Hi, thanks for the detailed reply.
My task was to detect the required fields to generate the schema. It looks
like it is better to not require field when autoincrement is 'auto'. (And
of course, take into account client/server-side defaults)
On Monday, 17 February 2020 20:56:01 UTC+7, Kotofos online wrote:
>
> Hi, i'm having a troubles detecting auto-increment on reflected tables
> across different db types.
>
> There is same manually created table in multiple databases of different
> type:
>
> sqlite3 test.db 'create table project (id int primary key not null)'
>
> Then reflect it. After reflection, I can check for column attribute
> autoincrement.
> But sometimes column.autoincrement is 'auto' instead of true/false.
>
> from sqlalchemy import create_engine
>
> from sqlalchemy.ext.automap import automap_base
>
> engine = create_engine('sqlite:///../test.db')
> Base = automap_base()
> Base.prepare(engine, reflect=True)
>
> cls = Base.classes['project']
> print cls.id.prop.columns[0].autoincrement
>
>
> In my case for db2, oracle, sqlite it is 'auto'. For mysql, mssql,
> postglesql it is false.
> As I saw in documentation, this 'auto' is useful when defining tables
> manually. But what it does on reflected tables?.
>
> The default value is the string "auto" which indicates that a
>> single-column primary key that is of an INTEGER type with no stated
>> client-side or python-side defaults should receive auto increment semantics
>> automatically; all other varieties of primary key columns will not. This
>> includes that DDL
>> <https://docs.sqlalchemy.org/en/13/glossary.html#term-ddl> such as
>> PostgreSQL SERIAL or MySQL AUTO_INCREMENT will be emitted for this column
>> during a table create, as well as that the column is assumed to generate
>> new integer primary key values when an INSERT statement invokes which will
>> be retrieved by the dialect.
>>
>> https://docs.sqlalchemy.org/en/13/core/metadata.html#sqlalchemy.schema.Column.params.autoincrement
>>
>
> So, how to properly check is column auto incremented or not?
>
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