sqlalchemy.testing.requirements.SuiteRequirements

Test environment must allow ad-hoc engine/connection creation.

DBs that scale poorly for many connections, even when closed, i.e. Oracle, may use the "--low-connections" option which flags this requirement as not present.

target backend supports simple binary literals, e.g. an expression like:

SELECT CAST('foo' AS BINARY)

Where BINARY is the type emitted from .LargeBinary, e.g. it could be BLOB or similar.

Basically fails on Oracle.

Undocumented

Undocumented

Undocumented

Undocumented

Undocumented

target dialect retrieves cursor.lastrowid, or fetches from a database-side function after an insert() construct executes, within the get_lastrowid() method.

Only dialects that "pre-execute", or need RETURNING to get last inserted id, would return closed/fail/skip for this.

backend supports fetch / offset with expression in them, like

SELECT * FROM some_table OFFSET 1 + 1 ROWS FETCH FIRST 1 + 1 ROWS ONLY

target backend doesn't crash when you try to select a NUMERIC value that has a value of NULL.

Added to support Pyodbc bug #351.

target platform will allow cursor.fetchone() to proceed after a COMMIT.

Typically this refers to an INSERT statement with RETURNING which is invoked within "autocommit". If the row can be returned after the autocommit, then this rule can be open.

Undocumented

Undocumented

Undocumented

Target supports refleciton of FOREIGN KEY constraints and will return the name of the constraint that was used in the "CONSTRAINT <name> FOREIGN KEY" DDL.

MySQL prior to version 8 and MariaDB prior to version 10.5 don't support this.

Undocumented

Undocumented

Undocumented

Undocumented

target platform supports SQL expressions in GROUP BY

e.g.

SELECT x + y AS somelabel FROM table GROUP BY x + y

target backend will return a selected Decimal as a Decimal, not a string.

e.g.:

expr = decimal.Decimal("15.7563")

value = e.scalar(
    select(literal(expr))
)

assert value == expr

See :ticket:`4036`

target system has a strong concept of 'default' schema that can be referred to implicitly.

basically, PostgreSQL.

Undocumented

Undocumented

Undocumented

target dialect supports general isolation level settings.

Note that this requirement, when enabled, also requires that the get_isolation_levels() method be implemented.

Undocumented

Backend has a JSON_EXTRACT or similar function that returns a valid JSON string in all cases.

Used to test a legacy feature and is not needed.

Undocumented

Test should be skipped if coverage is enabled.

This is to block tests that exercise libraries that seem to be sensitive to coverage, such as PostgreSQL notice logging.

Undocumented

Undocumented

Undocumented

target database supports ordering by a column from a SELECT inside of a UNION

E.g. (SELECT id, ...) UNION (SELECT id, ...) ORDER BY id

Undocumented

target backend supports ORDER BY a column label within an expression.

Basically this:

select data as foo from test order by foo || 'bar'

Lots of databases including PostgreSQL don't support this, so this is off by default.

Target database must support parenthesized SELECT in UNION when LIMIT/OFFSET is specifically present.

E.g. (SELECT ...) UNION (SELECT ..)

This is known to fail on SQLite.

Target database must support parenthesized SELECT in UNION when OFFSET/LIMIT is specifically not present.

E.g. (SELECT ... LIMIT ..) UNION (SELECT .. OFFSET ..)

This is known to fail on SQLite. It also fails on Oracle because without LIMIT/OFFSET, there is currently no step that creates an additional subquery.

Undocumented

Undocumented

target backend supports weird identifiers with percent signs in them, e.g. 'some % column'.

this is a very weird use case but often has problems because of DBAPIs that use python formatting. It's not a critical use case either.

Undocumented

Undocumented

Undocumented

Undocumented

Undocumented

Undocumented

Undocumented

target platform supports RETURNING for at least one row.

Undocumented

Undocumented

Undocumented

Undocumented

Undocumented

Undocumented

Target database passes SQL-92 style statements to cursor.execute() when a statement like select() or insert() is run.

A very small portion of dialect-level tests will ensure that certain conditions are present in SQL strings, and these tests use very basic SQL that will work on any SQL-like platform in order to assert results.

It's normally a given for any pep-249 DBAPI that a statement like "SELECT id, name FROM table WHERE some_table.id=5" will work. However, there are dialects that don't actually produce SQL Strings and instead may work with symbolic objects instead, or dialects that aren't working with SQL, so for those this requirement can be marked as excluded.

Supports some form of "x IS [NOT] DISTINCT FROM y" construct. Different dialects will implement their own flavour, e.g., sqlite will emit "x IS NOT y" instead of "x IS DISTINCT FROM y".

target database / driver supports cursor.lastrowid as a means of retrieving the last inserted primary key value.

note that if the target DB supports sequences also, this is still assumed to work. This is a new use case brought on by MariaDB 10.3.

Database / dialect supports a query like:

SELECT * FROM VALUES ( (c1, c2), (c1, c2), ...)
AS some_table(col1, col2)

SQLAlchemy generates this with the _sql.values function.

Undocumented

Undocumented

Undocumented

Target must support UPDATE (or DELETE) where the same table is present in a subquery in the WHERE clause.

This is an ANSI-standard syntax that apparently MySQL can't handle, such as:

UPDATE documents SET flag=1 WHERE documents.title IN
    (SELECT max(documents.title) AS title
        FROM documents GROUP BY documents.user_id
    )

target database must support retrieval of the columns in a view, similarly to how a table is inspected.

This does not include the full CREATE VIEW definition.