RPG Data Types

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In programming, data type is an important concept.

Variables can store data of different types, and different types can do different things.

RPG has the following data types built-in by default, in these categories:

Text:	char, varchar
Numeric:	int, packed, zoned, uns
Date and Time:	date, time, timestamp
Binary:	bin
Boolean	ind
Pointer	pointer
SQL Types:	clob, blob

The different types

Data Type	Description	Example
char	Character. A string with a defined length.	dcl-s FirstName char(128);
varchar	Variable Character. A string with a variable length with the max length defined. Note that the field internally has two bytes that hold the actual used length of the field.	dcl-s FirstName varchar(128);
int	Integer. A numerical integer field that stores binary and that has got a set of predefined types with limits of how big numbers it can hold. Also stores the sign of the number, i.e if it’s positive or negative.	// Value -128 to 127 (1 byte) dcl-s Integer3 int(3) // Value -32,768 to 32,767 (2 bytes) dcl-s Integer5 int(5) // Value -2,147,483,648 to 2,147,483,647 (4 bytes) dcl-s Integer10 int(10); // Value -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807 (8 bytes) dcl-s Integer20 int(20);
packed	Packed. A numeric datatype that can hold decimal numbers. Stores two digits per byte and the max size needs to be odd in order to hold the positive/negative sign.	// A Packed Field with a maximum of 7 numbers, where two are decimal positions. Max value is 99999.99. Occupies only 4 bytes dcl-s packedField packed(7:2); // A packed field without decimals. Max value is 9999999 dcl-s packedField packed(7:0);
zoned	Zoned. A numeric datatype that can hold decimal numbers. Stores one digit per byte and needs to be defined with a maximum number of digits to hold.	// A zoned field with a maximum of 7 numbers, where two are decimal positions. Max value is 99999.99. Occupies only 7 bytes dcl-s zonedField (7:2) // A packed field without decimals. Max value is 9999999 dcl-s packedField packed(7:0);
uns	Unsigned. A numerical integer field that stores binary and that has got a set of predefined types with limits of how big numbers it can hold. Does NOT store the sign of the number, i.e if it’s positive or negative. Only positive numbers are allowed.	// Value 0 to 255 (1 byte) dcl-s unsignedInteger3 int(3) // Value 0 to 65,535 (2 bytes) dcl-s unsignedInteger5 int(5) // Value 0 to 4,294,967,295 (4 bytes) dcl-s unsignedInteger10 int(10); // Value 0 to 18,446,744,073,709,551,615 (8 bytes) dcl-s unsignedInteger20 int(20);
date	Date. A datatype that contains proper dates. Like a built in calendar. Stores only the date with the default format being *ISO (YYYY-MM-DD). There are many different formats with different separators to choose from. Can not store invalid dates like 2020-07-45…	// A date field. Will use the default format dcl-s aDate date; // A date field given a 2digit year format. dcl-s twoDigitYearDate date(*ymd);
time	Time. A datatype that stores time in a proper format. Can be used to perform time calculations. There are many different formats with different separators but the default being *ISO (hh.mm.ss)	// A time field. Will use the default format dcl-s aTimeVariable time; // A time field with different separator dcl-s timeSeparator time(*hms,);
timestamp	Timestamp. A complete date and time combined down to 12 fractions of a second. Kind of like a stamp in time, an exact moment in time. The milliseconds are optional but defaults to a precision of 6 digits. (YYYY-MM-DD-hh:mm:ss.ffffff)	// A default timestamp (YYYY-MM-DD-hh:mm:ss.ffffff) dcl-s defaultTimestamp timestamp; // A timestamp without fractional seconds (YYYY-MM-DD-hh:mm:ss) dcl-s zeroTimestamp timestamp(0); // A timestamp with maximum fractional seconds (YYYY-MM-DD-hh:mm:ss.ffffffffffff) dcl-s maxTimestamp timestamp(12);
bin	Binary. A binary data type called binary decimal. It’s binary like int and uns but is NOT recommended to use any more thus it has built in limitations. It has a heritage in how the implementation was done back in the days. Exists mainly for compatibility reasons.	// A binary decimal variable dcl-s binaryField bindec(5);
ind	Indicator. RPG’s equivalent of a boolean. It can only hold the values ‘0’ and ‘1’, indicating if something has occurred or not.It’s either on or off. True or false.	// An indicator with its default value (off = ‘0’) dcl-s myIndicator ind; // An indicator initilized to be on = ‘1’ dcl-s myIndicator ind inz(*on);
pointer	Pointer. Basing pointers are used to locate the storage for based variables. It’s like pointing to a place in memory, able to pass that reference around. A little bit more hardcore programming.	dcl-s aPointer pointer;
clob	Character Large Object. It’s a data type that can store large amounts of character data, around 2 GB. Used for large text documents.	// A CLOB. Needs to be defined with a max size dcl-s aCLOB sqltype(CLOB:500)
blob	Binary Large Object. It’s a data type that can store binary data but differs from other binary data types, like int, in that it is typically used to store images, audio files, videos etc.	// A BLOB. Needs to be defined with a max size dcl-s aBLOB sqltype(BLOB:10000)