When Is Primary Key Generated Sqlalchemy

When Is Primary Key Generated Sqlalchemy Average ratng: 5,6/10 9040 reviews

Q&A for Work. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. Changed in version 1.0.0: an INSERT that uses FROM SELECT implies that the insert.inline flag is set to True, indicating that the statement will not attempt to fetch the “last inserted primary key” or other defaults. The statement deals with an arbitrary number of rows, so the ResultProxy.insertedprimarykey accessor does not apply.

  • SQLAlchemy Tutorial
  • SQLAlchemy Core
  • SQLAlchemy ORM
  • SQLAlchemy Useful Resources
  • Selected Reading

All SELECT statements generated by SQLAlchemy ORM are constructed by Query object. It provides a generative interface, hence successive calls return a new Query object, a copy of the former with additional criteria and options associated with it.

Query objects are initially generated using the query() method of the Session as follows −

Following statement is also equivalent to the above given statement −

The query object has all() method which returns a resultset in the form of list of objects. If we execute it on our customers table −

This statement is effectively equivalent to following SQL expression −

The result object can be traversed using For loop as below to obtain all records in underlying customers table. Here is the complete code to display all records in Customers table −

Python console shows list of records as below −

When Is Primary Key Generated Sqlalchemy In Excel

The Query object also has following useful methods −

Pengertian Primary Key

Sr.No.Method & Description
1

add_columns()

It adds one or more column expressions to the list of result columns to be returned.

2

add_entity()

It adds a mapped entity to the list of result columns to be returned.

3

count()

It returns a count of rows this Query would return.

4

delete()

It performs a bulk delete query. Deletes rows matched by this query from the database.

5

distinct()

It applies a DISTINCT clause to the query and return the newly resulting Query.

6

filter()

It applies the given filtering criterion to a copy of this Query, using SQL expressions.

7

first()

It returns the first result of this Query or None if the result doesn’t contain any row.

8

get()

It returns an instance based on the given primary key identifier providing direct access to the identity map of the owning Session.

9

group_by()

It applies one or more GROUP BY criterion to the query and return the newly resulting Query

10

join()Vmware vcenter 5.1 license key generator.

It creates a SQL JOIN against this Query object’s criterion and apply generatively, returning the newly resulting Query.

11

one()

It returns exactly one result or raise an exception.

12

order_by()

It applies one or more ORDER BY criterion to the query and returns the newly resulting Query.

13

update()

It performs a bulk update query and updates rows matched by this query in the database.