diff options
author | Bruce Momjian | 2009-09-17 21:49:15 +0000 |
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committer | Bruce Momjian | 2009-09-17 21:49:15 +0000 |
commit | 2aa5405e323ce29c03148d4f7f7ae0e1e7471112 (patch) | |
tree | eb13462fd1648f3d7136a0d5e48daf1b0cb9b09a | |
parent | 20227781555cf6698ea6d1ad24ec6cc7b1aed15d (diff) |
CSV NULL Documentation
Update docs to clearly explain NULL value matching behavior, per Andrew.
Backpatch to 8.4.X.
-rw-r--r-- | doc/src/sgml/ref/copy.sgml | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/doc/src/sgml/ref/copy.sgml b/doc/src/sgml/ref/copy.sgml index a89f33eb5a..859b0f924d 100644 --- a/doc/src/sgml/ref/copy.sgml +++ b/doc/src/sgml/ref/copy.sgml @@ -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> |