Computing & AI Class 10
Data Handling II: Databases & Structured Data
Build a table in code: find a key, filter, sort, and count.
11 lessons · ~82 min total
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Lessons in this topic
- 0 Start here A roadmap: one row per record, a key, a header that names a position, one and two conditions, order, and a count. · 5 min You are here
- 1 One record, one row A record is one row of values. One field takes two positions: row, then column. · 8 min
- 2 The naming value A key is a column whose values each name one record. A shared value cannot name either. · 8 min
- 3 Naming the columns The headers list turns a column name into a position. Minus one means no such column; do not use it as a position. · 8 min
- 4 Asking the register one question A query walks the rows and keeps the ones where one named field meets the condition — including nothing. · 8 min
- 5 Two conditions, both true Two conditions joined by and keep a row only when both hold — fewer rows or the same, never more. · 8 min
- 6 The answer, in order The same selection passes you already wrote, read through the position of the key, moving whole rows. · 9 min
- 7 Counting the groups in the answer Count the answer, not the table. This report lists its groups first, so an empty group still shows a 0. · 8 min
- 8 What a database adds A database program can give the same answer as your walk, over far bigger tables. · 7 min
- 9 The big picture Eight ideas, one table: a key, a header position, one and two conditions, order, and a count that came from real runs. · 5 min
- 10 Track quiz Cheat-sheet table plus a reveal quiz — one line per idea, and extra questions on the traps that catch nearly everybody. · 8 min
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