initial creation

py3interm/EXAMPLES/db_postgres_metadata.py

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+#!/usr/bin/env python
+
+import psycopg2
+
+DB_HOST = 'localhost'
+DB_USER = 'postgres'
+DB_PASSWORD = 'scripts'
+
+TABLE_QUERY = '''
+    select table_name
+    from information_schema.tables
+    where table_schema = 'public'
+'''
+
+COLUMN_QUERY = '''
+    select column_name, data_type, is_nullable, column_default
+    from information_schema.columns
+    where
+        table_name = %s
+        and
+        table_schema = 'public'
+'''
+
+
+def main(database_name):
+    try:
+        pgcursor = connect_to_dbserver(database_name)
+    except Exception as err:
+        print("Unable to connection to {}: {}".format(database_name, err))
+
+    tables = get_all_tables_from_database(pgcursor, database_name)
+
+    for table in tables:
+        print(table)
+        columns = get_columns_for_table(pgcursor, table, database_name)
+        if columns:
+            column_data_format = '\t{:15} {:20} {:3} {:10}'
+            for col_name, col_type, is_nullable, default_value in columns:
+                print(column_data_format.format(col_name, col_type, is_nullable, default_value))
+
+
+def connect_to_dbserver(database_name):
+    try:
+        with psycopg2.connect(
+            host=DB_HOST,
+            dbname=database_name,
+            user=DB_USER,
+            password=DB_PASSWORD,
+        ) as pgconn:
+            return pgconn.cursor()
+    except Exception as err:
+        print(err)
+        raise err
+
+
+def get_all_tables_from_database(pgcursor, database):
+    pgcursor.execute(TABLE_QUERY, (database,))
+
+    return [row[0] for row in pgcursor.fetchall()]
+
+
+def get_columns_for_table(pgcursor, table_name, database_name):
+    try:
+        pgcursor.execute(COLUMN_QUERY, (table_name,))
+    except psycopg2.ProgrammingError as err:
+        print("Unable to get columns:", err)
+    else:
+        return pgcursor.fetchall()
+
+
+if __name__ == '__main__':
+    main('postgres')