Using Caché Objects - InterSystems Documentation

Data Types
SQLCATEGORY Values
Value
CURRENCY
DATE
DOUBLE
INTEGER
NAME
NUMERIC
STRING
TIME
TIMESTAMP
Caché Data Type
%Currency
%Date
%Float
%Integer, %Boolean
%Name
%Numeric
%String, %Binary, %List
%Time
%TimeStamp
11.2.4 Data Formats and Translation Methods
When handling data, Caché uses a number of different formats, depending on the situation.
These have various purposes — such as for displaying data in a human-readable format or
for manipulating data programmatically. Caché data types automatically convert data among
these formats. If you create your own data type that is a subclass of a Caché data type, any
property using your data type automatically includes the methods for converting among the
various formats.
You only need to know about these formats and conversions between them if you are either
creating a data type not based on a system data type or performing non-standard data
manipulation.
The formats are:
• Display — The format in which data can be input and displayed. For instance, a date in
the form of “April 3, 1998” or “23 November, 1977.”
• Logical — The in-memory format of data, which is the format upon which operations
are performed. While dates have the display format described above, their logical format
is as an integer; for the sample dates above, their values in logical format are 57436 and
50000, respectively.
• Storage — The on-disk format of data — the format in which data is stored to the database.
Typically this is identical to the Logical format.
96 Using Caché Objects