diff options
| -rw-r--r-- | doc/src/sgml/ref/copy.sgml | 13 |
1 files changed, 8 insertions, 5 deletions
diff --git a/doc/src/sgml/ref/copy.sgml b/doc/src/sgml/ref/copy.sgml index ff91ee2d9f7..79ed7c204e3 100644 --- a/doc/src/sgml/ref/copy.sgml +++ b/doc/src/sgml/ref/copy.sgml @@ -1,5 +1,5 @@ <!-- -$PostgreSQL: pgsql/doc/src/sgml/ref/copy.sgml,v 1.88 2009/09/17 21:13:01 momjian Exp $ +$PostgreSQL: pgsql/doc/src/sgml/ref/copy.sgml,v 1.89 2009/09/17 21:49:15 momjian Exp $ PostgreSQL documentation --> @@ -550,10 +550,13 @@ COPY <replaceable class="parameter">count</replaceable> <para> The <literal>CSV</> format has no standard way to distinguish a <literal>NULL</> value from an empty string. - <productname>PostgreSQL</>'s <command>COPY</> handles this using - quoting. A <literal>NULL</> is output as an empty string without - quotes, while an empty string data value is double-quoted - (<literal>""</>). Reading values follows similar rules. You can + <productname>PostgreSQL</>'s <command>COPY</> handles this by + quoting. A <literal>NULL</> is output as the <literal>NULL</> + parameter and is not quoted, while a non-NULL value matching the + the <literal>NULL</> parameter string is quoted. Therefore, using the default + settings, a <literal>NULL</> is written as an unquoted empty + string, while an empty string data value is written with double quotes + (<literal>""</>). Reading values follows similar rules. You can use <literal>FORCE NOT NULL</> to prevent <literal>NULL</> input comparisons for specific columns. </para> |