metakit for tcl.mht

TCL的数据库处理支撑库及一些示例

  <P></P>
  <DT>EXAMPLES
  <DD>Define a cursor pointing to a new empty row: <PRE>    set cursor =
[mk::row create]</PRE>Initialize a temporary view with 100=20
  copies of the string "Hello": <PRE>    mk::cursor create cursor=20
    mk::row insert $cursor 100 [mk::row create text "Hello"]</PRE>
  <P>
  <P></P>
  <DT><A name=3Dmk_get>
  <HR SIZE=3D1>
  </A>
  <H2>mk::get</H2>
  <DD>
  <H3>Fetch values</H3>
  <P></P>
  <DT>SYNOPSIS
  <DD><B>mk::get</B> &nbsp;<I>cursor</I> &nbsp;?-size?<BR><B>mk::get</B> =

  &nbsp;<I>cursor</I> &nbsp;?-size? &nbsp;<I>prop</I> &nbsp;<I>...</I>=20
&nbsp;<BR>
  <P></P>
  <DT>DESCRIPTION
  <DD>The <B>mk::get</B> command fetches values from the row specified =
by=20
  <I>cursor</I>.=20
  <P>Without argument, <I>get</I> returns a list of <I>'prop1 value1 =
prop2=20
  value2 ...'</I>. This format is most convenient for setting an array =
variable,=20
  as the following example illustrates: <PRE>    array set v [mk::get =
db.phonebook!0]
    parray v</PRE>Note that the <I>cursor</I> argument can be the value =
of a=20
  cursor variable, or it can be synthesized on the spot, as in the above =

  example.=20
  <P>If the <B>-size</B> option is specified, the size of property =
values is=20
  returned instead of their contents. This is normally in bytes, but for =

  integers it can be a negative value indicating the number of bits used =
to=20
  store ints (-1, -2, or -4). This is an efficient way to determine the =
sizes of=20
  property values without fetching them.=20
  <P>If arguments are specified in the <I>get</I> command, they are =
interpreted=20
  as property names and a list will be returned containing the values of =
these=20
  properties in the specified order.=20
  <P>If <I>cursor</I> does not point to a valid row, default values are =
returned=20
  instead (no properties, and empty strings or numeric zero's, according =
to the=20
  property types).=20
  <P>
  <P></P>
  <DT>EXAMPLES
  <DD>Set up an array containing all the fields in the third row: <PRE>  =
  array set fields [mk::get db.phonebook!2]</PRE>Created a line with=20
  some formatted fields: <PRE>    puts [eval [list format {%-20s %d}] =
[mk::get db.phonebook!2 name date]]</PRE>
  <P>
  <P></P>
  <DT><A name=3Dmk_set>
  <HR SIZE=3D1>
  </A>
  <H2>mk::set</H2>
  <DD>
  <H3>Store values</H3>
  <P></P>
  <DT>SYNOPSIS
  <DD><B>mk::set</B> &nbsp;<I>cursor</I> &nbsp;<I>?prop</I> =
&nbsp;<I>value</I>=20
  &nbsp;<I>...?</I> &nbsp;<BR>
  <P></P>
  <DT>DESCRIPTION
  <DD>The <B>mk::set</B> command stores values into the row specified by =

  <I>cursor</I>.=20
  <P>If a property is specified which does not exist, it will be =
appended as a=20
  new definition for the containing view. As an important side effect, =
all other=20
  rows in this view will now also have such a property, with an =
appropriate=20
  default value for the property. Note that when new properties are =
defined in=20
  this way, they will be created as string properties unless qualified =
by a type=20
  suffix (see <I>'mk::view layout'</I> for details on property types and =
their=20
  default values).=20
  <P>Using <I>mk::set</I> command without specifying properties returns =
the=20
  current value and is identical to <I>mk::get</I>.=20
  <P>If <I>cursor</I> points to a non-existent row past the end of the =
view, an=20
  appropriate number of empty rows will be inserted first.=20
  <P>
  <P></P>
  <DT><A name=3Dmk_loop>
  <HR SIZE=3D1>
  </A>
  <H2>mk::loop</H2>
  <DD>
  <H3>Iterate over the rows of a view</H3>
  <P></P>
  <DT>SYNOPSIS
  <DD><B>mk::loop</B> &nbsp;<I>cursorName</I> &nbsp;<I>{body}</I>=20
  &nbsp;<BR><B>mk::loop</B> &nbsp;<I>cursorName</I> &nbsp;<I>path</I>=20
  &nbsp;<I>{body}</I> &nbsp;<BR><B>mk::loop</B> &nbsp;<I>cursorName</I>=20
  &nbsp;<I>path</I> &nbsp;<I>first</I> &nbsp;<I>?limit?</I> =
&nbsp;<I>?step?</I>=20
  &nbsp;<I>{body}</I> &nbsp;<BR>
  <P></P>
  <DT>DESCRIPTION
  <DD>The <B>mk::loop</B> command offers a convenient way to iterate =
over the=20
  rows of a view. Iteration can be restricted to a certain range, and =
can=20
  optionally use a forward or backward step. This is a convenience =
function=20
  which is more efficient than performing explicit iteration over an =
index and=20
  positioning a cursor.=20
  <P>When called with just a <I>path</I> argument, the loop will iterate =
over=20
  all the rows in the corresponding view. The <I>cursorName</I> loop =
variable=20
  will be set (or reset) on each iteration, and is created if it did not =
yet=20
  exist.=20
  <P>When <I>path</I> is not specified, the <I>cursorName</I> variable =
must=20
  exist and be a valid cursor, although its current position will be =
ignored.=20
  The command <I>'mk::loop X {...}'</I> is identical to <I>'mk::loop X =
$X=20
  {...}'</I>.=20
  <P>The <I>first</I> argument specifies the first index position to use =

  (default 0), the <I>limit</I> argument specifies the last argument =
(default=20
  'end'), and the <I>step</I> argument specifies the increment (default =
1). If=20
  <I>step</I> is negative and <I>limit</I> exceeds <I>first</I>, then =
the loop=20
  body will never be executed. A zero <I>step</I> value can lead to =
infinite=20
  looping unless the <I>break</I> command is called inside the loop.=20
  <P>The <I>first</I>, <I>limit</I>, and <I>step</I> arguments may be =
arbitrary=20
  integer expressions and are evaluated exactly once when the loop is =
entered.=20
  <P>Note that you cannot easily use a loop to insert or delete rows, =
since=20
  changes to views do not adjust cursors pointing into that view. =
Instead, you=20
  can use tricks like moving backwards (for deletions), or splitting the =
work=20
  into two separate passes.=20
  <P></P>
  <DT><A name=3Dmk_elect>
  <HR SIZE=3D1>
  </A>
  <H2>mk::select</H2>
  <DD>
  <H3>Selection and sorting</H3>
  <P></P>
  <DT>SYNOPSIS
  <DD><B>mk::select</B> &nbsp;<I>path</I> &nbsp;<I>?options</I>=20
  &nbsp;<I>...?</I> &nbsp;<BR>
  <P></P>
  <DT>DESCRIPTION
  <DD>The <B>mk::select</B> command combines a flexible selection =
operation with=20
  a way to sort the resulting set of rows. The result is a list of row =
index=20
  numbers (possibly empty), which can be used to reposition a cursor and =
to=20
  address rows directly.=20
  <P>A selection is specified using any combination of these criteria:=20
  <UL>
    <DL>
      <DT><I>prop</I> <I>value</I>=20
      <DD>Numeric or case-insensitive match=20
      <DT><B>-min</B> <I>prop</I> <I>value</I>=20
      <DD>Property must be greater or equal to value (case is ignored)=20
      <DT><B>-max</B> <I>prop</I> <I>value</I>=20
      <DD>Property must be less or equal to value (case is ignored)=20
      <DT><B>-exact</B> <I>prop</I> <I>value</I>=20
      <DD>Exact case-sensitive string match=20
      <DT><B>-glob</B> <I>prop</I> <I>pattern</I>=20
      <DD>Match "glob-style" expression wildcard=20
      <DT><B>-globnc</B> <I>prop</I> <I>pattern</I>=20
      <DD>Match "glob-style" expression, ignoring case=20
      <DT><B>-regexp</B> <I>prop</I> <I>pattern</I>=20
      <DD>Match specified regular expression=20
      <DT><B>-keyword</B> <I>prop</I> <I>word</I>=20
      <DD>Match word as free text or partial prefix </DD></DL></UL>If =
multiple=20
  criteria are specified, then selection succeeds only if all criteria =
are=20
  satisfied. If <I>prop</I> is a list, selection succeeds if <I>any</I> =
of the=20
  given properties satisfies the corresponding match.=20
  <P>Optional selection constraints:=20
  <UL>
    <DL>
      <DT><B>-first</B> <I>pos</I>=20
      <DD>Selection starts at specified row index=20
      <DT><B>-count</B> <I>num</I>=20
      <DD>Return no more than this many results </DD></DL></UL>Note: not =
yet very=20
  useful with sorting, which is done after these constraints have been =
applied.=20
  <P>To sort the set of rows (with or without preliminary selection), =
use:=20
  <UL>
    <DL>
      <DT><B>-sort</B> <I>prop</I> <BR><B>-sort</B> {<I>prop</I> ...}=20
      <DD>Sort on one or more properties, ascending=20
      <DT><B>-rsort</B> <I>prop</I> <BR><B>-rsort</B> {<I>prop</I> ...}=20
      <DD>Sort on one or more properties, descending =
</DD></DL></UL>Multiple sort=20
  options are combined in the order given.=20
  <P>
  <P></P>
  <DT>EXAMPLES
  <DD>Select a range of entries: <PRE>    foreach i [mk::select =
db.phonebook -min date 19980101 -max date 19980131] {
        puts "Dated Jan 1998: [mk::get db.phonebook!$i name]"
    }</PRE>Search for a unique match (<I>'-count 2'</I> speeds up =
selection=20
  when many entries match): <PRE>    set v [mk::select db.phonebook =
-count 2 -glob name "John*"]
    switch [llength $v] {
        0       {puts "not found"}
        1       {puts "found: [mk::get db.phonebook![lindex $v 0] =
name]"}
        2       {puts "there is more than one entry matching 'John*'"}
    }</PRE>Sort by descending date and by ascending name: <PRE>    =
foreach i [mk::select db.phonebook -rsort date -sort name] {
        puts "Change log: [mk::get db.phonebook!$i date name]"
    }</PRE>
  <P>
  <P></P>
  <DT><A name=3Dmk_channel>
  <HR SIZE=3D1>
  </A>
  <H2>mk::channel</H2>
  <DD>
  <H3>Channel interface</H3>
  <P></P>
  <DT>SYNOPSIS
  <DD><B>mk::channel</B> &nbsp;<I>path</I> &nbsp;<I>prop</I> =
&nbsp;<I>?mode?</I>=20
  &nbsp;<BR>
  <P></P>
  <DT>DESCRIPTION
  <DD>The <B>mk::channel</B> command provides a channel interface to =
binary=20
  fields. It needs the <I>path</I> of a row and the name of a binary=20
  <I>prop</I>, and returns a channel descriptor which can be used to =
read or=20
  write from.=20
  <P>Channels are opened in one of three modes:=20
  <BLOCKQUOTE><B>read</B> - <I>open for reading existing contents=20
    (default)</I> <BR><B>write</B> - <I>clear contents and start saving=20
    data</I><BR><B>append</B> - <I>keep contents, set seek pointer to =
end</I>=20
  </BLOCKQUOTE>
  <P>Note: do not insert or delete rows in a view within which there are =
open=20
  channels, because subsequent reads and writes may end up going to the =
wrong=20
  memo property.=20
  <P></P>
  <DT>EXAMPLES
  <DD>Write a few values (with line separators): <PRE>    mk::view =
layout db.v {b:B}
    mk::view size db.v 1

    set fd [mk::channel db.v!0 b w]
    puts $fd one
    puts $fd two
    puts $fd three
    close $fd</PRE>Read values back, line by line: <PRE>    set fd =
[mk::channel db.v!0 b]
    while {[gets $fd text] &gt;=3D 0} {
        puts $text
    }
    close $fd</PRE>
  <P></P></DD></DL><!--END-->
<P>
<HR SIZE=3D1>
&copy; 2005 Jean-Claude Wippler &lt;<A=20
href=3D"mailto:[e-mail]">[e-mail]</A>&gt; </BODY></HTML>

------=_NextPart_000_001B_01C87A5E.3F217190
Content-Type: image/gif
Content-Transfer-Encoding: base64
Content-Location: http://www.equi4.com/metakit/tcl.gif
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------=_NextPart_000_001B_01C87A5E.3F217190
Content-Type: image/gif
Content-Transfer-Encoding: base64
Content-Location: http://www.equi4.com/metakit/e4s.gif
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------=_NextPart_000_001B_01C87A5E.3F217190--