Key specification within Browse/Edit

The following figure is used to specify the fully concatenated key of a segment occurrence that you want to retrieve or create. This screen can be invoked from other screens within the browse/edit conversation as follows:

• From the Data Base Location screen with the K, KU, or KC line command or the INSERT primary command (See Edit Database Location and Inserting a Segment).
• From the Formatted screen, with the KEY, INSERT, or REPEAT primary command.
• From the Unformatted screen with the KEY, INSERT, or REPEAT primary command.
• From the Character screen, with the KEY primary command or the I, K, R, and RA line commands (See KEY and Edit Character Line Commands).

Examples of how each of these four screens interact with the Key Specification screen are shown later in this section.

Key Specification Screen

Segment to Retrieve

Displays the target segment that you want to retrieve, insert, or repeat. The last segment type shown in the screen body is referred to as the target segment type. If you entered the Key Specification screen with a primary command (KEY, INSERT, REPEAT), the target segment type is the same as the current segment type. However, if you entered the Key Specification screen with a line command (K, KU, KC, I, R, RA), the target segment type is the same as that of the segment on the line where you entered the command.

Level Number/Data-name

The first line in the first column of each section starts with the literal LVL and the hierarchical level number within the primary database of the segment type corresponding to that section. Next to the level number is the segment name.

The remaining lines in the first column of each section display the segment layout level numbers and data-names that define the key fields for that section’s segment type. Where possible, File-AID for IMS shows the level numbers and data-names from the segment layout that defines the segment type. If a valid segment layout cannot be found or determined, File-AID for IMS generates a generic key field name in the format * segment-name KEY *, where segment-name is the name of the segment type for that section. File-AID for IMS also assigns a level number of 01 to generated key field names. The screen in Key Specification Screen shows an example of key field name generation.

Format

The Format column serves the same purpose on the Key Specification screen as on the Formatted screen - Character mode¹.

RO

When retrieving, inserting, or repeating the target segment, File-AID for IMS formats the SSA used in the DL/I call with the relational operator specified for each segment type. Following are the valid relational operators:

The first six relational operators are identical to those you can use when coding an SSA in an IMS application program. File-AID for IMSuses the specified relational operator when issuing its DL/I calls. The UQ relational operator is unique to File-AID for IMS. When you specify UQ for a segment type, File-AID for IMS formats an unqualified SSA for that segment type.

When you enter the Key Specification screen, File-AID for IMS pre-formats the Relational Operator column for each segment type with an = or UQ as follows:

Field Value

When you enter the Key Specification screen, the key field lines for each segment type in the current hierarchical path are pre-formatted with their current values. The key fields for segment types in the hierarchical path to the target segment but not in the current hierarchical path are pre-formatted with blanks (HEX 40s).

Each key field value line allows up to 30 characters to be entered. The valid syntax for key values is the same as described for field values on here. File-AID for IMS validates the length of the key value entered against the key length shown in the Format column for that line. If the value entered is shorter than the Format column’s key length, the value is padded with blanks (HEX 40s). If the value entered is longer, an error is returned.

Key field values display in either three-line vertical HEX or Character mode (Key Specification Screen). You can switch from one mode to another using the HEX ON/OFF command.

The top line of the HEX display (Key Specification Screen - Hex Key Field Values), represents the character format of the key field value, the middle line represents the upper half byte of each character in HEX, and the third line represents the lower half-byte of each character in HEX. To change key value contents, you can type over the character or HEX line. If you type over both the character and HEX lines for the same character, the character type over is ignored.

Key Specification Screen - Hex Key Field Values

File-AID for IMS deviates from its normal relational operator and key field pre-formatting in the following situations:

• When the INSERT primary command is used to insert a target segment type that is not in the current hierarchical path, the relational operator is set to EQ and the KEY VALUE field to blanks.
• Non-keyed segment types always have UQ as the relational operator and the literal *** NON-KEYED SEGMENT *** in the Key Value Field column.
• When you enter the Key Specification screen from the Data Base Location screen with a K, KU, or KC line command, the Relational Operator field is set to EQ for all segment types displayed. The key values shown for each segment type are taken directly from the Key Value column on the Data Base Location screen. For more information, see Selecting a Segment on how File-AID for IMS maintains key values on the Data Base Location screen.

This section provides information about the following topics: