SQL statements API¶
PGMob uses internal classes that wrap plaintext SQL queries and ensure safe parameter validation. These classes are eventually decoded by adapters into SQL statements with appropriate syntax, parameters and quotation.
- class pgmob.sql.Composable¶
Common interface for SQL-like objects
- class pgmob.sql.Composed(*args: Composable)¶
Composed object. Finalized state of co-joined query parts. Can be iterated upon to retrieve the individual parts in proper order.
- class pgmob.sql.Identifier(identifier: str)¶
A database Identifier. Ensures proper quoting for identifiers.
- Parameters:
identifier (str) – identifier name
- compose() Composed¶
Method utilized by an adapter to retrieve a Composed object that contains a list of objects and is ready to be iterated upon. All iterated objects are guaranteed to be one of: SQL, Literal, Identifier.
- Returns:
a composed iterable object
- Return type:
- value() object¶
Retrieve the underlying value of a Composable: a query string, identifier name or a value of a literal. Not supported on Composed objects, which need to be iterated upon first before calling .value() on the yielded Composable objects.
- Returns:
the underlying object in a Composable
- Return type:
object
- class pgmob.sql.Literal(literal: object)¶
A Literal query parameter. Ensures proper quoting for literal values.
- Parameters:
literal (object) – literal value
- compose() Composed¶
Method utilized by an adapter to retrieve a Composed object that contains a list of objects and is ready to be iterated upon. All iterated objects are guaranteed to be one of: SQL, Literal, Identifier.
- Returns:
a composed iterable object
- Return type:
- value() object¶
Retrieve the underlying value of a Composable: a query string, identifier name or a value of a literal. Not supported on Composed objects, which need to be iterated upon first before calling .value() on the yielded Composable objects.
- Returns:
the underlying object in a Composable
- Return type:
object
- class pgmob.sql.SQL(statement: str)¶
A sql statememt
- Parameters:
statement (str) – query text
- compose() Composed¶
Method utilized by an adapter to retrieve a Composed object that contains a list of objects and is ready to be iterated upon. All iterated objects are guaranteed to be one of: SQL, Literal, Identifier.
- Returns:
a composed iterable object
- Return type:
- format(*args: Composable, **kwargs: Composable) Composed¶
Format a query that contains a string formatter argument notation. Format values can be one of: Identifier, Literal.
- Parameters:
*args – for {} or {0} notation
**kwargs – for {keyword} notation
- Returns:
a composed query object
- Return type:
Example
- sql = SQL(“SELECT {column} FROM {table} WHERE id = {value}”).format(
column=Identifier(“col1”), table=Identifier(“mytable”), value=Literal(1)
)
- join(iter: Sequence[Composable]) Composed¶
Joins basic query building blocks, such as SQL, Literal, Identifier.
- Parameters:
iter – an iterable containing Composable elements
- Returns:
a composed query object
- Return type:
Example
sql = SQL(“SELECT col FROM “) + SQL(“.”).join(Identifier(“myschema”),Identifier(“mytable”))
- value() object¶
Retrieve the underlying value of a Composable: a query string, identifier name or a value of a literal. Not supported on Composed objects, which need to be iterated upon first before calling .value() on the yielded Composable objects.
- Returns:
the underlying object in a Composable
- Return type:
object