spanner-session-implicit-txn-usage.rst

Implicit Transactions

The following operations on a session to not require creating an explicit :class:`~google.cloud.spanner.snapshot.Snapshot` or :class:`~google.cloud.spanner.transaction.Transaction`.

Read Table Data

Read data for selected rows from a table in the session's database. Calls the Read API, which returns all rows specified in key_set, or else fails if the result set is too large,

result = session.read(
    table='table-name', columns=['first_name', 'last_name', 'age'],
    key_set=['phred@example.com', 'bharney@example.com'])

for row in result.rows:
    print(row)

Note

If streaming a chunk fails due to a "resumable" error, :meth:`Session.read` retries the StreamingRead API reqeust, passing the resume_token from the last partial result streamed.

Execute a SQL Select Statement

Read data from a query against tables in the session's database. Calls the ExecuteSql API, which returns all rows matching the query, or else fails if the result set is too large,

QUERY = (
    'SELECT e.first_name, e.last_name, p.telephone '
    'FROM employees as e, phones as p '
    'WHERE p.employee_id == e.employee_id')
result = session.execute_sql(QUERY)

for row in result.rows:
    print(row)

Next Step

Next, learn about :doc:`spanner-batch-usage`.