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>' ] }
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
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 formdb_name.schema_name.object_name
orschema_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 by0x
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 by0x
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]
, wherecompression
is the extension added by the compression method, ifCOMPRESSION
is set.
Note
If the
SINGLE
copy option isTRUE
, 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 theinternal_location
orexternal_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
orRECORD_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 theRECORD_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 toNONE
.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, assumingFIELD_DELIMITER = '|'
andFIELD_OPTIONALLY_ENCLOSED_BY = '"'
:|"Hello world"| /* loads as */ >Hello world< |" Hello world "| /* loads as */ > Hello world < | "Hello world" | /* loads as */ >Hello world<
(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 (''
).When a field contains this character, escape it using the same character. For example, if the value is the double quote character and a field contains the string
A "B" C
, escape the double quotes 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 of2
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 theESCAPE_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
. WhenFIELD_OPTIONALLY_ENCLOSED_BY = NONE
, settingEMPTY_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
ValueSupported 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 of2
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 theESCAPE_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]
, wherecompression
is the extension added by the compression method, ifCOMPRESSION
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 toTRUE
: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 characterU+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 of2
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 theESCAPE_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 of2
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 theESCAPE_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 of2
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 theESCAPE_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 characterU+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;
Specify comma (,
) as the field delimiter for my_format
(created in the CREATE FILE FORMAT examples):
ALTER FILE FORMAT my_format SET FIELD_DELIMITER=',';