mtree: refreshed the readme

modules/mtree/README

@@ -14,8 +14,6 @@ Juha Heinanen
 
    tutpro.com
 
-Edited by
-
 Juha Heinanen
 
    <[email protected]>
@@ -198,11 +196,29 @@ modparam("mtree", "db_table", "mymtrees")
 
 3.3. mtree (string)
 
-   Definition of memory tree with parameters name, dbtable, type, and
-   multi. Name is name of the tree, dbtable is name of dbtable where tree
-   is stored, type is type of tree elements (0 = string, 2 = integer), and
-   multi tells if dbtable can contain more than one tree (0 = one tree, 1
-   = more than one tree identified by tname column).
+   Definition of memory tree with using a prameters format string. The
+   parameter names can be:
+     * name - the name of the tree to be used for referencing inside
+       configuration file.
+     * dbtable - the name of the database table from where to load the
+       records stored in the tree.
+     * cols - the column names of the database table. They must be
+       enclosed in quotes in order to form a valid SIP parameter value and
+       be separated by comma. The first column corresponds to tprefix.
+       When specified, there must be at least two columns. If this
+       attribute is not specified, then the global module parameters for
+       tprefix and tvalue are used. If more than one value columns are
+       specified, the tree will pack the column values in a comma
+       separated string, which will be associated with the prefix (string
+       transformation {s.select,...) can be used in configuration file to
+       extract a specific column value).
+     * type - the type of tree elements (0 = string, 2 = integer). It is
+       valid only when the (tprefix, tvalue) pairs are loaded (not for
+       muti-column values).
+     * multi - tells if dbtable can contain more than one tree (0 = one
+       tree, 1 = more than one tree identified by tname column). It is
+       valid only when the (tprefix, tvalue) pairs are loaded (not for
+       muti-column values).
 
    This parameter can be set many times to add more trees in memory.
 
@@ -212,6 +228,8 @@ modparam("mtree", "db_table", "mymtrees")
 ...
 modparam("mtree", "mtree", "name=mytree1;dbtable=routes1;type=0")
 modparam("mtree", "mtree", "name=mytree2;dbtable=routes2;type=0;multi=1")
+modparam("mtree", "mtree",
+    "name=mytree1;dbtable=routes1;cols='key1,val1,val2,val3'")
 ...
 
 3.4. tname_column (string)