Get connection schema

Internal Matcher connection identifier the schema belongs to

How the field lists in this map were obtained, recorded per row by the report that produced it and folded to one answer for the map: ENUMERATED means they come from the source's own catalog and are exhaustive for the credential that read it, so fewer fields than before is a real change in what the source reports; SAMPLED means they are inferred from a sample of the source's data (MongoDB reads the union of top-level keys over $sample-d documents), so they vary between reads with nothing changed at the source and no reduction is ever asserted from them — how the persisted field lists then build up, and what ends that, is stated in full in this operation's description. It is NEVER derived from this connection's current databaseType, which an operator can edit: a retype must not re-attribute field sets a different connector produced. Present only when every row of the map records the same kind: absent when the rows disagree, when any of them predates the recording of this fact, and when the probe that installed them could not show which connector produced its snapshot — in each case nothing is asserted about how the fields were obtained. It is the fact that separates routes (1) and (5) of notYetExtractableReason, whose remedies contradict each other

The tables are a retired generation, not the connection's live map: the source has not re-asserted them since they were archived. Absent when the rows served are live

When the map was last successfully read from the source; absent when no map has ever been read

Why nothing in this map can be extracted from yet; absent when at least one table can. COLUMNS_NOT_ENUMERATED means Matcher holds no confirmed column observation for this connection that it could project into an extraction, and it arrives by five routes worth distinguishing, each named here so a client can tie an operator-facing sentence to one: (1) TABLES_WITHOUT_COLUMNS — every persisted table carries no column, the only route visible in the tables below; (2) COLUMNS_NEVER_CONFIRMED — no probe of this connection ever recorded a confirmed-columns observation, in which case the tables below may still show columns; (3) COLUMN_VISIBILITY_LOST — an established connection whose source enumerates its columns from a catalog returned columns for no table it still names, so that snapshot was refused and the tables below show their last confirmed columns; (4) NO_TABLES_NAMED — the source named no table at all; (5) SAMPLED_REPORT_NO_FIELDS — the source's field list is sampled from its data rather than enumerated from a catalog and the draw returned no field, so nothing was refused: the tables installed, no column was confirmed, and extraction reopens as soon as a draw returns fields. Routes 3, 4 and 5 arrive as the same response and a client states them as readings rather than picking one. Routes 1 and 5 also arrive as the same response — a map in which every table carries no column — and their remedies contradict each other, so fieldReport above says which of the two applies: SAMPLED is route 5 and no grant is involved, ENUMERATED is route 1 and the credential's column grants are the thing to check. Both must be stated when fieldReport is absent, which happens when the rows of this map disagree about how their field lists were obtained, when any of them predates the recording of that fact, or when the probe that installed them could not show which connector produced its snapshot — the connector registry is not consulted on this path at all, so a registered connector is neither what makes the kind present nor what its absence says anything about. No route distinguishes a source with no columns to give from columns this connection's credential can no longer read

The connection could not be reached when this map was served: the tables are the last known map and may no longer match the source