Release 10.1A: OpenEdge Data Management:
SQL Reference

> ## Overview

> Array fields are created using the Progress 4GL Data Dictionary. OpenEdge SQL provides a mechanism for referencing and updating these arrays. Subscripted references are not supported. OpenEdge SQL manages the arrays as `NVARCHAR` strings, and the string representation is the concatenation of each array element, with a semicolon separating each element.

> To escape an instance of a semicolon in the data of a Progress 4GL `CHARACTER` array, use the escape character tilde before the semicolon ( ~; ). An unquoted question mark represents a `NULL` element. To distinguish a `NULL` element from a question mark, use a tilde as an escape character for a question mark in the data ( ~? ). A tilde is also the escape character for a
> tilde ( ~~ ).

> OpenEdge SQL supplies three built-in functions for extracting an element, and for adding escape characters to and removing escape characters from a single element of a character array. The `PRO_ELEMENT`, `PRO_ARR_ESCAPE`, and `PRO_ARR_DESCAPE` functions provide full internationalization support. A description of each function follows.

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