initial creation

py3interm/EXAMPLES/db_sqlite_metadata.py

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+#!/usr/bin/env python
+
+"""
+    Provide metadata (tables and column names) for a Sqlite3 database
+"""
+
+import sqlite3
+
+TABLE_QUERY = '''
+    select name
+    from sqlite_master
+    order by name
+'''
+
+
+def main(database_file):
+    """
+        Program entry point
+
+        PARAMS:
+        database_file: name of Sqlite database file
+    """
+    mycursor = connect_to_dbserver(database_file)
+    tables = get_all_tables_from_database(mycursor)
+    print('-' * 60)
+    for table in tables:
+        print(table)
+        columns = get_columns_for_table(mycursor, table)
+        for col_name, col_type, is_nullable, default_value in columns:
+            print(col_name, col_type, is_nullable, default_value)
+
+
+def connect_to_dbserver(database_file):
+    """
+        Connect to specified Sqlite3 database
+
+        PARAMS:
+        database_file: name of Sqlite3 database file to query
+    """
+    with sqlite3.connect(database_file) as s3conn:
+        return s3conn.cursor()
+
+
+def get_all_tables_from_database(mycursor):
+    """
+        Get list of tables in database
+
+        PARAMS:
+        mycursor: open Sqlite3 database cursor
+
+        :rtype : list of table names
+    """
+
+    mycursor.execute(TABLE_QUERY)
+
+    return [row[0] for row in mycursor.fetchall() if not row[0].startswith('sqlite')]
+
+
+def get_columns_for_table(mycursor, table_name):
+    """
+        Get list of columns and metadata for specified table
+
+        PARAMS:
+        mycursor: open Sqlite3 database cursor
+        table_name: table for which to return columns
+
+        CAUTION: do not pass unverified information to this function;
+        it is not checked for SQL injection issues
+
+        :rtype : list of lists, each with name, type, nullable flag, and default value
+    """
+
+    mycursor.execute('pragma table_info({})'.format(table_name))
+    return [row[1:-1] for row in mycursor.fetchall()]  # 1st column is ordinal; last is PK flag
+
+
+if __name__ == '__main__':
+    main("../DATA/presidents.db")