From: Bruce Momjian Date: Thu, 17 Sep 2009 21:28:30 +0000 (+0000) Subject: CVS NULL Documentation X-Git-Tag: REL8_4_2~62 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=77b2388b2417d80505db67a81f773cf80e2d9529;p=thirdparty%2Fpostgresql.git CVS NULL Documentation Clearify documentation of CVS's output of NULL values, per suggestion from Magnus. Backpatch to 8.4.X. --- diff --git a/doc/src/sgml/ref/copy.sgml b/doc/src/sgml/ref/copy.sgml index e7f76d3e581..238397828fe 100644 --- a/doc/src/sgml/ref/copy.sgml +++ b/doc/src/sgml/ref/copy.sgml @@ -1,5 +1,5 @@ @@ -541,16 +541,13 @@ COPY count non-NULL values in specific columns. - + The CSV format has no standard way to distinguish a NULL value from an empty string. - PostgreSQL's COPY handles this by - quoting. A NULL is output as the NULL - string and is not quoted, while a data value matching the - NULL string is quoted. Therefore, using the default - settings, a NULL is written as an unquoted empty - string, while an empty string is written with double quotes - (""). Reading values follows similar rules. You can + PostgreSQL's COPY handles this using + quoting. A NULL is output as an empty string without + quotes, while an empty string data value is double-quoted + (""). Reading values follows similar rules. You can use FORCE NOT NULL to prevent NULL input comparisons for specific columns.