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@ -1,5 +1,5 @@ |
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<!-- |
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$PostgreSQL: pgsql/doc/src/sgml/ref/copy.sgml,v 1.89 2009/09/17 21:49:15 momjian Exp $ |
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$PostgreSQL: pgsql/doc/src/sgml/ref/copy.sgml,v 1.90 2009/09/18 20:01:13 tgl Exp $ |
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PostgreSQL documentation |
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--> |
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@ -183,8 +183,8 @@ COPY { <replaceable class="parameter">tablename</replaceable> [ ( <replaceable c |
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<listitem> |
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<para> |
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The string that represents a null value. The default is |
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<literal>\N</literal> (backslash-N) in text mode, and a empty |
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value with no quotes in <literal>CSV</> mode. You might prefer an |
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<literal>\N</literal> (backslash-N) in text mode, and an unquoted empty |
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string in <literal>CSV</> mode. You might prefer an |
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empty string even in text mode for cases where you don't want to |
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distinguish nulls from empty strings. |
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</para> |
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@ -249,8 +249,7 @@ COPY { <replaceable class="parameter">tablename</replaceable> [ ( <replaceable c |
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In <literal>CSV</> <command>COPY TO</> mode, forces quoting to be |
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used for all non-<literal>NULL</> values in each specified column. |
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<literal>NULL</> output is never quoted. If <literal>*</> is specified, |
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non-<literal>NULL</> values for all columns of the table will be |
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quoted. |
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non-<literal>NULL</> values will be quoted in all columns. |
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</para> |
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</listitem> |
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</varlistentry> |
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@ -550,11 +549,11 @@ COPY <replaceable class="parameter">count</replaceable> |
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<para> |
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The <literal>CSV</> format has no standard way to distinguish a |
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<literal>NULL</> value from an empty string. |
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<productname>PostgreSQL</>'s <command>COPY</> handles this by |
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quoting. A <literal>NULL</> is output as the <literal>NULL</> |
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parameter and is not quoted, while a non-NULL value matching the |
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the <literal>NULL</> parameter string is quoted. Therefore, using the default |
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settings, a <literal>NULL</> is written as an unquoted empty |
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<productname>PostgreSQL</>'s <command>COPY</> handles this by quoting. |
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A <literal>NULL</> is output as the <literal>NULL</> parameter string |
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and is not quoted, while a non-<literal>NULL</> value matching the |
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<literal>NULL</> parameter string is quoted. For example, with the |
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default settings, a <literal>NULL</> is written as an unquoted empty |
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string, while an empty string data value is written with double quotes |
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(<literal>""</>). Reading values follows similar rules. You can |
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use <literal>FORCE NOT NULL</> to prevent <literal>NULL</> input |
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