SQL Backend Base Classes

BaseSQLBackend

Bases: BaseBackend

Base backend class for backends that compile to SQL.

Functions

compile(expr, limit=None, params=None, timecontext=None)

Compile an Ibis expression.

Parameters:

Name	Type	Description	Default
expr	ir.Expr	Ibis expression	required
limit	str | None	For expressions yielding result sets; retrieve at most this number of values/rows. Overrides any limit already set on the expression.	None
params	Mapping[ir.Expr, Any] | None	Named unbound parameters	None
timecontext	tuple[pd.Timestamp, pd.Timestamp] | None	Additional information about data source time boundaries	None

Returns:

Type	Description
Any	The output of compilation. The type of this value depends on the backend.

execute(expr, params=None, limit='default', **kwargs)

Compile and execute an Ibis expression.

Compile and execute Ibis expression using this backend client interface, returning results in-memory in the appropriate object type

Parameters:

Name	Type	Description	Default
expr	ir.Expr	Ibis expression	required
limit	str	For expressions yielding result sets; retrieve at most this number of values/rows. Overrides any limit already set on the expression.	'default'
params	Mapping[ir.Scalar, Any] | None	Named unbound parameters	None
kwargs	Any	Backend specific arguments. For example, the clickhouse backend uses this to receive external_tables as a dictionary of pandas DataFrames.	{}

Returns:

Type	Description
DataFrame | Series | Scalar	Table: pandas.DataFrame Column: pandas.Series Scalar: Python scalar value

explain(expr, params=None)

Explain an expression.

Return the query plan associated with the indicated expression or SQL query.

Returns:

Type	Description
str	Query plan

raw_sql(query)

Execute a query string.

The returned cursor object must be manually released if results are returned.

Parameters:

Name	Type	Description	Default
query	str	DDL or DML statement	required

sql(query, schema=None)

Convert a SQL query to an Ibis table expression.

Parameters:

Name	Type	Description	Default
query	str	SQL string	required
schema	sch.Schema | None	The expected schema for this query. If not provided, will be inferred automatically if possible.	None

Returns:

Type	Description
Table	Table expression

table(name, database=None)

Construct a table expression.

Parameters:

Name	Type	Description	Default
name	str	Table name	required
database	str | None	Database name	None

Returns:

Type	Description
Table	Table expression

to_pyarrow_batches(expr, *, params=None, limit=None, chunk_size=1000000, **_)

Execute expression and return an iterator of pyarrow record batches.

This method is eager and will execute the associated expression immediately.

Parameters:

Name	Type	Description	Default
expr	ir.Expr	Ibis expression to export to pyarrow	required
limit	int | str | None	An integer to effect a specific row limit. A value of None means "no limit". The default is in ibis/config.py.	None
params	Mapping[ir.Scalar, Any] | None	Mapping of scalar parameter expressions to value.	None
chunk_size	int	Maximum number of rows in each returned record batch.	1000000

Returns:

Type	Description
RecordBatchReader	Collection of pyarrow RecordBatchs.

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Last update: January 4, 2023