List of tables, db schema, dump etc using the Pyth

Question

For some reason I can't find a way to get the equivalents of sqlite's interactive shell commands:

.tables
.dump

using the Python sqlite3 API.

Is there anything like that?

Answer 1

You can fetch the list of tables and schemata by querying the SQLITE_MASTER table:

sqlite> .tab
job         snmptarget  t1          t2          t3        
sqlite> select name from sqlite_master where type = 'table';
job
t1
t2
snmptarget
t3

sqlite> .schema job
CREATE TABLE job (
    id INTEGER PRIMARY KEY,
    data VARCHAR
);
sqlite> select sql from sqlite_master where type = 'table' and name = 'job';
CREATE TABLE job (
    id INTEGER PRIMARY KEY,
    data VARCHAR
)

Answer 2

I'm not familiar with the Python API but you can always use

SELECT * FROM sqlite_master;

Answer 3

After a lot of fiddling I found a better answer at sqlite docs for listing the metadata for the table, even attached databases.

meta = cursor.execute("PRAGMA table_info('Job')")
for r in meta:
    print r

The key information is to prefix table_info, not my_table with the attachment handle name.

Answer 4

In Python:

con = sqlite3.connect('database.db')
cursor = con.cursor()
cursor.execute("SELECT name FROM sqlite_master WHERE type='table';")
print(cursor.fetchall())

Watch out for my other answer. There is a much faster way using pandas.

Answer 5

Here's a short and simple python program to print out the table names and the column names for those tables.

import sqlite3

db_filename = 'database.sqlite'
newline_indent = '\n   '

db=sqlite3.connect(db_filename)
db.text_factory = str
cur = db.cursor()

result = cur.execute("SELECT name FROM sqlite_master WHERE type='table';").fetchall()
table_names = sorted(zip(*result)[0])
print "\ntables are:"+newline_indent+newline_indent.join(table_names)

for table_name in table_names:
    result = cur.execute("PRAGMA table_info('%s')" % table_name).fetchall()
    column_names = zip(*result)[1]
    print ("\ncolumn names for %s:" % table_name)+newline_indent+(newline_indent.join(column_names))

db.close()
print "\nexiting."

Answer 6

I've implemented a sqlite table schema parser in PHP, you may check here: https://github.com/c9s/LazyRecord/blob/master/src/LazyRecord/TableParser/SqliteTableDefinitionParser.php

You can use this definition parser to parse the definitions like the code below:

$parser = new SqliteTableDefinitionParser;
$parser->parseColumnDefinitions('x INTEGER PRIMARY KEY, y DOUBLE, z DATETIME default \'2011-11-10\', name VARCHAR(100)');