Difference between revisions of "Python:Databases"
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Line 7: | Line 7: | ||
;cnx = mysql.connector.connect(**cnxconfig) | ;cnx = mysql.connector.connect(**cnxconfig) | ||
− | :Open database as defined in the cnxconfig dictionary. The ** passes the dictionary unpacked to a function. | + | :Open MySQL database as defined in the cnxconfig dictionary. See example below. The ** passes the dictionary unpacked to a function. |
+ | |||
+ | ;import cx_Oracle | ||
+ | :Load module for oracle | ||
+ | |||
+ | ;cnx = cx_Oracle.connect(user=dbuser, password=dbpasswd, dsn=dbtns_alias) | ||
+ | :Open Oracle database. | ||
;cursor = cnx.cursor() | ;cursor = cnx.cursor() |
Revision as of 11:03, 18 September 2019
See below for an example script
- import mysql.connector
- Load module for mysql
- cnx = mysql.connector.connect(**cnxconfig)
- Open MySQL database as defined in the cnxconfig dictionary. See example below. The ** passes the dictionary unpacked to a function.
- import cx_Oracle
- Load module for oracle
- cnx = cx_Oracle.connect(user=dbuser, password=dbpasswd, dsn=dbtns_alias)
- Open Oracle database.
- cursor = cnx.cursor()
- Create a cursor that returns rows in a tuple
- cursor = cnx.cursor(dictionary=True)
- Create a cursor that returns rows in a dictionary { column1: value1, column2: value2 }
- cursor.execute(query)
- Execute 'query'. Columnames are in the tuple cursor.column_names. Traverse the cursor to fetch the data. The cursor returns a tuple for each row.
- cursor.rowcount
- The number of rows affected by this query.
- cursor.fetchone()
- Return the next row from the cursor result.
- cursor.fetchmany(size=2)
- Return the first two rows of the result in a list.
- cursor.fetchall()
- Return all (remaining) rows of the result in a list.
for row in cursor:
print(row)
for column in row:
print(column)
- cursor.close()
- Close the cursor
- cnx.close()
- Close the database connection
Code example showing all:
import mysql.connector
cnxconfig = {
'host': 'hostname',
'port': 3306,
'user': 'username',
'password': '',
'database': 'DBname'
}
#cnx = mysql.connector.connect(host='hostname', port=3306, user='username', database='DBname')
cnx = mysql.connector.connect(**cnxconfig)
if cnx:
print("Connection, continue")
else:
print("No connection, exit")
exit()
print("Tuple cursor")
cursor = cnx.cursor()
query = ("SELECT * FROM table")
cursor.execute(query)
for columname in cursor.column_names:
print(columname)
for row in cursor:
print(row)
for column in row:
print(column)
print("Dictionary cursor")
cursor = cnx.cursor(dictionary=True)
cursor.execute(query)
for row in cursor:
for columname in row.keys():
print("{0:25s}: {1:}".format(columname, row[columname]))
cursor.close()
cnx.close()