_row`.

## json_objects_as_strings

Type: `Bool`

Default value: `1`

Accept JSON objects in string input columns and retain their JSON text.

Applies to: `json_compact_each_row`, `json_compact_each_row_with_names_and_types`, `json_object_each_row`.

## json_quote_decimals

Type: `Bool`

Default value: `0`

Write fixed-point decimal output values as JSON strings.

Applies to: `json_compact_each_row`, `json_compact_each_row_with_names_and_types`, `json_object_each_row`.

## json_quote_large_floats

Type: `Bool`

Default value: `0`

Write finite Float64 output values as JSON strings.

Applies to: `json_compact_each_row`, `json_compact_each_row_with_names_and_types`, `json_object_each_row`.

## json_quote_large_integers

Type: `Bool`

Default value: `0`

Write integers of at least 64 bits as JSON strings; retained narrow types stay numeric.

Applies to: `json`, `json_compact_each_row`, `json_compact_each_row_with_names_and_types`, `json_object_each_row`.

## json_quote_special_floats

Type: `Bool`

Default value: `0`

Write non-finite floats as inf, -inf, nan, or -nan strings instead of JSON null.

Applies to: `json`, `json_compact_each_row`, `json_compact_each_row_with_names_and_types`, `json_object_each_row`.

## json_strict_escapes

Type: `Bool`

Default value: `1`

Reject invalid JSON escapes; otherwise preserve their literal backslash spelling.

Applies to: `json_compact_each_row`, `json_compact_each_row_with_names_and_types`, `json_compact_strings_each_row`, `json_object_each_row`, `json_strings_each_row`.

## json_strings_each_row_sql_defaults

Type: `Bool`

Default value: `1`

Evaluate SQL DEFAULT expressions for omitted or defaulted whole-text JSON fields; off supplies their native type defaults.

Applies to: `json_strings_each_row`.

## json_tuple_ignore_unknown_fields

Type: `Bool`

Default value: `0`

Validate then ignore object members outside a named Tuple declaration.

Applies to: `json_compact_each_row`, `json_compact_each_row_with_names_and_types`, `json_object_each_row`.

## json_tuple_missing_as_default

Type: `Bool`

Default value: `1`

Give missing named Tuple members their declared type defaults.

Applies to: `json_compact_each_row`, `json_compact_each_row_with_names_and_types`, `json_object_each_row`.

## json_validate_utf8

Type: `Bool`

Default value: `0`

Replace invalid UTF-8 sequences in whole-text JSON output with replacement characters; off preserves byte-string payloads.

Applies to: `json_compact_strings_each_row`, `json_strings_each_row`.