Clearly state the value range of all integer type fields in the model field documentation

[Markus Amalthea Magnuson]

The documentation for BigIntegerField, PositiveSmallIntegerField and SmallIntegerField clearly state what integer values fit into that field's size:

​https://docs.djangoproject.com/en/dev/ref/models/fields/#bigintegerfield
​https://docs.djangoproject.com/en/dev/ref/models/fields/#positivesmallintegerfield
​https://docs.djangoproject.com/en/dev/ref/models/fields/#smallintegerfield

But these do not state the same info:

​https://docs.djangoproject.com/en/dev/ref/models/fields/#integerfield
​https://docs.djangoproject.com/en/dev/ref/models/fields/#positiveintegerfield

For clarity, I think all of the above fields should be documented with a standardized sentence like this:

"Values from X to Y are safe in all databases supported by Django."

[Markus Amalthea Magnuson]

Opened a pull request here: ​https://github.com/django/django/pull/1949

[Tim Graham]

Assuming the ranges are correct, this looks good. Could you amend your PR to follow the ​commit message guidelines? Also, don't forget to check "Has patch" so the ticket appears in the review queue. Thanks!

[Claude Paroz]

Sorry, but I'd like to know where do the new figures come from. Could you please document here your findings (with appropriate links to backends documentation)?

[Markus Amalthea Magnuson]

Sorry, I did not do my homework properly, and the values were not correct.

I've now corrected them and opened a new pull request (following commit message guidelines): ​https://github.com/django/django/pull/1955

The values and their sources are as follows:

MySQL
IntegerField (integer): -2147483648 to 2147483647
PositiveIntegerField (integer UNSIGNED): 0 to 2147483647
PositiveSmallIntegerField (smallint UNSIGNED): 0 to 32767
Source: ​http://dev.mysql.com/doc/refman/5.0/en/integer-types.html

Postgres
IntegerField (integer): -2147483648 to 2147483647
PositiveIntegerField (integer): 0 to 2147483647
PositiveSmallIntegerField (smallint): 0 to 32767
Source: ​http://www.postgresql.org/docs/devel/static/datatype-numeric.html

Oracle
IntegerField (NUMBER(11)): -99999999999 to 99999999999
PositiveIntegerField (NUMBER(11)): 0 to 99999999999
PositiveSmallIntegerField (NUMBER(11)): 0 to 99999999999
Source: ​http://docs.oracle.com/cd/E11882_01/server.112/e25513/limits001.htm

SQLite
("1, 2, 3, 4, 6, or 8 bytes depending on the magnitude of the value.")
IntegerField (integer): -9223372036854775808 to 9223372036854775807
PositiveIntegerField (integer unsigned): 0 to 9223372036854775807
PositiveSmallIntegerField (smallint unsigned): 0 to 9223372036854775807
Source: ​http://www.sqlite.org/datatype3.html

[Baptiste Mispelon]

Everything looks good.

Thanks for finding all the references too, this is very valuable.

I'll mark the ticket as ready for checkin and commit it later today if no one does it before.

[Baptiste Mispelon <bmispelon@…>]

In b6a6cf4ab791b092e18ab16537aa88dd7ae9bc36:

Fixed #21427 -- Clearly state integer field value ranges in docs

Added an explicit mention of the exact value ranges for integer type
fields that are safe in all databases supported by Django. Also, put
all value numbers inside double ticks.

[Baptiste Mispelon <bmispelon@…>]

In 47abfa237e21ca71d8ee901cf8ba1f1c89ae1f2e:

[1.6.x] Fixed #21427 -- Clearly state integer field value ranges in docs

Added an explicit mention of the exact value ranges for integer type
fields that are safe in all databases supported by Django. Also, put
all value numbers inside double ticks.

Backport of b6a6cf4ab791b092e18ab16537aa88dd7ae9bc36 from master.