RDB/VMS RMU/ALTER DISPLAY — VMS RDB_4.0
Requests display of data fields from a database page. An individual DISPLAY command can include only one of the display options.
Additional information available:
Format
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Additional information available:
STORAGE_AREACHECKSUMCOUNTFREE_SPACEHEADER
LOCKED_FREE_SPACENUMBERSPACETIME_STAMP
page-numberasteriskDATA offsetdisplay-entrydisplay-indexdisplay-line
page-number
Identifies the page whose information you want to display. The current page is the default.
asterisk
The asterisk (*) parameter displays the entire page.
STORAGE_AREA
Displays the 2-byte storage area identification.
CHECKSUM
Displays the 4-byte page checksum field.
COUNT
Displays the 2-byte field showing the number of line index entries. If this number is 1, the page contains only the SYSTEM record.
DATA offset
Displays 1, 2, or 4-bytes of data in the radix specified. If you do not specify radix, the default radix is assumed. See the description of the RADIX command in this help file for information on how to set a default radix. The value you specify for "n" is the number of bytes you want to display. The maximum value that can be specified for "n" is the size of the page minus the offset. The /BYTE, /LONGWORD, and /WORD qualifiers cannot be used with the /ASCII qualifier.
FREE_SPACE
Displays the 2-byte field indicating how much free space remains on the page.
HEADER
Displays the entire page header.
display-entry
display-entry = ──>
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Additional information available:
ABMLOGICAL_AREAPHYSICAL_AREAALENGTHANAME
TSNRECORD_LENGTHINUSE
ENTRY n asterisk
Refers to an area inventory page (AIP) entry on the database page. If you specify a value for n, it must be a number from 0 to 15. If you specify the asterisk (*) parameter, the information you request with the other DISPLAY ENTRY parameters is displayed for each AIP entry on the database page.
asterisk
Displays the same information that is displayed when you specify the ABM, LOGICAL_AREA, PHYSICAL_AREA, ALENGTH, ANAME, TSN, RECORD_LENGTH, and INUSE parameters.
ABM
Displays the first area bitmap page for the specified AIP entry. The value is contained in a longword.
LOGICAL_AREA
Displays the number of the logical area. The value is contained in a word.
PHYSICAL_AREA
Displays the number of the physical area. The value is contained in a word.
ALENGTH
Displays the length of the name of the logical area. The value is contained in a byte. The name of the logical area can be from 1 to 31 bytes in length.
ANAME
Displays the name of the logical area. The value is contained in a 31 character text field.
TSN
Displays the value of the highest snapshot enabled transaction sequence number (TSN). The value is contained in a longword.
RECORD_LENGTH
Displays the length in bytes of the record. The value is contained in a word.
INUSE
Displays the entry's in use flag. The value is contained in a byte.
display-index
display-index = ──>
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Additional information available:
INDEX n
Displays the offset field, the length field, or both from the line index indicated by n. The integer denoting INDEX is zero based. For example, if you enter DISPLAY INDEX 3 OFFSET, the offset address field from the fourth line index is displayed. If you enter DISPLAY INDEX 4 length, the length field from the fifth line index is displayed. If you enter either DISPLAY INDEX 2 or DISPLAY INDEX 2 *, both the offset and the length fields from the third line index are displayed. The integer n is optional. The present value of the relevant pointer is the default. References to INDEX are invalid if the current page is a SPAM page.
display-line
display-line = ──>
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E ─┬───>──┬─┬────────>───────┬──> ├─> n ─┤ ├─> typebox (*) ───────────┤ └─> typebox (*) ─┘ └─>
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Additional information available:
LINE
Displays information from an individual storage segment. You can display the record-type field or the entire content of the storage segment line indicated by n. The integer denoting LINE is zero based. For example, LINE 0 refers to the first line, and LINE 3 refers to the fourth line. The integer n is optional. The present value of the relevant pointer is the default. References to LINE are invalid if the current page is a SPAM page.
LOCKED_FREE_SPACE
Displays the 2-byte field indicating how much free space is allocated for exclusive use by a run unit.
NUMBER
Shows the 4-byte page number field.
SPACE
Displays a specified range of SPAM entries; it is valid only if the current page is a SPAM page. SPACE is the only option that you can use in DISPLAY and DEPOSIT commands that access a SPAM page. range = ┬─> typebox (*) ─────────────────────────>────────────────────────────────┬─> └─> lower-data-page-number ─┬────────────────>─────────────────┬┘ └─> typebox (:) ──> higher-data-page-number ─┘ The range value can be an asterisk (*), referring to all entries, or a set of consecutive entries that you describe as shown in the preceding syntax diagram. Each entry on a SPAM page consists of 2 bits, containing a value 0 through 3 that represents a fullness threshold. For example, if the nth SPAM entry contains a 2, it means that the nth data page in the interval has reached a percentage of fullness greater than the second threshold for the area, but less than or equal to the third threshold.
TIME_STAMP
Displays the 8-byte time and date stamp field.
Examples
Example 1 This example displays page 94. RdbALTER> DISPLAY 94