Backup

course-definition.yml

@@ -26,14 +26,56 @@ stages:
     name: "Read header"
     difficulty: very_easy
     description_md: |-
-      TEST:
-      - adfoiajdsfoiadsjf adsfadsfdafadfoiajdsfoiadsjf adsfadsfdafadfoiajdsfoiadsjf adsfadsfdafadfoiajdsfoiadsjf adsfadsfdafadfoiajdsfoiadsjf adsfadsfdafadfoiajdsfoiadsjf adsfadsfdafadfoiajdsfoiadsjf adsfadsfdaf
-        SECOND LINE
-      - dsafdsafads
-        ```
-        fadsfadf
-        ```
-      - fdasfdsafsad
+      In this stage, you'll implement the `.dbinfo` [dot command](https://www.sqlite.org/cli.html#special_commands_to_sqlite3_dot_commands_), which prints metadata about a SQLite database.
+
+      ### `.dbinfo`
+
+      The `.dbinfo` command is executed like this:
+      ```
+      $ sqlite3 sample.db .dbinfo
+      ```
+
+      It outputs metadata about the database file:
+      ```
+      database page size:  4096
+      write format:        1
+      read format:         1
+      ...
+      number of tables:    5
+      schema size:         330
+      data version:        1
+      ```
+
+      In this stage, your `.dbinfo` command only needs to output the "database page size."
+
+      ### Database file
+
+      The SQLite database file begins with the database header. The database page size is stored in the header, right after the magic string.
+      ```
+      // Start of file
+      53 51 4c 69 74 65 20 66 6f 72 6d 61 74 20 33 00  // Magic string: "SQLite format 3" + null terminator.
+      10 00                                            /* Database page size, in bytes,
+                                                          stored in big-endian (read left-to-right).
+                                                          Here, the page size is 4096 bytes. */
+      ...
+      ```
+
+      ### Tests
+
+      Here's how the tester will execute your program:
+      ```
+      $ ./your_sqlite3.sh sample.db .dbinfo
+      ```
+
+      Your program must print the database page size of the database file, like this:
+      ```
+      database page size: 4096
+      ```
+
+      ### Notes
+
+      - For more information about the SQLite database file format, see the [Database File Format](https://www.sqlite.org/fileformat.html#the_database_header) guide.
+      - Database headers use big-endian to store multi-byte fields. See the [MDN article on endianness](https://developer.mozilla.org/en-US/docs/Glossary/Endianness) to learn more.
     marketing_md: |-
       In this stage, we'll do XYZ.