Table ‘reports’ id docid path val created_at 1 /root/title ‘report A’ CREATE TABLE reports ( id INTEGER PRIMARY KEY, docid INTEGER, path TEXT, val TEXT ); INSERT INTO reports (1, 1, ‘/root/title’, ‘report A’); INSERT INTO reports (2, 1, ‘/root/author’, ‘kaneko’); INSERT INTO reports (3, 1, ‘/root/date’, ‘2009/11/29’); ■ The attribute ‘id’ is the PRIMARY KEY The ‘id’ is key that can be used to identify each row. Table ‘reports’ id docid path val created_at 1 /root/title ‘report A’ 2009-12-11 11:20:36 2 /root/author ‘kaneko’ 3 /root/date ‘2009/11/29’ PRIMARY KEY Fig. Logical Structure of the Table

Table ‘reports’ id docid path val created_at 1 /root/title ‘report A’ 2009-12-11 11:20:36 2 /root/author ‘kaneko’ 3 /root/date ‘2009/11/29’ PRIMARY KEY Logical Structure Keys Associated Records link 1 Record(1, ‘/root/title’, ‘report A’, ‘2009-12-11 11:20:36’) link 2 Record(2, ‘/root/author’, ‘kaneko’, ‘2009-12-11 11:20:36’) link 3 Record(3, ‘/root/date’, ‘2009/11/29’, ‘2009-12-11 11:20:36’) Each key is associated with each record. Physical Structure Fig. Logical Structure and Physical Structure

Record Header Record Data Database Image

Database Header SQLite Database File

SQLite 3 データベースヘッダ に格納されている情報の例 Page size: 04 00 Database encoding: 00 00 00 01 ※ UTF-8: 01 little-endian UTF-16: 02 big-endian UTF-16: 03

Record(1, ‘/root/title’, ‘report A’) Keys Associated Records link 1 Record(1, ‘/root/title’, ‘report A’) link 2 Record(2, ‘/root/author’, ‘kaneko’) link 3 Record(3, ‘/root/date’, ‘2009/11/29’) Each key is associated with each record. Fig. Physical Structure of the Table Record Length (Note that record length is variable) Fig. Database File Layout Example (SQLite 3)