Edit data base location

The Data Base Location screen, shown in the following figure, is used to control the editing of your database. This screen is initially displayed after you specify a DBD from the Primary Option Menu or the DBD Member List screen. Hierarchical Structure of Sample Database graphically displays the hierarchical structure of a sample database.

Data Base Location Screen

Line Cmd

Used to select a segment for editing. For more information, see Selecting a Segment.

Level

Displays the segment type’s hierarchical level number in the database. For the root segment type, the primary DBD name is displayed next to the level number.

Seg

Displays the segment name as specified in the DBD.

Description

Displays a 15-character segment description. This description is retrieved from the segment/layout cross reference created in Option 7 of File-AID for IMS/ISPF.

Key LTH

Displays the segment key length. If the segment is nonkeyed, zero is displayed.

Key Value

Displays up to 30 positions of the key value for each segment occurrence. Additional information about this field is provided in the next section.

Hierarchical Structure of Sample Database

Selecting a Segment

When you initially enter the Data Base Location screen, your current position in the database is dependent on the type of database being edited.

For a database defined without a randomizing routine, the first root segment occurrence is retrieved and the key is placed in the Key Value column on the root segment line (see the following figure). File-AID for IMS considers this root segment occurrence to be your current position in the database.

For HDAM and DEDB databases, File-AID for IMS allows you to specify a key value to retrieve the first segment in the database. This process reduces IMS’ search time to retrieve a root segment for a database defined with a randomizing routine.

Data Base Location Screen - Selecting a New Segment

The Data Base Location screen indicates your current position by placing an asterisk in the Line Cmd field of all segment types in the hierarchical path to your current position. The first 30 positions of the key value for each segment occurrence in the hierarchical path to your current position are also shown.

To change your current segment position, enter the key value for each segment type in the hierarchical path to the segment occurrence you want. Then, enter one of the six valid line commands shown at the bottom of the screen in the Line Cmd field next to the segment type you want.

File-AID for IMS retrieves the new segment occurrence and then, based on the line command specified, does one of the following:

S	Enters the Formatted editing mode.
SU	Enters the Unformatted editing mode.
SI	Enters the Index editing mode.
K	Displays the Key Specification screen and enters the Formatted editing mode.
KU	Displays the Key Specification screen and enters the Unformatted editing mode.
KI	Displays the Key Specification screen and enters the Index editing mode.

To retrieve the first segment in an HDAM and DEDB database, you must enter one of the line commands and, optionally, a key value on the Data Base Location or Key Specification screen. File-AID for IMS retrieves the first root segment if a key value is not specified on the Data Base Location screen with line command S, SU, or SI.

Use the K, KU, or KI line command when you need greater flexibility to specify key values than the Data Base Location screen allows. By using one of these line commands to proceed to the Key Specification screen before entering an editing mode, you can, for example, enter key values greater than 30 characters in length.

To specify the key values in the hierarchical path to a segment occurrence, you can leave any or all of the Key Value fields blank. If you leave the Key Value field blank on the segment type you selected, File-AID for IMS formats an unqualified SSA at that level. IMS then retrieves the first occurrence of that segment type in the specified hierarchical path.

If you enter a key for the segment type you selected but leave the Key Value field blank for one of its parent segment types, File-AID for IMS formats an unqualified SSA at the parent’s level. IMS then searches through each occurrence of that parent segment type in the specified hierarchical path. The search stops when an occurrence of the segment type you selected is found with a key value that matches what was entered or when all occurrences of the parent without a key entered are searched.

For example, in the following figure, File-AID for IMS formats the SSAs so that IMS searches through all occurrences of the ORDR020 segment type that exist under the ORDR010 root with a key equal to AA2222, looking for an occurrence of the ORDR030 segment type with a key of 02.

If the correct ORDR030 segment occurrence is found, you enter the Unformatted editing mode with that ORDR030 segment as your current segment. If the correct ORDR030 segment cannot be found, an error message is displayed on the Data Base Location screen.

If, as shown in the example, both the ORDR010 and ORDR020 Key Value fields are blank when the ORDR030 segment type is selected, File-AID for IMS formats the SSAs so that IMS searches for the first ORDR030 occurrence in the database with a key value of 02. If all three Key Value fields are blank, IMS retrieves the first ORDR030 occurrence in the database.

Data Base Location Screen - Leaving a Key Field Blank

When a segment type is nonkeyed, File-AID for IMS formats an unqualified SSA at that level, which results in the same processing done for segment types where you did not enter key values.

When key values of 13 positions or less in length are specified, you can enter the hexadecimal representation of the key value. The format is X’nnnn...’, where each n digit is one half-byte of data. You must enter an even number of digits when using this format.

When a key value in character or hexadecimal format is specified and the value entered is shorter than the length shown in the Key LTH column, File-AID for IMS blank pads the key value to the right.

The Data Base Location screen always shows the hierarchical path to the segment occurrence in the database that is the current position with asterisks and key values. The Data Base Location screen saves those key values and displays them each time you return to the screen. Saved key values are updated for each segment in the current hierarchical path each time you return to the Data Base Location screen.

Key values that are not in the current hierarchical path are not updated. Saved key values can be updated by typing over them, whether or not they are in the current hierarchical path.

For example, in the following figure, the hierarchical path to the current segment position includes segment types ORDR010 and ORDR040 with key values of AA2222 and 01C7477A, respectively. Those two key values are displayed each time you return to the Data Base Location screen until different occurrences of the ORDR010 and ORDR040 segment types are part of the current hierarchical path or until you change the key values.

Data Base Location Screen - Saved Key Values

The last time this screen was displayed, ORDR020 and ORDR030 were in the current hierarchical path with key values 01 and 03. The last time that ORDR050 was in the current hierarchical path, it did not show the key value of 01. This value was typed in manually.

The Data Base Location screen saves prior key values to enable you to easily reposition to previously selected segment occurrences.

Terminating the Screen

Do one of the following to terminate the Data Base Location screen:

• Enter RETURN or DBD to return to the DBD Member List screen.
• Enter END to return to the Primary Option Menu or the DBD Member List screen.
• Enter MENU to return to the Primary Option Menu.