lancedb_haystack.filters

Attributes

COMPARISON_OPERATORS

Functions

convert_filters_to_where_clause(→ str)	Convert Haystack filters to a WHERE clause and a tuple of params to query PostgreSQL.
_parse_logical_condition(→ str)	Compose the sub-queries of a logical step
_parse_comparison_condition(→ str)	Identifies and applies the right comparison function.
equal(→ str)	Construct a query string for comparing equality between a field and a value.
not_equal(→ str)	Construct a query string for filtering when a field and a value are not equal
greater_than(→ str)	Construct a query string for filtering when a field is greater than the value.
greater_than_equal(→ str)	Construct a query string for filtering when a field is greater than or equal to the value.
less_than(→ str)	Construct a query string for filtering when a field is less than to the value.
less_than_equal(→ str)	Construct a query string for filtering when a field is less than or equal to the value.
not_in(→ str)	Construct a query string for filtering when a field's value is not in a provided list.
in_(→ str)	Construct a query string for filtering when a field's value is in a provided list.
is_null(→ str)	Construct Filter term for the field being either empty or Null
is_not_null(→ str)	Construct Filter term for the field being neither empty nor Null

Module Contents

lancedb_haystack.filters.convert_filters_to_where_clause(filters: Dict[str, Any]) → str

Convert Haystack filters to a WHERE clause and a tuple of params to query PostgreSQL.

Parameters:

filters – the filters to convert. See: https://docs.haystack.deepset.ai/docs/metadata-filtering

Returns:

a string containing the LanceDB where clause.

lancedb_haystack.filters._parse_logical_condition(condition: Dict[str, Any]) → str

Compose the sub-queries of a logical step

lancedb_haystack.filters._parse_comparison_condition(condition: Dict[str, Any]) → str

Identifies and applies the right comparison function.

Parameters:

condition – The condition term to convert

Returns:

a string containing the comparison for use in a LanceDB where clause

lancedb_haystack.filters.equal(field: str, value: Any) → str

Construct a query string for comparing equality between a field and a value.

Parameters:

• field – the field to compare

• value – the value to compare it to.

Returns:

a comparison string.

lancedb_haystack.filters.not_equal(field: str, value: Any) → str

Construct a query string for filtering when a field and a value are not equal

Parameters:

• field – the field to compare

• value – the value to compare it to.

Returns:

a comparison string.

lancedb_haystack.filters.greater_than(field: str, value: Any) → str

Construct a query string for filtering when a field is greater than the value.

Note: ‘greater_than’ comparisons to None always evaluate to false.

Parameters:

• field – the field to compare

• value – the value to compare it to.

Returns:

a comparison string.

Raises:

FilterError – if value is a DataFrame, string, list or dict which are not supported for this comparison.

lancedb_haystack.filters.greater_than_equal(field: str, value: Any) → str

Construct a query string for filtering when a field is greater than or equal to the value.

Note: ‘greater_than_equal’ comparisons to None always evaluate to false.

Parameters:

• field – the field to compare

• value – the value to compare it to.

Returns:

a comparison string.

Raises:

FilterError – if value is a DataFrame, string, list or dict which are not supported for this comparison.

lancedb_haystack.filters.less_than(field: str, value: Any) → str

Construct a query string for filtering when a field is less than to the value.

Note: ‘less_than’ comparisons to None always evaluate to false.

Parameters:

• field – the field to compare

• value – the value to compare it to.

Returns:

a comparison string.

Raises:

FilterError – if value is a DataFrame, string, list or dict which are not supported for this comparison.

lancedb_haystack.filters.less_than_equal(field: str, value: Any) → str

Construct a query string for filtering when a field is less than or equal to the value.

Note: ‘less_than_equal’ comparisons to None always evaluate to false.

Parameters:

• field – the field to compare

• value – the value to compare it to.

Returns:

a comparison string.

Raises:

FilterError – if value is a DataFrame, string, list or dict which are not supported for this comparison.

lancedb_haystack.filters.not_in(field: str, value: Any) → str

Construct a query string for filtering when a field’s value is not in a provided list.

Parameters:

• field – the field to filter on

• value – the list of values.

Returns:

a comparison string.

Raises:

FilterError – if value is not a list.

lancedb_haystack.filters.in_(field: str, value: Any) → str

Construct a query string for filtering when a field’s value is in a provided list.

Parameters:

• field – the field to filter on

• value – the list of values.

Returns:

a comparison string.

Raises:

FilterError – if value is not a list.

lancedb_haystack.filters.is_null(field: str) → str

Construct Filter term for the field being either empty or Null

Parameters:

field – the field to check for being null

Returns:

the filter string

lancedb_haystack.filters.is_not_null(field: str) → str

Construct Filter term for the field being neither empty nor Null

Parameters:

field – the field to check for being null

Returns:

the filter string

lancedb_haystack.filters.COMPARISON_OPERATORS