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81be9ae60e
The option "fields optionally enclosed by" was missing a way to easily specify a single quote as the quoting character. Add '\'' to the existing solution '0x27' which isn't as friendly. See #705.
244 lines
8.5 KiB
ReStructuredText
244 lines
8.5 KiB
ReStructuredText
Loading CSV data
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================
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This command instructs pgloader to load data from a `CSV` file. Here's an
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example::
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LOAD CSV
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FROM 'GeoLiteCity-Blocks.csv' WITH ENCODING iso-646-us
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HAVING FIELDS
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(
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startIpNum, endIpNum, locId
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)
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INTO postgresql://user@localhost:54393/dbname
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TARGET TABLE geolite.blocks
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TARGET COLUMNS
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(
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iprange ip4r using (ip-range startIpNum endIpNum),
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locId
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)
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WITH truncate,
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skip header = 2,
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fields optionally enclosed by '"',
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fields escaped by backslash-quote,
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fields terminated by '\t'
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SET work_mem to '32 MB', maintenance_work_mem to '64 MB';
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The `csv` format command accepts the following clauses and options.
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CSV Source Specification: FROM
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------------------------------
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Filename where to load the data from. Accepts an *ENCODING* option. Use the
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`--list-encodings` option to know which encoding names are supported.
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The filename may be enclosed by single quotes, and could be one of the
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following special values:
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- *inline*
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The data is found after the end of the parsed commands. Any number
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of empty lines between the end of the commands and the beginning of
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the data is accepted.
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- *stdin*
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Reads the data from the standard input stream.
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- *FILENAMES MATCHING*
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The whole *matching* clause must follow the following rule::
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[ ALL FILENAMES | [ FIRST ] FILENAME ]
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MATCHING regexp
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[ IN DIRECTORY '...' ]
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The *matching* clause applies given *regular expression* (see above
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for exact syntax, several options can be used here) to filenames.
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It's then possible to load data from only the first match of all of
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them.
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The optional *IN DIRECTORY* clause allows specifying which directory
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to walk for finding the data files, and can be either relative to
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where the command file is read from, or absolute. The given
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directory must exists.
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Fields Specifications
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---------------------
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The *FROM* option also supports an optional comma separated list of *field*
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names describing what is expected in the `CSV` data file, optionally
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introduced by the clause `HAVING FIELDS`.
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Each field name can be either only one name or a name following with
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specific reader options for that field, enclosed in square brackets and
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comma-separated. Supported per-field reader options are:
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- *terminated by*
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See the description of *field terminated by* below.
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The processing of this option is not currently implemented.
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- *date format*
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When the field is expected of the date type, then this option allows
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to specify the date format used in the file.
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Date format string are template strings modeled against the
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PostgreSQL `to_char` template strings support, limited to the
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following patterns:
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- YYYY, YYY, YY for the year part
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- MM for the numeric month part
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- DD for the numeric day part
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- HH, HH12, HH24 for the hour part
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- am, AM, a.m., A.M.
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- pm, PM, p.m., P.M.
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- MI for the minutes part
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- SS for the seconds part
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- MS for the milliseconds part (4 digits)
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- US for the microseconds part (6 digits)
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- unparsed punctuation signs: - . * # @ T / \ and space
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Here's an example of a *date format* specification::
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column-name [date format 'YYYY-MM-DD HH24-MI-SS.US']
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- *null if*
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This option takes an argument which is either the keyword *blanks*
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or a double-quoted string.
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When *blanks* is used and the field value that is read contains
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only space characters, then it's automatically converted to an SQL
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`NULL` value.
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When a double-quoted string is used and that string is read as the
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field value, then the field value is automatically converted to an
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SQL `NULL` value.
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- *trim both whitespace*, *trim left whitespace*, *trim right whitespace*
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This option allows to trim whitespaces in the read data, either from
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both sides of the data, or only the whitespace characters found on
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the left of the streaing, or only those on the right of the string.
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CSV Loading Options: WITH
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-------------------------
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When loading from a `CSV` file, the following options are supported:
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- *truncate*
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When this option is listed, pgloader issues a `TRUNCATE` command
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against the PostgreSQL target table before reading the data file.
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- *drop indexes*
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When this option is listed, pgloader issues `DROP INDEX` commands
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against all the indexes defined on the target table before copying
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the data, then `CREATE INDEX` commands once the `COPY` is done.
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In order to get the best performance possible, all the indexes are
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created in parallel and when done the primary keys are built again
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from the unique indexes just created. This two step process allows
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creating the primary key index in parallel with the other indexes,
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as only the `ALTER TABLE` command needs an *access exclusive lock*
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on the target table.
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- *disable triggers*
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When this option is listed, pgloader issues an `ALTER TABLE ...
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DISABLE TRIGGER ALL` command against the PostgreSQL target table
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before copying the data, then the command `ALTER TABLE ... ENABLE
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TRIGGER ALL` once the `COPY` is done.
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This option allows loading data into a pre-existing table ignoring
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the *foreign key constraints* and user defined triggers and may
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result in invalid *foreign key constraints* once the data is loaded.
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Use with care.
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- *skip header*
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Takes a numeric value as argument. Instruct pgloader to skip that
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many lines at the beginning of the input file.
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- *csv header*
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Use the first line read after *skip header* as the list of csv field
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names to be found in the CSV file, using the same CSV parameters as
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for the CSV data.
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- *trim unquoted blanks*
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When reading unquoted values in the `CSV` file, remove the blanks
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found in between the separator and the value. That behaviour is the
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default.
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- *keep unquoted blanks*
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When reading unquoted values in the `CSV` file, keep blanks found in
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between the separator and the value.
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- *fields optionally enclosed by*
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Takes a single character as argument, which must be found inside single
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quotes, and might be given as the printable character itself, the
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special value \t to denote a tabulation character, the special value \'
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to denote a single-quote, or `0x` then an hexadecimal value read as the
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ASCII code for the character.
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The following options specify the same enclosing character, a single quote::
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fields optionally enclosed by '\''
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fields optionally enclosed by '0x27'
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This character is used as the quoting character in the `CSV` file,
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and defaults to double-quote.
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- *fields not enclosed*
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By default, pgloader will use the double-quote character as the
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enclosing character. If you have a CSV file where fields are not
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enclosed and are using double-quote as an expected ordinary
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character, then use the option *fields not enclosed* for the CSV
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parser to accept those values.
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- *fields escaped by*
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Takes either the special value *backslash-quote* or *double-quote*,
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or any value supported by the *fields terminated by* option (see
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below). This value is used to recognize escaped field separators
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when they are to be found within the data fields themselves.
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Defaults to *double-quote*.
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- *csv escape mode*
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Takes either the special value *quote* (the default) or *following*
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and allows the CSV parser to parse either only escaped field
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separator or any character (including CSV data) when using the
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*following* value.
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- *fields terminated by*
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Takes a single character as argument, which must be found inside
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single quotes, and might be given as the printable character itself,
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the special value \t to denote a tabulation character, or `0x` then
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an hexadecimal value read as the ASCII code for the character.
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This character is used as the *field separator* when reading the
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`CSV` data.
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- *lines terminated by*
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Takes a single character as argument, which must be found inside
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single quotes, and might be given as the printable character itself,
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the special value \t to denote a tabulation character, or `0x` then
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an hexadecimal value read as the ASCII code for the character.
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This character is used to recognize *end-of-line* condition when
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reading the `CSV` data.
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