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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML
><HEAD
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>Character Types</TITLE
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><H1
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><A
NAME="AEN833"
>Character Types</A
></H1
><P
><SPAN
CLASS="ACRONYM"
>SQL92</SPAN
> defines two primary character types:
<SPAN
CLASS="TYPE"
>char</SPAN
> and <SPAN
CLASS="TYPE"
>varchar</SPAN
>.
<SPAN
CLASS="PRODUCTNAME"
>Postgres</SPAN
> supports these types, in
addition to the more general <SPAN
CLASS="TYPE"
>text</SPAN
> type,
which unlike <SPAN
CLASS="TYPE"
>varchar</SPAN
>
does not require an upper
limit to be declared on the size of the field.</P
><P
><DIV
CLASS="TABLE"
><P
><B
>Table 5-5. <SPAN
CLASS="PRODUCTNAME"
>Postgres</SPAN
> Character Types</B
></P
><TABLE
BORDER="1"
CLASS="CALSTABLE"
><TR
><TH
ALIGN="LEFT"
VALIGN="TOP"
>Character Type</TH
><TH
ALIGN="LEFT"
VALIGN="TOP"
>Storage</TH
><TH
ALIGN="LEFT"
VALIGN="TOP"
>Recommendation</TH
><TH
ALIGN="LEFT"
VALIGN="TOP"
>Description</TH
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
>char</TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>1 byte</TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
><SPAN
CLASS="ACRONYM"
>SQL92</SPAN
>-compatible</TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Single character</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
>char(n)</TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>(4+n) bytes</TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
><SPAN
CLASS="ACRONYM"
>SQL92</SPAN
>-compatible</TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Fixed-length blank padded</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
>text</TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>(4+x) bytes</TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Best choice</TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Variable-length</TD
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
>varchar(n)</TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>(4+n) bytes</TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
><SPAN
CLASS="ACRONYM"
>SQL92</SPAN
>-compatible</TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Variable-length with limit</TD
></TR
></TABLE
></DIV
></P
><P
>There is one other fixed-length character type.
The <SPAN
CLASS="TYPE"
>name</SPAN
> type
only has one purpose and that is to provide
<SPAN
CLASS="PRODUCTNAME"
>Postgres</SPAN
> with a
special type to use for internal names.
It is not intended for use by the general user.
It's length is currently defined as 32 chars
but should be reference using NAMEDATALEN.
This is set at compile time and may change in a future release.</P
><P
><DIV
CLASS="TABLE"
><P
><B
>Table 5-6. <SPAN
CLASS="PRODUCTNAME"
>Postgres</SPAN
> Specialty Character Type</B
></P
><TABLE
BORDER="1"
CLASS="CALSTABLE"
><TR
><TH
ALIGN="LEFT"
VALIGN="TOP"
>Character Type</TH
><TH
ALIGN="LEFT"
VALIGN="TOP"
>Storage</TH
><TH
ALIGN="LEFT"
VALIGN="TOP"
>Description</TH
></TR
><TR
><TD
ALIGN="LEFT"
VALIGN="TOP"
>name</TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>32 bytes</TD
><TD
ALIGN="LEFT"
VALIGN="TOP"
>Thirty-two character internal type</TD
></TR
></TABLE
></DIV
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