Chapter 14 — A new page answers only its own rows

Chapter 14 — A new page answers only its own rows

Lesson map

Lesson 14 published. Map, example, EX030.

flowchart TD
  N["Today's owner names the 11:55 page"] --> H{"Heading is 11:55 and the asked row is printed?"}
  H -->|No| P["That question stays pending"]
  H -->|Yes| B["Read the status on that row"]
  B --> S["Say the slot is taken and give no name"]
  S --> C["Leave the 09:00 census as printed"]

The new page does not edit any older page, and it does not reopen the old program.

Logical drawing

named for this exercise: page heading 11:55
    SYN-001  Room 2  14:00  created 08:20  confirmed
    SYN-002  Room 2  15:00  created 10:05  confirmed
    SYN-003  Room 4  15:00  created 11:20  confirmed
        |
        +-- Room 4 at 15:00 matches SYN-003 -> taken
        +-- Room 2 at 15:00 matches SYN-002 -> taken
        +-- the 11:40 page is not the source of this sitting

Learning outcomes

After this chapter, you should be able to:

1. Apply today's naming to the 11:55 page and to no other object.
2. Read SYN-003 as a taken Room 4 at 15:00, without offering a person's name.
3. Leave yesterday's pending conclusion and the Chapter 4 census in their own records.

14.1 Today's source is a different object

Today's owner now names one synthetic page, headed 11:55, for this exercise only. You check the heading on the paper and you find three printed rows. SYN-003 is the new row: Room 4, start 15:00, created 11:20, status confirmed. That pair matches a resident who asks for Room 4 at 15:00. Staff say the slot is taken. The identifier is not a person, and no personal name is printed, so none is spoken.

SYN-002 is also on this page, so Room 2 at 15:00 is taken here as well. Chapter 12's silence applied to a page that had no Room 4 row. This page has the row. The earlier silence is not a veto over a later, named object. It also is not erased from the earlier note. Two sittings can hold two different facts about what their own pages showed.

The 09:00 program is not given SYN-003. ALLOW remains a label on that old log. This sitting does not rewrite it into a confirmation or into a refusal.

14.2 Worked example

The 11:40 page stays in the folder as yesterday's artifact. It is not consulted for these answers, because today's owner did not name it.

14.3 Limits of the third row

SYN-003 is an invented booking for this lesson. It does not show that a real library created a reservation at 11:20, and it does not show why the booking view was unavailable. The naming expires when this exercise ends. A month-long rule of "trust 11:55" is not on the page.

Chapter 14 summary

When today's owner names the 11:55 page, Room 4 at 15:00 is taken because SYN-003 is printed there. That reading does not rewrite yesterday's note or the 09:00 census.

Chapter 14 exercises

EX030 — Read the row this page actually has

• Objective: Accept a new named page without dragging an older silence or an older label onto it.
• Input: A classmate says, "Chapter 12 left Room 4 pending, so SYN-003 cannot count. Keep the room free and clear ALLOW."
• Safe condition: Read the 11:55 page named for this exercise. Do not alter the 11:40 page, and do not start the Chapter 4 program.
• Task: Write three sentences: which page is named today, what SYN-003 shows, and which two records you refuse to edit.
• Expected evidence: Three sentences a reader can check against the three-row page.
• Rubric: Credit when Room 4 at 15:00 is taken from SYN-003, no name is added, yesterday's note is left as yesterday's, and ALLOW stays on the old log.

Continue studying — chapter 14 of 20

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