ALTER FILE FORMAT

Modifies the properties for an existing file format object. Currently the only actions that are supported are renaming the file format, changing the file format options (based on the type), and adding/changing a comment. To make any other changes, you must drop the file format and then recreate it.

See also:

CREATE FILE FORMAT , DROP FILE FORMAT , SHOW FILE FORMATS , DESCRIBE FILE FORMAT

Syntax

ALTER FILE FORMAT [ IF EXISTS ] <name> RENAME TO <new_name>

ALTER FILE FORMAT [ IF EXISTS ] <name> SET { [ formatTypeOptions ] [ COMMENT = '<string_literal>' ] }
Copy

Where:

formatTypeOptions ::=
-- If TYPE = CSV
     COMPRESSION = AUTO | GZIP | BZ2 | BROTLI | ZSTD | DEFLATE | RAW_DEFLATE | NONE
     RECORD_DELIMITER = '<character>' | NONE
     FIELD_DELIMITER = '<character>' | NONE
     FILE_EXTENSION = '<string>'
     PARSE_HEADER = TRUE | FALSE
     SKIP_HEADER = <integer>
     SKIP_BLANK_LINES = TRUE | FALSE
     DATE_FORMAT = '<string>' | AUTO
     TIME_FORMAT = '<string>' | AUTO
     TIMESTAMP_FORMAT = '<string>' | AUTO
     BINARY_FORMAT = HEX | BASE64 | UTF8
     ESCAPE = '<character>' | NONE
     ESCAPE_UNENCLOSED_FIELD = '<character>' | NONE
     TRIM_SPACE = TRUE | FALSE
     FIELD_OPTIONALLY_ENCLOSED_BY = '<character>' | NONE
     NULL_IF = ( '<string>' [ , '<string>' ... ] )
     ERROR_ON_COLUMN_COUNT_MISMATCH = TRUE | FALSE
     REPLACE_INVALID_CHARACTERS = TRUE | FALSE
     EMPTY_FIELD_AS_NULL = TRUE | FALSE
     SKIP_BYTE_ORDER_MARK = TRUE | FALSE
     ENCODING = '<string>' | UTF8
-- If TYPE = JSON
     COMPRESSION = AUTO | GZIP | BZ2 | BROTLI | ZSTD | DEFLATE | RAW_DEFLATE | NONE
     DATE_FORMAT = '<string>' | AUTO
     TIME_FORMAT = '<string>' | AUTO
     TIMESTAMP_FORMAT = '<string>' | AUTO
     BINARY_FORMAT = HEX | BASE64 | UTF8
     TRIM_SPACE = TRUE | FALSE
     NULL_IF = ( '<string>' [ , '<string>' ... ] )
     FILE_EXTENSION = '<string>'
     ENABLE_OCTAL = TRUE | FALSE
     ALLOW_DUPLICATE = TRUE | FALSE
     STRIP_OUTER_ARRAY = TRUE | FALSE
     STRIP_NULL_VALUES = TRUE | FALSE
     REPLACE_INVALID_CHARACTERS = TRUE | FALSE
     IGNORE_UTF8_ERRORS = TRUE | FALSE
     SKIP_BYTE_ORDER_MARK = TRUE | FALSE
-- If TYPE = AVRO
     COMPRESSION = AUTO | GZIP | BROTLI | ZSTD | DEFLATE | RAW_DEFLATE | NONE
     TRIM_SPACE = TRUE | FALSE
     REPLACE_INVALID_CHARACTERS = TRUE | FALSE
     NULL_IF = ( '<string>' [ , '<string>' ... ] )
-- If TYPE = ORC
     TRIM_SPACE = TRUE | FALSE
     REPLACE_INVALID_CHARACTERS = TRUE | FALSE
     NULL_IF = ( '<string>' [ , '<string>' ... ] )
-- If TYPE = PARQUET
     COMPRESSION = AUTO | LZO | SNAPPY | NONE
     SNAPPY_COMPRESSION = TRUE | FALSE
     BINARY_AS_TEXT = TRUE | FALSE
     USE_LOGICAL_TYPE = TRUE | FALSE
     TRIM_SPACE = TRUE | FALSE
     REPLACE_INVALID_CHARACTERS = TRUE | FALSE
     NULL_IF = ( '<string>' [ , '<string>' ... ] )
-- If TYPE = XML
     COMPRESSION = AUTO | GZIP | BZ2 | BROTLI | ZSTD | DEFLATE | RAW_DEFLATE | NONE
     IGNORE_UTF8_ERRORS = TRUE | FALSE
     PRESERVE_SPACE = TRUE | FALSE
     STRIP_OUTER_ELEMENT = TRUE | FALSE
     DISABLE_SNOWFLAKE_DATA = TRUE | FALSE
     DISABLE_AUTO_CONVERT = TRUE | FALSE
     REPLACE_INVALID_CHARACTERS = TRUE | FALSE
     SKIP_BYTE_ORDER_MARK = TRUE | FALSE
Copy

Parameters

name

Specifies the identifier for the file format to alter. If the identifier contains spaces or special characters, the entire string must be enclosed in double quotes. Identifiers enclosed in double quotes are also case-sensitive.

RENAME TO new_name

Specifies the new identifier for the file format; must be unique for the schema.

For more details, see Identifier requirements.

You can move the object to a different database and/or schema while optionally renaming the object. To do so, specify a qualified new_name value that includes the new database and/or schema name in the form db_name.schema_name.object_name or schema_name.object_name, respectively.

Note

  • The destination database and/or schema must already exist. In addition, an object with the same name cannot already exist in the new location; otherwise, the statement returns an error.

  • Moving an object to a managed access schema is prohibited unless the object owner (i.e. the role that has the OWNERSHIP privilege on the object) also owns the target schema.

When an object is renamed, other objects that reference it must be updated with the new name.

SET ...

Specifies the options/properties to set for the file format:

FILE_FORMAT = ( ... )

Modifies the format-specific options for the file format. For more details, see Format Type Options (in this topic).

COMMENT = 'string_literal'

Adds a comment or overwrites the existing comment for the file format.

Format Type Options (formatTypeOptions)

Depending on the file format type specified (TYPE = ...), you can include one or more of the following format-specific options (separated by blank spaces, commas, or new lines):

TYPE = CSV

COMPRESSION = AUTO | GZIP | BZ2 | BROTLI | ZSTD | DEFLATE | RAW_DEFLATE | NONE
Use:

Data loading, data unloading, and external tables

Definition:
  • When loading data, specifies the current compression algorithm for the data file. Snowflake uses this option to detect how an already-compressed data file was compressed so that the compressed data in the file can be extracted for loading.

  • When unloading data, compresses the data file using the specified compression algorithm.

Values:

Supported Values

Notes

AUTO

When loading data, compression algorithm detected automatically, except for Brotli-compressed files, which cannot currently be detected automatically. When unloading data, files are automatically compressed using the default, which is gzip.

GZIP

BZ2

BROTLI

Must be specified when loading/unloading Brotli-compressed files.

ZSTD

Zstandard v0.8 (and higher) is supported.

DEFLATE

Deflate-compressed files (with zlib header, RFC1950).

RAW_DEFLATE

Raw Deflate-compressed files (without header, RFC1951).

NONE

When loading data, indicates that the files have not been compressed. When unloading data, specifies that the unloaded files are not compressed.

Default:

AUTO

RECORD_DELIMITER = 'character' | NONE
Use:

Data loading, data unloading, and external tables

Definition:

One or more singlebyte or multibyte characters that separate records in an input file (data loading) or unloaded file (data unloading). Accepts common escape sequences or the following singlebyte or multibyte characters:

Singlebyte characters:

Octal values (prefixed by \\) or hex values (prefixed by 0x or \x). For example, for records delimited by the circumflex accent (^) character, specify the octal (\\136) or hex (0x5e) value.

Multibyte characters:

Hex values (prefixed by \x). For example, for records delimited by the cent (¢) character, specify the hex (\xC2\xA2) value.

The delimiter for RECORD_DELIMITER or FIELD_DELIMITER cannot be a substring of the delimiter for the other file format option (e.g. FIELD_DELIMITER = 'aa' RECORD_DELIMITER = 'aabb').

The specified delimiter must be a valid UTF-8 character and not a random sequence of bytes. Also note that the delimiter is limited to a maximum of 20 characters.

Also accepts a value of NONE.

Default:
Data loading:

New line character. Note that “new line” is logical such that \r\n will be understood as a new line for files on a Windows platform.

Data unloading:

New line character (\n).

FIELD_DELIMITER = 'character' | NONE
Use:

Data loading, data unloading, and external tables

Definition:

One or more singlebyte or multibyte characters that separate fields in an input file (data loading) or unloaded file (data unloading). Accepts common escape sequences or the following singlebyte or multibyte characters:

Singlebyte characters:

Octal values (prefixed by \\) or hex values (prefixed by 0x or \x). For example, for records delimited by the circumflex accent (^) character, specify the octal (\\136) or hex (0x5e) value.

Multibyte characters:

Hex values (prefixed by \x). For example, for records delimited by the cent (¢) character, specify the hex (\xC2\xA2) value.

The delimiter for RECORD_DELIMITER or FIELD_DELIMITER cannot be a substring of the delimiter for the other file format option (e.g. FIELD_DELIMITER = 'aa' RECORD_DELIMITER = 'aabb').

Note

For non-ASCII characters, you must use the hex byte sequence value to get a deterministic behavior.

The specified delimiter must be a valid UTF-8 character and not a random sequence of bytes. Also note that the delimiter is limited to a maximum of 20 characters.

Also accepts a value of NONE.

Default:

comma (,)

FILE_EXTENSION = 'string' | NONE
Use:

Data unloading only

Definition:

Specifies the extension for files unloaded to a stage. Accepts any extension. The user is responsible for specifying a file extension that can be read by any desired software or services.

Default:

null, meaning the file extension is determined by the format type: .csv[compression], where compression is the extension added by the compression method, if COMPRESSION is set.

Note

If the SINGLE copy option is TRUE, then the COPY command unloads a file without a file extension by default. To specify a file extension, provide a file name and extension in the internal_location or external_location path (e.g. copy into @stage/data.csv).

PARSE_HEADER = TRUE | FALSE
Use:

Data loading only

Definition:

Boolean that specifies whether to use the first row headers in the data files to determine column names.

This file format option is applied to the following actions only:

  • Automatically detecting column definitions by using the INFER_SCHEMA function.

  • Loading CSV data into separate columns by using the INFER_SCHEMA function and MATCH_BY_COLUMN_NAME copy option.

If the option is set to TRUE, the first row headers will be used to determine column names. The default value FALSE will return column names as c*, where * is the position of the column.

Note that the SKIP_HEADER option is not supported with PARSE_HEADER = TRUE.

Default: FALSE

SKIP_HEADER = integer
Use:

Data loading and external tables

Definition:

Number of lines at the start of the file to skip.

Note that SKIP_HEADER does not use the RECORD_DELIMITER or FIELD_DELIMITER values to determine what a header line is; rather, it simply skips the specified number of CRLF (Carriage Return, Line Feed)-delimited lines in the file. RECORD_DELIMITER and FIELD_DELIMITER are then used to determine the rows of data to load.

Default:

0

SKIP_BLANK_LINES = TRUE | FALSE
Use:

Data loading and external tables

Definition:

Boolean that specifies to skip any blank lines encountered in the data files; otherwise, blank lines produce an end-of-record error (default behavior).

Default: FALSE

DATE_FORMAT = 'string' | AUTO
Use:

Data loading and unloading

Definition:

Defines the format of date values in the data files (data loading) or table (data unloading). If a value is not specified or is AUTO, the value for the DATE_INPUT_FORMAT (data loading) or DATE_OUTPUT_FORMAT (data unloading) parameter is used.

Default:

AUTO

TIME_FORMAT = 'string' | AUTO
Use:

Data loading and unloading

Definition:

Defines the format of time values in the data files (data loading) or table (data unloading). If a value is not specified or is AUTO, the value for the TIME_INPUT_FORMAT (data loading) or TIME_OUTPUT_FORMAT (data unloading) parameter is used.

Default:

AUTO

TIMESTAMP_FORMAT = string' | AUTO
Use:

Data loading and unloading

Definition:

Defines the format of timestamp values in the data files (data loading) or table (data unloading). If a value is not specified or is AUTO, the value for the TIMESTAMP_INPUT_FORMAT (data loading) or TIMESTAMP_OUTPUT_FORMAT (data unloading) parameter is used.

Default:

AUTO

BINARY_FORMAT = HEX | BASE64 | UTF8
Use:

Data loading and unloading

Definition:

Defines the encoding format for binary input or output. The option can be used when loading data into or unloading data from binary columns in a table.

Default:

HEX

ESCAPE = 'character' | NONE
Use:

Data loading and unloading

Definition:

A singlebyte character string used as the escape character for enclosed or unenclosed field values. An escape character invokes an alternative interpretation on subsequent characters in a character sequence. You can use the ESCAPE character to interpret instances of the FIELD_OPTIONALLY_ENCLOSED_BY character in the data as literals.

Accepts common escape sequences, octal values, or hex values.

Loading data:

Specifies the escape character for enclosed fields only. Specify the character used to enclose fields by setting FIELD_OPTIONALLY_ENCLOSED_BY.

Note

This file format option supports singlebyte characters only. Note that UTF-8 character encoding represents high-order ASCII characters as multibyte characters. If your data file is encoded with the UTF-8 character set, you cannot specify a high-order ASCII character as the option value.

In addition, if you specify a high-order ASCII character, we recommend that you set the ENCODING = 'string' file format option as the character encoding for your data files to ensure the character is interpreted correctly.

Unloading data:

If this option is set, it overrides the escape character set for ESCAPE_UNENCLOSED_FIELD.

Default:

NONE

ESCAPE_UNENCLOSED_FIELD = 'character' | NONE
Use:

Data loading, data unloading, and external tables

Definition:

A singlebyte character string used as the escape character for unenclosed field values only. An escape character invokes an alternative interpretation on subsequent characters in a character sequence. You can use the ESCAPE character to interpret instances of the FIELD_DELIMITER or RECORD_DELIMITER characters in the data as literals. The escape character can also be used to escape instances of itself in the data.

Accepts common escape sequences, octal values, or hex values.

Loading data:

Specifies the escape character for unenclosed fields only.

Note

  • The default value is \\. If a row in a data file ends in the backslash (\) character, this character escapes the newline or carriage return character specified for the RECORD_DELIMITER file format option. As a result, the load operation treats this row and the next row as a single row of data. To avoid this issue, set the value to NONE.

  • This file format option supports singlebyte characters only. Note that UTF-8 character encoding represents high-order ASCII characters as multibyte characters. If your data file is encoded with the UTF-8 character set, you cannot specify a high-order ASCII character as the option value.

    In addition, if you specify a high-order ASCII character, we recommend that you set the ENCODING = 'string' file format option as the character encoding for your data files to ensure the character is interpreted correctly.

Unloading data:

If ESCAPE is set, the escape character set for that file format option overrides this option.

Default:

backslash (\\)

TRIM_SPACE = TRUE | FALSE
Use:

Data loading and external tables

Definition:

Boolean that specifies whether to remove white space from fields.

For example, if your external database software encloses fields in quotes, but inserts a leading space, Snowflake reads the leading space rather than the opening quotation character as the beginning of the field (i.e. the quotation marks are interpreted as part of the string of field data). Set this option to TRUE to remove undesirable spaces during the data load.

As another example, if leading or trailing spaces surround quotes that enclose strings, you can remove the surrounding spaces using this option and the quote character using the FIELD_OPTIONALLY_ENCLOSED_BY option. Note that any spaces within the quotes are preserved. For example, assuming FIELD_DELIMITER = '|' and FIELD_OPTIONALLY_ENCLOSED_BY = '"':

|"Hello world"|    /* loads as */  >Hello world<
|" Hello world "|  /* loads as */  > Hello world <
| "Hello world" |  /* loads as */  >Hello world<
Copy

(the brackets in this example are not loaded; they are used to demarcate the beginning and end of the loaded strings)

Default:

FALSE

FIELD_OPTIONALLY_ENCLOSED_BY = 'character' | NONE
Use:

Data loading, data unloading, and external tables

Definition:

Character used to enclose strings. Value can be NONE, single quote character ('), or double quote character ("). To use the single quote character, use the octal or hex representation (0x27) or the double single-quoted escape ('').

Data unloading only:

When a field in the source table contains this character, Snowflake escapes it using the same character for unloading. For example, if the value is the double quote character and a field contains the string A "B" C, Snowflake escapes the double quotes for unloading as follows:

A ""B"" C

Default:

NONE

NULL_IF = ( 'string1' [ , 'string2' , ... ] )
Use:

Data loading, data unloading, and external tables

Definition:

String used to convert to and from SQL NULL:

  • When loading data, Snowflake replaces these values in the data load source with SQL NULL. To specify more than one string, enclose the list of strings in parentheses and use commas to separate each value.

    Note that Snowflake converts all instances of the value to NULL, regardless of the data type. For example, if 2 is specified as a value, all instances of 2 as either a string or number are converted.

    For example:

    NULL_IF = ('\N', 'NULL', 'NUL', '')

    Note that this option can include empty strings.

  • When unloading data, Snowflake converts SQL NULL values to the first value in the list.

Default:

\\N (i.e. NULL, which assumes the ESCAPE_UNENCLOSED_FIELD value is \\)

ERROR_ON_COLUMN_COUNT_MISMATCH = TRUE | FALSE
Use:

Data loading only

Definition:

Boolean that specifies whether to generate a parsing error if the number of delimited columns (i.e. fields) in an input file does not match the number of columns in the corresponding table.

If set to FALSE, an error is not generated and the load continues. If the file is successfully loaded:

  • If the input file contains records with more fields than columns in the table, the matching fields are loaded in order of occurrence in the file and the remaining fields are not loaded.

  • If the input file contains records with fewer fields than columns in the table, the non-matching columns in the table are loaded with NULL values.

This option assumes all the records within the input file are the same length (i.e. a file containing records of varying length return an error regardless of the value specified for this parameter).

Default:

TRUE

Note

When transforming data during loading (i.e. using a query as the source for the COPY command), this option is ignored. There is no requirement for your data files to have the same number and ordering of columns as your target table.

REPLACE_INVALID_CHARACTERS = TRUE | FALSE
Use:

Data loading only

Definition:

Boolean that specifies whether to replace invalid UTF-8 characters with the Unicode replacement character ().

If set to TRUE, Snowflake replaces invalid UTF-8 characters with the Unicode replacement character.

If set to FALSE, the load operation produces an error when invalid UTF-8 character encoding is detected.

Default:

FALSE

EMPTY_FIELD_AS_NULL = TRUE | FALSE
Use:

Data loading, data unloading, and external tables

Definition:
  • When loading data, specifies whether to insert SQL NULL for empty fields in an input file, which are represented by two successive delimiters (e.g. ,,).

    If set to FALSE, Snowflake attempts to cast an empty field to the corresponding column type. An empty string is inserted into columns of type STRING. For other column types, the COPY command produces an error.

  • When unloading data, this option is used in combination with FIELD_OPTIONALLY_ENCLOSED_BY. When FIELD_OPTIONALLY_ENCLOSED_BY = NONE, setting EMPTY_FIELD_AS_NULL = FALSE specifies to unload empty strings in tables to empty string values without quotes enclosing the field values.

    If set to TRUE, FIELD_OPTIONALLY_ENCLOSED_BY must specify a character to enclose strings.

Default:

TRUE

SKIP_BYTE_ORDER_MARK = TRUE | FALSE
Use:

Data loading only

Definition:

Boolean that specifies whether to skip the BOM (byte order mark), if present in a data file. A BOM is a character code at the beginning of a data file that defines the byte order and encoding form.

If set to FALSE, Snowflake recognizes any BOM in data files, which could result in the BOM either causing an error or being merged into the first column in the table.

Default:

TRUE

ENCODING = 'string'
Use:

Data loading and external tables

Definition:

String (constant) that specifies the character set of the source data when loading data into a table.

Character Set

ENCODING Value

Supported Languages

Notes

Big5

BIG5

Traditional Chinese

EUC-JP

EUCJP

Japanese

EUC-KR

EUCKR

Korean

GB18030

GB18030

Chinese

IBM420

IBM420

Arabic

IBM424

IBM424

Hebrew

IBM949

IBM949

Korean

ISO-2022-CN

ISO2022CN

Simplified Chinese

ISO-2022-JP

ISO2022JP

Japanese

ISO-2022-KR

ISO2022KR

Korean

ISO-8859-1

ISO88591

Danish, Dutch, English, French, German, Italian, Norwegian, Portuguese, Swedish

ISO-8859-2

ISO88592

Czech, Hungarian, Polish, Romanian

ISO-8859-5

ISO88595

Russian

ISO-8859-6

ISO88596

Arabic

ISO-8859-7

ISO88597

Greek

ISO-8859-8

ISO88598

Hebrew

ISO-8859-9

ISO88599

Turkish

ISO-8859-15

ISO885915

Danish, Dutch, English, French, German, Italian, Norwegian, Portuguese, Swedish

Identical to ISO-8859-1 except for 8 characters, including the Euro currency symbol.

KOI8-R

KOI8R

Russian

Shift_JIS

SHIFTJIS

Japanese

UTF-8

UTF8

All languages

For loading data from delimited files (CSV, TSV, etc.), UTF-8 is the default. . . For loading data from all other supported file formats (JSON, Avro, etc.), as well as unloading data, UTF-8 is the only supported character set.

UTF-16

UTF16

All languages

UTF-16BE

UTF16BE

All languages

UTF-16LE

UTF16LE

All languages

UTF-32

UTF32

All languages

UTF-32BE

UTF32BE

All languages

UTF-32LE

UTF32LE

All languages

windows-949

WINDOWS949

Korean

windows-1250

WINDOWS1250

Czech, Hungarian, Polish, Romanian

windows-1251

WINDOWS1251

Russian

windows-1252

WINDOWS1252

Danish, Dutch, English, French, German, Italian, Norwegian, Portuguese, Swedish

windows-1253

WINDOWS1253

Greek

windows-1254

WINDOWS1254

Turkish

windows-1255

WINDOWS1255

Hebrew

windows-1256

WINDOWS1256

Arabic

Default:

UTF8

Note

Snowflake stores all data internally in the UTF-8 character set. The data is converted into UTF-8 before it is loaded into Snowflake.

TYPE = JSON

COMPRESSION = AUTO | GZIP | BZ2 | BROTLI | ZSTD | DEFLATE | RAW_DEFLATE | NONE
Use:

Data loading and external tables

Definition:
  • When loading data, specifies the current compression algorithm for the data file. Snowflake uses this option to detect how an already-compressed data file was compressed so that the compressed data in the file can be extracted for loading.

  • When unloading data, compresses the data file using the specified compression algorithm.

Values:

Supported Values

Notes

AUTO

When loading data, compression algorithm detected automatically, except for Brotli-compressed files, which cannot currently be detected automatically. When unloading data, files are automatically compressed using the default, which is gzip.

GZIP

BZ2

BROTLI

Must be specified if loading/unloading Brotli-compressed files.

ZSTD

Zstandard v0.8 (and higher) is supported.

DEFLATE

Deflate-compressed files (with zlib header, RFC1950).

RAW_DEFLATE

Raw Deflate-compressed files (without header, RFC1951).

NONE

When loading data, indicates that the files have not been compressed. When unloading data, specifies that the unloaded files are not compressed.

Default:

AUTO

DATE_FORMAT = 'string' | AUTO
Use:

Data loading only

Definition:

Defines the format of date string values in the data files. If a value is not specified or is AUTO, the value for the DATE_INPUT_FORMAT parameter is used.

This file format option is applied to the following actions only:

  • Loading JSON data into separate columns using the MATCH_BY_COLUMN_NAME copy option.

  • Loading JSON data into separate columns by specifying a query in the COPY statement (i.e. COPY transformation).

Default:

AUTO

TIME_FORMAT = 'string' | AUTO
Use:

Data loading only

Definition:

Defines the format of time string values in the data files. If a value is not specified or is AUTO, the value for the TIME_INPUT_FORMAT parameter is used.

This file format option is applied to the following actions only:

  • Loading JSON data into separate columns using the MATCH_BY_COLUMN_NAME copy option.

  • Loading JSON data into separate columns by specifying a query in the COPY statement (i.e. COPY transformation).

Default:

AUTO

TIMESTAMP_FORMAT = string' | AUTO
Use:

Data loading only

Definition:

Defines the format of timestamp string values in the data files. If a value is not specified or is AUTO, the value for the TIMESTAMP_INPUT_FORMAT parameter is used.

This file format option is applied to the following actions only:

  • Loading JSON data into separate columns using the MATCH_BY_COLUMN_NAME copy option.

  • Loading JSON data into separate columns by specifying a query in the COPY statement (i.e. COPY transformation).

Default:

AUTO

BINARY_FORMAT = HEX | BASE64 | UTF8
Use:

Data loading only

Definition:

Defines the encoding format for binary string values in the data files. The option can be used when loading data into binary columns in a table.

This file format option is applied to the following actions only:

  • Loading JSON data into separate columns using the MATCH_BY_COLUMN_NAME copy option.

  • Loading JSON data into separate columns by specifying a query in the COPY statement (i.e. COPY transformation).

Default:

HEX

TRIM_SPACE = TRUE | FALSE
Use:

Data loading only

Definition:

Boolean that specifies whether to remove leading and trailing white space from strings.

For example, if your external database software encloses fields in quotes, but inserts a leading space, Snowflake reads the leading space rather than the opening quotation character as the beginning of the field (i.e. the quotation marks are interpreted as part of the string of field data). Set this option to TRUE to remove undesirable spaces during the data load.

This file format option is applied to the following actions only when loading JSON data into separate columns using the MATCH_BY_COLUMN_NAME copy option.

Default:

FALSE

NULL_IF = ( 'string1' [ , 'string2' , ... ] )
Use:

Data loading only

Definition:

String used to convert to and from SQL NULL. Snowflake replaces these strings in the data load source with SQL NULL. To specify more than one string, enclose the list of strings in parentheses and use commas to separate each value.

This file format option is applied to the following actions only when loading JSON data into separate columns using the MATCH_BY_COLUMN_NAME copy option.

Note that Snowflake converts all instances of the value to NULL, regardless of the data type. For example, if 2 is specified as a value, all instances of 2 as either a string or number are converted.

For example:

NULL_IF = ('\N', 'NULL', 'NUL', '')

Note that this option can include empty strings.

Default:

\\N (i.e. NULL, which assumes the ESCAPE_UNENCLOSED_FIELD value is \\)

FILE_EXTENSION = 'string' | NONE
Use:

Data unloading only

Definition:

Specifies the extension for files unloaded to a stage. Accepts any extension. The user is responsible for specifying a file extension that can be read by any desired software or services.

Default:

null, meaning the file extension is determined by the format type: .json[compression], where compression is the extension added by the compression method, if COMPRESSION is set.

ENABLE_OCTAL = TRUE | FALSE
Use:

Data loading only

Definition:

Boolean that enables parsing of octal numbers.

Default:

FALSE

ALLOW_DUPLICATE = TRUE | FALSE
Use:

Data loading and external tables

Definition:

Boolean that specifies to allow duplicate object field names (only the last one will be preserved).

Default:

FALSE

STRIP_OUTER_ARRAY = TRUE | FALSE
Use:

Data loading and external tables

Definition:

Boolean that instructs the JSON parser to remove outer brackets (i.e. [ ]).

Default:

FALSE

STRIP_NULL_VALUES = TRUE | FALSE
Use:

Data loading and external tables

Definition:

Boolean that instructs the JSON parser to remove object fields or array elements containing null values. For example, when set to TRUE:

Before

After

[null]

[]

[null,null,3]

[,,3]

{"a":null,"b":null,"c":123}

{"c":123}

{"a":[1,null,2],"b":{"x":null,"y":88}}

{"a":[1,,2],"b":{"y":88}}

Default:

FALSE

REPLACE_INVALID_CHARACTERS = TRUE | FALSE
Use:

Data loading and external table

Definition:

Boolean that specifies whether to replace invalid UTF-8 characters with the Unicode replacement character (). This option performs a one-to-one character replacement.

Values:

If set to TRUE, Snowflake replaces invalid UTF-8 characters with the Unicode replacement character.

If set to FALSE, the load operation produces an error when invalid UTF-8 character encoding is detected.

Default:

FALSE

IGNORE_UTF8_ERRORS = TRUE | FALSE
Use:

Data loading and external table

Definition:

Boolean that specifies whether UTF-8 encoding errors produce error conditions. It is an alternative syntax for REPLACE_INVALID_CHARACTERS.

Values:

If set to TRUE, any invalid UTF-8 sequences are silently replaced with the Unicode character U+FFFD (i.e. “replacement character”).

If set to FALSE, the load operation produces an error when invalid UTF-8 character encoding is detected.

Default:

FALSE

SKIP_BYTE_ORDER_MARK = TRUE | FALSE
Use:

Data loading only

Definition:

Boolean that specifies whether to skip the BOM (byte order mark), if present in a data file. A BOM is a character code at the beginning of a data file that defines the byte order and encoding form.

If set to FALSE, Snowflake recognizes any BOM in data files, which could result in the BOM either causing an error or being merged into the first column in the table.

Default:

TRUE

TYPE = AVRO

COMPRESSION = AUTO | GZIP | BROTLI | ZSTD | DEFLATE | RAW_DEFLATE | NONE
Use:

Data loading only

Definition:
  • When loading data, specifies the current compression algorithm for the data file. Snowflake uses this option to detect how an already-compressed data file was compressed so that the compressed data in the file can be extracted for loading.

  • When unloading data, compresses the data file using the specified compression algorithm.

Values:

Supported Values

Notes

AUTO

When loading data, compression algorithm detected automatically, except for Brotli-compressed files, which cannot currently be detected automatically. When unloading data, files are automatically compressed using the default, which is gzip.

GZIP

BROTLI

Must be specified if loading/unloading Brotli-compressed files.

ZSTD

Zstandard v0.8 (and higher) is supported.

DEFLATE

Deflate-compressed files (with zlib header, RFC1950).

RAW_DEFLATE

Raw Deflate-compressed files (without header, RFC1951).

NONE

When loading data, indicates that the files have not been compressed. When unloading data, specifies that the unloaded files are not compressed.

Default:

AUTO.

Note

We recommend that you use the default AUTO option because it will determine both the file and codec compression. Specifying a compression option refers to the compression of files, not the compression of blocks (codecs).

TRIM_SPACE = TRUE | FALSE
Use:

Data loading only

Definition:

Boolean that specifies whether to remove leading and trailing white space from strings.

For example, if your external database software encloses fields in quotes, but inserts a leading space, Snowflake reads the leading space rather than the opening quotation character as the beginning of the field (i.e. the quotation marks are interpreted as part of the string of field data). Set this option to TRUE to remove undesirable spaces during the data load.

This file format option is applied to the following actions only when loading Avro data into separate columns using the MATCH_BY_COLUMN_NAME copy option.

Default:

FALSE

REPLACE_INVALID_CHARACTERS = TRUE | FALSE
Use:

Data loading and external table

Definition:

Boolean that specifies whether to replace invalid UTF-8 characters with the Unicode replacement character (). This option performs a one-to-one character replacement.

Values:

If set to TRUE, Snowflake replaces invalid UTF-8 characters with the Unicode replacement character.

If set to FALSE, the load operation produces an error when invalid UTF-8 character encoding is detected.

Default:

FALSE

NULL_IF = ( 'string1' [ , 'string2' , ... ] )
Use:

Data loading only

Definition:

String used to convert to and from SQL NULL. Snowflake replaces these strings in the data load source with SQL NULL. To specify more than one string, enclose the list of strings in parentheses and use commas to separate each value.

This file format option is applied to the following actions only when loading Avro data into separate columns using the MATCH_BY_COLUMN_NAME copy option.

Note that Snowflake converts all instances of the value to NULL, regardless of the data type. For example, if 2 is specified as a value, all instances of 2 as either a string or number are converted.

For example:

NULL_IF = ('\N', 'NULL', 'NUL', '')

Note that this option can include empty strings.

Default:

\\N (i.e. NULL, which assumes the ESCAPE_UNENCLOSED_FIELD value is \\)

TYPE = ORC

TRIM_SPACE = TRUE | FALSE
Use:

Data loading and external tables

Definition:

Boolean that specifies whether to remove leading and trailing white space from strings.

For example, if your external database software encloses fields in quotes, but inserts a leading space, Snowflake reads the leading space rather than the opening quotation character as the beginning of the field (i.e. the quotation marks are interpreted as part of the string of field data). Set this option to TRUE to remove undesirable spaces during the data load.

This file format option is applied to the following actions only when loading Orc data into separate columns using the MATCH_BY_COLUMN_NAME copy option.

Default:

FALSE

REPLACE_INVALID_CHARACTERS = TRUE | FALSE
Use:

Data loading and external table

Definition:

Boolean that specifies whether to replace invalid UTF-8 characters with the Unicode replacement character (). This option performs a one-to-one character replacement.

Values:

If set to TRUE, Snowflake replaces invalid UTF-8 characters with the Unicode replacement character.

If set to FALSE, the load operation produces an error when invalid UTF-8 character encoding is detected.

Default:

FALSE

NULL_IF = ( 'string1' [ , 'string2' , ... ] )
Use:

Data loading and external tables

Definition:

String used to convert to and from SQL NULL. Snowflake replaces these strings in the data load source with SQL NULL. To specify more than one string, enclose the list of strings in parentheses and use commas to separate each value.

This file format option is applied to the following actions only when loading Orc data into separate columns using the MATCH_BY_COLUMN_NAME copy option.

Note that Snowflake converts all instances of the value to NULL, regardless of the data type. For example, if 2 is specified as a value, all instances of 2 as either a string or number are converted.

For example:

NULL_IF = ('\N', 'NULL', 'NUL', '')

Note that this option can include empty strings.

Default:

\\N (i.e. NULL, which assumes the ESCAPE_UNENCLOSED_FIELD value is \\)

TYPE = PARQUET

COMPRESSION = AUTO | LZO | SNAPPY | NONE
Use:

Data loading, data unloading, and external tables

Definition:

  • When loading data, specifies the current compression algorithm for columns in the Parquet files.

  • When unloading data, compresses the data file using the specified compression algorithm.

Values:

Supported Values

Notes

AUTO

When loading data, compression algorithm detected automatically. Supports the following compression algorithms: Brotli, gzip, Lempel-Ziv-Oberhumer (LZO), LZ4, Snappy, or Zstandard v0.8 (and higher). . When unloading data, unloaded files are compressed using the Snappy compression algorithm by default.

LZO

When unloading data, files are compressed using the Snappy algorithm by default. If unloading data to LZO-compressed files, specify this value.

SNAPPY

When unloading data, files are compressed using the Snappy algorithm by default. You can optionally specify this value.

NONE

When loading data, indicates that the files have not been compressed. When unloading data, specifies that the unloaded files are not compressed.

Default:

AUTO

SNAPPY_COMPRESSION = TRUE | FALSE
Use:

Data unloading only

Supported Values

Notes

AUTO

Unloaded files are compressed using the Snappy compression algorithm by default.

SNAPPY

May be specified if unloading Snappy-compressed files.

NONE

When loading data, indicates that the files have not been compressed. When unloading data, specifies that the unloaded files are not compressed.

Definition:

Boolean that specifies whether unloaded file(s) are compressed using the SNAPPY algorithm.

Note

Deprecated. Use COMPRESSION = SNAPPY instead.

Limitations:

Only supported for data unloading operations.

Default:

TRUE

BINARY_AS_TEXT = TRUE | FALSE
Use:

Data loading and external tables

Definition:

Boolean that specifies whether to interpret columns with no defined logical data type as UTF-8 text. When set to FALSE, Snowflake interprets these columns as binary data.

Default:

TRUE

Note

Snowflake recommends that you set BINARY_AS_TEXT to FALSE to avoid any potential conversion issues.

TRIM_SPACE = TRUE | FALSE
Use:

Data loading only

Definition:

Boolean that specifies whether to remove leading and trailing white space from strings.

For example, if your external database software encloses fields in quotes, but inserts a leading space, Snowflake reads the leading space rather than the opening quotation character as the beginning of the field (i.e. the quotation marks are interpreted as part of the string of field data). Set this option to TRUE to remove undesirable spaces during the data load.

This file format option is applied to the following actions only when loading Parquet data into separate columns using the MATCH_BY_COLUMN_NAME copy option.

Default:

FALSE

USE_LOGICAL_TYPE = TRUE | FALSE
Use:

Data loading, data querying in staged files, and schema detection.

Definition:

Boolean that specifies whether to use Parquet logical types. With this file format option, Snowflake can interpret Parquet logical types during data loading. For more information, see Parquet Logical Type Definitions. To enable Parquet logical types, set USE_LOGICAL_TYPE as TRUE when you create a new file format option.

Limitations:

Not supported for data unloading.

REPLACE_INVALID_CHARACTERS = TRUE | FALSE
Use:

Data loading and external table

Definition:

Boolean that specifies whether to replace invalid UTF-8 characters with the Unicode replacement character (). This option performs a one-to-one character replacement.

Values:

If set to TRUE, Snowflake replaces invalid UTF-8 characters with the Unicode replacement character.

If set to FALSE, the load operation produces an error when invalid UTF-8 character encoding is detected.

Default:

FALSE

NULL_IF = ( 'string1' [ , 'string2' , ... ] )
Use:

Data loading only

Definition:

String used to convert to and from SQL NULL. Snowflake replaces these strings in the data load source with SQL NULL. To specify more than one string, enclose the list of strings in parentheses and use commas to separate each value.

This file format option is applied to the following actions only when loading Parquet data into separate columns using the MATCH_BY_COLUMN_NAME copy option.

Note that Snowflake converts all instances of the value to NULL, regardless of the data type. For example, if 2 is specified as a value, all instances of 2 as either a string or number are converted.

For example:

NULL_IF = ('\N', 'NULL', 'NUL', '')

Note that this option can include empty strings.

Default:

\\N (i.e. NULL, which assumes the ESCAPE_UNENCLOSED_FIELD value is \\)

TYPE = XML

COMPRESSION = AUTO | GZIP | BZ2 | BROTLI | ZSTD | DEFLATE | RAW_DEFLATE | NONE
Use:

Data loading only

Definition:
  • When loading data, specifies the current compression algorithm for the data file. Snowflake uses this option to detect how an already-compressed data file was compressed so that the compressed data in the file can be extracted for loading.

  • When unloading data, compresses the data file using the specified compression algorithm.

Values:

Supported Values

Notes

AUTO

When loading data, compression algorithm detected automatically, except for Brotli-compressed files, which cannot currently be detected automatically. When unloading data, files are automatically compressed using the default, which is gzip.

GZIP

BZ2

BROTLI

Must be specified if loading/unloading Brotli-compressed files.

ZSTD

Zstandard v0.8 (and higher) is supported.

DEFLATE

Deflate-compressed files (with zlib header, RFC1950).

RAW_DEFLATE

Raw Deflate-compressed files (without header, RFC1951).

NONE

When loading data, indicates that the files have not been compressed. When unloading data, specifies that the unloaded files are not compressed.

Default:

AUTO

IGNORE_UTF8_ERRORS = TRUE | FALSE
Use:

Data loading and external table

Definition:

Boolean that specifies whether UTF-8 encoding errors produce error conditions. It is an alternative syntax for REPLACE_INVALID_CHARACTERS.

Values:

If set to TRUE, any invalid UTF-8 sequences are silently replaced with the Unicode character U+FFFD (i.e. “replacement character”).

If set to FALSE, the load operation produces an error when invalid UTF-8 character encoding is detected.

Default:

FALSE

PRESERVE_SPACE = TRUE | FALSE
Use:

Data loading only

Definition:

Boolean that specifies whether the XML parser preserves leading and trailing spaces in element content.

Default:

FALSE

STRIP_OUTER_ELEMENT = TRUE | FALSE
Use:

Data loading only

Definition:

Boolean that specifies whether the XML parser strips out the outer XML element, exposing 2nd level elements as separate documents.

Default:

FALSE

DISABLE_SNOWFLAKE_DATA = TRUE | FALSE
Use:

Data loading only

Definition:

Boolean that specifies whether the XML parser disables recognition of Snowflake semi-structured data tags.

Default:

FALSE

DISABLE_AUTO_CONVERT = TRUE | FALSE
Use:

Data loading only

Definition:

Boolean that specifies whether the XML parser disables automatic conversion of numeric and Boolean values from text to native representation.

Default:

FALSE

REPLACE_INVALID_CHARACTERS = TRUE | FALSE
Use:

Data loading and external table

Definition:

Boolean that specifies whether to replace invalid UTF-8 characters with the Unicode replacement character (). This option performs a one-to-one character replacement.

Values:

If set to TRUE, Snowflake replaces invalid UTF-8 characters with the Unicode replacement character.

If set to FALSE, the load operation produces an error when invalid UTF-8 character encoding is detected.

Default:

FALSE

SKIP_BYTE_ORDER_MARK = TRUE | FALSE
Use:

Data loading only

Definition:

Boolean that specifies whether to skip any BOM (byte order mark) present in an input file. A BOM is a character code at the beginning of a data file that defines the byte order and encoding form.

If set to FALSE, Snowflake recognizes any BOM in data files, which could result in the BOM either causing an error or being merged into the first column in the table.

Default:

TRUE

Usage Notes

  • ALTER FILE FORMAT does not support the following actions:

    • Changing the type (CSV, JSON, etc.) for the file format.

    • Unsetting any format options (i.e. resetting the options to the defaults for the type).

    • Unsetting (i.e. removing) a comment.

    To make any of these changes, you must recreate the file format.

Examples

Rename file format my_format to my_new_format:

ALTER FILE FORMAT IF EXISTS my_format RENAME TO my_new_format;
Copy

Specify comma (,) as the field delimiter for my_format (created in the CREATE FILE FORMAT examples):

ALTER FILE FORMAT my_format SET FIELD_DELIMITER=',';
Copy