3.1 KiB
The dbtotxt Tool
The dbtotxt utility program reads an SQLite database file and writes its raw binary content to screen as a hex dump for testing and debugging purposes.
The hex-dump output is formatted in such a way as to be easily readable both by humans and by software. The dbtotxt utility has long been a part of the TH3 test suite. The output of dbtotxt can be embedded in TH3 test scripts and used to generate very specific database files, perhaps with deliberately introduced corruption. The cov1/corrupt*.test modules in TH3 make extensive use of dbtotxt.
More recently (2018-12-13) the dbtotxt utility has been added to the SQLite core and the command-line shell (CLI) has been augmented to be able to read dbtotxt output. The CLI dot-command is:
.open --hexdb ?OPTIONAL-FILENAME?
If the OPTIONAL-FILENAME is included, then content is read from that file. If OPTIONAL-FILENAME is omitted, then the text is taken from the input stream, terminated by the "| end" line of the dbtotxt text. This allows small test databases to be embedded directly in scripts. Consider this example:
.open --hexdb
| size 8192 pagesize 4096 filename x9.db
| page 1 offset 0
| 0: 53 51 4c 69 74 65 20 66 6f 72 6d 61 74 20 33 00 SQLite format 3.
| 16: 10 00 01 01 00 40 20 20 00 00 00 04 00 00 00 02 .....@ ........
| 32: 00 00 00 00 00 00 00 00 00 00 00 01 00 00 00 04 ................
| 48: 00 00 00 00 00 00 00 00 00 00 00 01 00 00 00 00 ................
| 80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 04 ................
| 96: 00 2e 30 38 0d 00 00 00 01 0f c0 00 0f c0 00 00 ..08............
| 4032: 3e 01 06 17 11 11 01 69 74 61 62 6c 65 74 31 74 >......itablet1t
| 4048: 31 02 43 52 45 41 54 45 20 54 41 42 4c 45 20 74 1.CREATE TABLE t
| 4064: 31 28 78 2c 79 20 44 45 46 41 55 4c 54 20 78 27 1(x,y DEFAULT x'
| 4080: 66 66 27 2c 7a 20 44 45 46 41 55 4c 54 20 30 29 ff',z DEFAULT 0)
| page 2 offset 4096
| 0: 0d 08 14 00 04 00 10 00 0e 05 0a 0f 04 15 00 10 ................
| 16: 88 02 03 05 90 04 0e 08 00 00 00 00 00 00 00 00 ................
| 1040: 00 00 00 00 ff 87 7c 02 05 8f 78 0e 08 00 00 00 ......|...x.....
| 2064: 00 00 00 ff 0c 0a 01 fb 00 00 00 00 00 00 00 00 ................
| 2560: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 83 ................
| 2576: 78 01 05 87 70 0e 08 00 00 00 00 00 00 00 00 00 x...p...........
| 3072: 00 00 00 00 00 00 00 00 00 ff 00 00 01 fb 00 00 ................
| 3584: 00 00 00 00 00 83 78 00 05 87 70 0e 08 00 00 00 ......x...p.....
| 4080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ff ................
| end x9.db
SELECT rowid FROM t1;
PRAGMA integrity_check;
You can run this script to see that the database file is correctly decoded and loaded. Furthermore, you can make subtle corruptions to the input database simply by editing the hexadecimal description, then rerun the script to verify that SQLite correctly handles the corruption.