RDB/VMS RMU/ALTER DISPLAY — VMS RDB_4.1A
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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Y ─┬────────>───────┬─┬──────────────────────┬─> └─> page-number ─┘ ├─> typebox (*) ─────────────────┤ ├─>
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T ─────────────┤ ├─> display-data ──────┤ ├─>
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R ────────────┤ ├─> display-entry ─────┤ ├─> display-index ─────┤ ├─> display-line ──────┤ ├─>
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E range ───────┤ ├─>
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Additional information available:
STORAGE_AREACHECKSUMCOUNTFREE_SPACEHEADER
LOCKED_FREE_SPACENUMBERTIME_STAMPNEXT_AIPAIP_ENTRIES
page-numberasteriskdisplay-datadisplay-entrydisplay-indexdisplay-lineSPACE range
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.
display-data
display-data = ──>
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A ─┬─┬─────────>───────┬─┬───────>──────┬─┬─> offset ──> │ ├─> typebox (/)
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L ─────┤ ├─> typebox (/)
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E ─────┤ │ │ └─> typebox (/)
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L ─┘ ├─> typebox (/)
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D ─┤ │ │ └─> typebox (/)
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D ─────┘ │ └─> typebox (/)
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I ──┬──────>─────┬────────────┘ └─> typebox (:) ──> n ─┘
Additional information available:
DATA offset
Displays the number of bytes specified. If you do not specify the /HEXADECIMAL or /DECIMAL parameter, 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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Y ─┬───>──┬─┬─────────>────────┬──> ├─> n ─┤ ├─> typebox (*) ─────────────┤ └─> typebox (*) ─┘ ├─>
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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 between 0 and the number of AIP_ENTRIES. 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 area inventory page (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 last TSN to enable snapshots for a logical area. The TSN value is contained in a longword.
RECORD_LENGTH
Displays the value for the length in bytes of the record size. The RECORD_LENGTH 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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N
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X ─┬───>──┬─┬─────>─────┬──> ├─> n ─┤ ├─> typebox (*) ──────┤ └─> typebox (*) ─┘ ├─>
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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 range
Displays 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 optional 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. When you specify a range, you reduce the output display. The specified range of SPAM entries is included in the display; other SPAM entries outside your specified range may also be included in the display. 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.
NEXT_AIP
Displays the page number of the next area inventory page.
AIP_ENTRIES
Displays a value for the number of AIP entries on the current area inventory page.
Examples
Example 1
This example displays page 94.
RdbALTER> DISPLAY 94
0001 0000005E 0000 page 94, physical area 1
7B429FB0 0006 checksum= 7B429FB0
0093249F 9EBDB820 000A time stamp= 14-FEB-1990 10:42:35.81
0000 0004 0012 4 free bytes, 0 locked
FFFFFFFF 0016 next area bit map page -1
00000000 001A max set bit index 0
00000000 001E MBZ '....'
00001E60 0022 bitvector count 7776
00000000000000000000000000000000 0026 bitvector '................'
:::: (59 duplicate lines)
000000000000000000000000 03E6 bitvector '............'
00000000 03F2 MBZ '....'
801F 03F6 bitmap page for logical area 31
0000000000000000 03F8 MBZ '........'
Example 2
This example displays the number of the current storage area.
RdbALTER> DISPLAY STORAGE_AREA
0001 0000 area 1
Example 3
This example displays the number of area inventory page entries
on Area 1, Page 2 of the MF_PERSONNEL database, and the value of
the highest snapshot enabled TSN of area inventory page entry
14. This example also displays the number of the next area
inventory page in the current storage area.
RdbALTER> AREA 1 PAGE 2
RdbALTER> DISPLAY AIP_ENTRIES
0010 0022 16 logical area entries
RdbALTER> DISPLAY ENTRY 14 TSN
entry #14
00000001 0386 snaps enabled TSN 1
RdbALTER> DISPLAY NEXT_AIP
00000003 0016 next area inventory page 3