Power Query: connectors

Connecting to Postgres, SQL Server, OData, and web sources: testing the connection, previewing, and navigating objects. Terms are in the glossary.

Session mode only

The processor has no network of its own: the build has no TLS, and it can’t negotiate https. So anything that reaches outside works only when launched with the --session flag, where a host is on hand, ready to reach the network on the core’s behalf.

In one-shot mode, live providers are deliberately not connected, and the operations refuse honestly instead of pretending there’s no connection: the codes postgres-provider-unavailable and sqlserver-provider-unavailable, and an https request gets tls-error.

What’s needed from the host for this — the counter-lines with a kind field that it responds to — is described in how the session works.

Operations on this page — 13

• evaluate_power_query_odata_feed_transform
• evaluate_power_query_postgres_transform
• evaluate_power_query_sqlserver_transform
• evaluate_power_query_transform
• evaluate_power_query_web_connector_transform
• pq_postgres_cancel
• pq_postgres_list_navigation
• pq_postgres_preview
• pq_postgres_test_connection
• pq_sqlserver_cancel
• pq_sqlserver_list_navigation
• pq_sqlserver_preview
• pq_sqlserver_test_connection

evaluate_power_query_odata_feed_transform

Evaluates a Power Query transform for an OData feed.

Request

Field	TypeScript type	Req.
operation	"evaluate_power_query_odata_feed_transform"	yes
mSource	string	yes
connector	ApprovedODataFeedDescriptor	no
destination	PowerQueryLoadDestination	no
refreshQueryId	string	no
requestedBackend	ComputeBackendKind | null	no

Response on success · evaluate_power_query_odata_feed_transform

Field	TypeScript type	Req.
operation	"evaluate_power_query_odata_feed_transform"	yes
outcome	ContractPowerQueryTransformOutcome	yes
loadPlan	PowerQueryLoadPlan	no

Minimal JSON template

{
  "operation": "evaluate_power_query_odata_feed_transform",
  "mSource": "<string>",
  "requestedBackend": "native-desktop"
}

evaluate_power_query_postgres_transform

Evaluates a Power Query transform for Postgres.

Request

Field	TypeScript type	Req.
operation	"evaluate_power_query_postgres_transform"	yes
descriptor	PqPostgresDialogDescriptor	no
table	PqPostgresPreviewTableRef	no
mSource	string	no
destination	PowerQueryLoadDestination	no
refreshQueryId	string	no
connectUser	string	no
lanGrants	PqPostgresLanGrantWire[]	no
privacy	PqPrivacyEvaluationInput	no
requestedBackend	ComputeBackendKind | null	no

Response on success · evaluate_power_query_postgres_transform

Field	TypeScript type	Req.
operation	"evaluate_power_query_postgres_transform"	yes
outcome	ContractPowerQueryTransformOutcome	yes
loadPlan	PowerQueryLoadPlan	no

Minimal JSON template

{
  "operation": "evaluate_power_query_postgres_transform",
  "requestedBackend": "native-desktop"
}

evaluate_power_query_sqlserver_transform

Evaluates a Power Query transform for SQL Server.

Request

Field	TypeScript type	Req.
operation	"evaluate_power_query_sqlserver_transform"	yes
descriptor	PqSqlServerDescriptor	no
table	PqSqlServerTableRef	no
destination	PowerQueryLoadDestination	no
refreshQueryId	string	no
privacy	PqPrivacyEvaluationInput	no
requestedBackend	ComputeBackendKind | null	no

Response on success · evaluate_power_query_sqlserver_transform

Field	TypeScript type	Req.
operation	"evaluate_power_query_sqlserver_transform"	yes
outcome	ContractPowerQueryTransformOutcome	yes
loadPlan	PowerQueryLoadPlan	no

Minimal JSON template

{
  "operation": "evaluate_power_query_sqlserver_transform",
  "requestedBackend": "native-desktop"
}

evaluate_power_query_transform

Evaluates a Power Query transform.

Request

Field	TypeScript type	Req.	Note from the contract
operation	"evaluate_power_query_transform"	yes
mSource	string	yes
sourceId	string	yes
sourceUri	string	no
sourceKind	"csv" | “workbook” | “folder” | “json” | “xml”	no	For csv and workbook, this is informational — it’s already inferred from the query. For folder, it’s meaningful: it’s exactly what routes processing down the folder-combine path instead of the single-file one.
previewStep	number	no	A preview of an intermediate step; works the same way as for the other Power Query sources.
destination	PowerQueryLoadDestination	no	An optional destination for the result. Without this field, it’s a plain preview with no plan. With it, it’s still a preview, but the response carries a verified load plan in loadPlan; the load itself doesn’t happen.
includeDependencyGraph	boolean	no
paramOptions	ContractPersistedParamOptionsBinding	no
requestedBackend	ComputeBackendKind | null	no

Response on success · evaluate_power_query_transform

Field	TypeScript type	Req.	Note from the contract
operation	"evaluate_power_query_transform"	yes
outcome	ContractPowerQueryTransformOutcome	yes
loadPlan	PowerQueryLoadPlan	no	Present in the response only if the request included a load destination and the computation succeeded. Absent for a plain preview and on a refusal. No data is written anywhere in this case.
recomputed	boolean	no
dependencyGraph	ContractDependencyGraphSnapshot | null	no

Minimal JSON template

{
  "operation": "evaluate_power_query_transform",
  "mSource": "<string>",
  "sourceId": "<string>",
  "requestedBackend": "native-desktop"
}

evaluate_power_query_web_connector_transform

Evaluates a Power Query transform for a web connector.

Request

Field	TypeScript type	Req.
operation	"evaluate_power_query_web_connector_transform"	yes
mSource	string	yes
connector	ApprovedWebConnectorDescriptor	no
destination	PowerQueryLoadDestination	no
refreshQueryId	string	no
requestedBackend	ComputeBackendKind | null	no

Response on success · evaluate_power_query_web_connector_transform

Field	TypeScript type	Req.
operation	"evaluate_power_query_web_connector_transform"	yes
outcome	ContractPowerQueryTransformOutcome	yes
loadPlan	PowerQueryLoadPlan	no

Minimal JSON template

{
  "operation": "evaluate_power_query_web_connector_transform",
  "mSource": "<string>",
  "requestedBackend": "native-desktop"
}

pq_postgres_cancel

Cancels a Postgres request that’s already in progress.

Request

Field	TypeScript type	Req.
operation	"pq_postgres_cancel"	yes
descriptor	PqPostgresDialogDescriptor	no

Response on success · pq_postgres_cancel

Field	TypeScript type	Req.
operation	"pq_postgres_cancel"	yes
acknowledged	boolean	yes

Minimal JSON template

{
  "operation": "pq_postgres_cancel",
  "requestedBackend": "native-desktop"
}

pq_postgres_list_navigation

Lists what’s in Postgres: without a schema specified, the schemas themselves; with one, its tables and views.

Request

Field	TypeScript type	Req.	Note from the contract
operation	"pq_postgres_list_navigation"	yes
descriptor	PqPostgresDialogDescriptor	yes
schema	string	no	Without this field, the root schemas are returned; with it, the tables and views of the given schema.
connectUser	string	no
lanGrants	PqPostgresLanGrantWire[]	no
privacy	PqPrivacyEvaluationInput	no

Response on success · pq_postgres_list_navigation

Field	TypeScript type	Req.	Note from the contract
operation	"pq_postgres_list_navigation"	yes
schemas	PqPostgresNavigationSchemaWire[]	no	Present in the response to a root-schema request.
tables	PqPostgresNavTableWire[]	no	Present in the response to a request for one schema’s tables.
denied	PqPostgresDeniedWire	no

Minimal JSON template

{
  "operation": "pq_postgres_list_navigation",
  "descriptor": "<PqPostgresDialogDescriptor>",
  "requestedBackend": "native-desktop"
}

pq_postgres_preview

A preview of data from Postgres — the first rows, to see its shape.

Request

Field	TypeScript type	Req.
operation	"pq_postgres_preview"	yes
descriptor	PqPostgresDialogDescriptor	yes
table	PqPostgresPreviewTableRef	yes
maxRows	number	no
connectUser	string	no
lanGrants	PqPostgresLanGrantWire[]	no
privacy	PqPrivacyEvaluationInput	no

Response on success · pq_postgres_preview

Field	TypeScript type	Req.	Note from the contract
operation	"pq_postgres_preview"	yes
columns	string[]	no
rows	string[][]	no	Display-projected rows (each cell a string); bounded ≤ min(maxRows, descriptor bound).
truncated	boolean	yes
denied	PqPostgresDeniedWire	no

Minimal JSON template

{
  "operation": "pq_postgres_preview",
  "descriptor": "<PqPostgresDialogDescriptor>",
  "table": "<PqPostgresPreviewTableRef>",
  "requestedBackend": "native-desktop"
}

pq_postgres_test_connection

Tests the connection to Postgres for a given connection, without reading any data.

Request

Field	TypeScript type	Req.
operation	"pq_postgres_test_connection"	yes
descriptor	PqPostgresDialogDescriptor	yes
connectUser	string	no
lanGrants	PqPostgresLanGrantWire[]	no
privacy	PqPrivacyEvaluationInput	no

Response on success · pq_postgres_test_connection

Field	TypeScript type	Req.
operation	"pq_postgres_test_connection"	yes
serverVersion	string	no
denied	PqPostgresDeniedWire	no

Minimal JSON template

{
  "operation": "pq_postgres_test_connection",
  "descriptor": "<PqPostgresDialogDescriptor>",
  "requestedBackend": "native-desktop"
}

pq_sqlserver_cancel

Cancels a SQL Server request that’s already in progress.

Request

Field	TypeScript type	Req.
operation	"pq_sqlserver_cancel"	yes

Response on success · pq_sqlserver_cancel

Field	TypeScript type	Req.
operation	"pq_sqlserver_cancel"	yes
acknowledged	boolean	yes

Minimal JSON template

{
  "operation": "pq_sqlserver_cancel",
  "requestedBackend": "native-desktop"
}

pq_sqlserver_list_navigation

Lists what’s in SQL Server: without a schema specified, the schemas themselves; with one, its tables and views.

Request

Field	TypeScript type	Req.
operation	"pq_sqlserver_list_navigation"	yes
descriptor	PqSqlServerDescriptor	yes
privacy	PqPrivacyEvaluationInput	no

Response on success · pq_sqlserver_list_navigation

Field	TypeScript type	Req.
operation	"pq_sqlserver_list_navigation"	yes
items	PqSqlServerNavigationItemWire[]	no
denied	PqSqlServerDeniedWire	no

Minimal JSON template

{
  "operation": "pq_sqlserver_list_navigation",
  "descriptor": "<PqSqlServerDescriptor>",
  "requestedBackend": "native-desktop"
}

pq_sqlserver_preview

A preview of data from SQL Server — the first rows, to see its shape.

Request

Field	TypeScript type	Req.
operation	"pq_sqlserver_preview"	yes
descriptor	PqSqlServerDescriptor	yes
table	PqSqlServerTableRef	yes
maxRows	number	no
privacy	PqPrivacyEvaluationInput	no

Response on success · pq_sqlserver_preview

Field	TypeScript type	Req.
operation	"pq_sqlserver_preview"	yes
columns	string[]	no
rows	string[][]	no
truncated	boolean	yes
denied	PqSqlServerDeniedWire	no

Minimal JSON template

{
  "operation": "pq_sqlserver_preview",
  "descriptor": "<PqSqlServerDescriptor>",
  "table": "<PqSqlServerTableRef>",
  "requestedBackend": "native-desktop"
}

pq_sqlserver_test_connection

Tests the connection to SQL Server for a given connection, without reading any data.

Request

Field	TypeScript type	Req.
operation	"pq_sqlserver_test_connection"	yes
descriptor	PqSqlServerDescriptor	yes
privacy	PqPrivacyEvaluationInput	no

Response on success · pq_sqlserver_test_connection

Field	TypeScript type	Req.
operation	"pq_sqlserver_test_connection"	yes
serverVersion	string	no
denied	PqSqlServerDeniedWire	no

Minimal JSON template

{
  "operation": "pq_sqlserver_test_connection",
  "descriptor": "<PqSqlServerDescriptor>",
  "requestedBackend": "native-desktop"
}