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Maximum Length Property

Description

This property can potentially limit the amount of data that an item is allowed to contain internally (in the Forms server) when it's in native format. It can also potentially limit the number of character (or bytes) displayed or entered by the end user. That is, it can specify a data limit and/or a user interface (UI) limit. The exact effect depends upon several factors, including the item's Data type, Data Length Semantics, and Format Mask properties.

For a character item (datatypes CHAR, ALPHA, LONG), the Maximum Length property specifies a data limit. The property value specifies either the maximum number of bytes or else the maximum number of characters, depending upon the value of the Data Length Semantics property. Within a group of character mirror items, the Maximum Length property is always taken from the master mirror item. A compiler (generator) warning is issued if a non-zero non-default value is specified in a subordinate mirror item.

If a character item has no format mask (the Format Mask property is null), then the Maximum Length property (taken from the master mirror item) also specifies a UI limit. When the Forms server is using the UTF8 character set , this UI limit has the same semantics (byte versus character) as the data limit. When the Forms server is using a multi-byte character set other than UTF8, and the Data Length Semantics property specifies byte semantics, Forms cannot prevent the end user from typing in too many bytes. Instead, it uses character semantics for the UI limit.

In such a case, the end user is allowed to type in too many bytes. When the end user attempts to navigate out of the current validation unit, one of two things will happen. If the application property FLAG_USER_VALUE_TOO_LONG is set, an error will be flagged and the excess characters on the right will be selected. If this application property is not set, the excess characters will be quietly truncated, and the navigation will succeed.

If a character item has a format mask, then the item's UI limit is derived from the format mask. This limit is always a character limit.

For a number item (datatypes NUMBER, INT, MONEY, RNUMBER, RINT, RMONEY), the Maximum Length property specifies a user interface limit. This limit is always a character limit. There is no data limit. The data item can always internally hold up to 23 bytes (which is the maximum size of an Oracle number in native format), regardless of the value of the Maximum Length property.

For a date or time item (datatypes DATETIME, DATE, TIME, JDATE, EDATE), the Maximum Length property specified in Forms Builder has almost no effect (See the Query Length property for a discussion of the only effect). As with "number" items, there is no data limit. For DATE and DATETIME items, the internal value is 7 bytes long, and for TIME, JDATE and EDATE items, the internal value is 4 bytes long . The user interface limit is derived from the format mask. This limit is always a character limit which is what is returned by GET_ITEM_PROPERTY(item, MAX_LENGTH).

Applies to: all items except buttons, image items, and chart items.

Set At Runtime: No

Get At Runtime: Yes, as MAX_LENGTH.

Required: No

Values

A number from 0 to 65534

Default

30

Usage Notes


Query Length Property