Using Caché Multi-Dimensional Storage - InterSystems ...

If you are using Caché ObjectScript, you can construct global references at runtime using
indirection.
3.1.3 Storing Structured Data in Global Nodes
Each global node can contain a single string of up to 32K characters.
Data is typically stored within nodes in one of the following ways:
• As a single string of up to 32K characters (specifically, 32K minus 1).
• As a character-delimited string containing multiple pieces of data.
To store a set of fields within a node using a character delimiter, simply concatenate the
values together using the concatenate operator (_). The following Caché ObjectScript
examples use the # character as a delimiter:
SET ^Data(id)=field(1)_"#"_field(2)_"#"_field(3)
When the data is retrieved, you can pull the fields apart using the $PIECE function:
SET data = $GET(^Data(id))
FOR i=1:1:3 {
SET field(i) = $PIECE(data,"#",i)
}
QUIT
• As a $LIST-encoded string containing multiple pieces of data.
The $LIST functions use a special length-encoding scheme that does not require you to
reserve a delimiter character. (This is the default structure used by Caché Objects and
SQL.)
To store a set of fields within a node use the $LISTBUILD function to construct a list:
SET ^Data(id)=$LISTBUILD(field(1),field(2),field(3))
When the data is retrieved, you can pull the fields apart using the $LIST or $LISTGET
functions:
SET data = $GET(^Data(id))
FOR i = 1:1:3 {
SET field(i)=$LIST(data,i)
}
QUIT
• As one part of a larger set of data (such as a stream or “BLOB” ).
Storing Data in Globals
As individual nodes are limited to just under 32K of data, larger structures, such as
streams, are implemented by storing data in a set of successive nodes:
Using Caché Multi-Dimensional Storage 17