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authorBruce Momjian2009-09-17 21:13:01 +0000
committerBruce Momjian2009-09-17 21:13:01 +0000
commitc66244ad99c484da085cd23b24fab11a9567bc02 (patch)
tree91b4a4c24171011809dfd157f35092c4c9f30be1
parent03c08256812b7e1f7ee6bee98eb38442e65d765c (diff)
CVS NULL Documentation
Clearify documentation of CVS's output of NULL values, per suggestion from Magnus. Backpatch to 8.4.X.
-rw-r--r--doc/src/sgml/ref/copy.sgml11
1 files changed, 4 insertions, 7 deletions
diff --git a/doc/src/sgml/ref/copy.sgml b/doc/src/sgml/ref/copy.sgml
index 0821818310..a89f33eb5a 100644
--- a/doc/src/sgml/ref/copy.sgml
+++ b/doc/src/sgml/ref/copy.sgml
@@ -550,13 +550,10 @@ 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 by
- quoting. A <literal>NULL</> is output as the <literal>NULL</>
- string and is not quoted, while a data value matching the
- <literal>NULL</> string is quoted. Therefore, using the default
- settings, a <literal>NULL</> is written as an unquoted empty
- string, while an empty string is written with double quotes
- (<literal>""</>). Reading values follows similar rules. You can
+ <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
use <literal>FORCE NOT NULL</> to prevent <literal>NULL</> input
comparisons for specific columns.
</para>