feat: EHR search table stakes (_has, uri, include wildcards, 2-hop chains)

pkg/postgres/README.md

@@ -145,6 +145,7 @@ Search entries use typed table routing (same convention as sqlite):
 - `token.<name>` → token index
 - `string.<name>` → string index (default when no prefix)
 - `date.<name>`, `number.<name>`, `reference.<name>` / `ref.<name>` → typed tables
+- `uri.<name>` → string index (canonical/URI search parameters)
 
 FHIR search parsing lives outside this package; callers pass prepared `SearchIndexEntry` values on writes.
 

pkg/postgres/doc.go

@@ -147,6 +147,7 @@
 //   - date.<name>                      → hai_search_date
 //   - number.<name>                    → hai_search_number
 //   - reference.<name> or ref.<name>   → hai_search_reference
+//   - uri.<name>                       → hai_search_string
 //
 // Keys without a prefix default to hai_search_string. QueryPrepared supports the "by-field"
 // plan (args: key, value). AnalyticsStore QueryPrepared supports "by-name-since"

pkg/postgres/search_store.go

@@ -56,6 +56,8 @@ func parseSearchFieldKey(key string) (searchTable, string, error) {
 		return searchTableComposite, parts[1], nil
 	case "text":
 		return searchTableText, parts[1], nil
+	case "uri":
+		return searchTableString, parts[1], nil
 	default:
 		return searchTableString, key, nil
 	}
@@ -193,6 +195,18 @@ func (s *SearchStore) LookupMatch(ctx context.Context, match store.SearchMatch)
 			  AND (value LIKE $4 || '/%%' OR value LIKE $4 || '|%%')
 			ORDER BY resource_id`, table)
 		args = []any{s.tenantID, match.ResourceType, fieldKey, match.Value}
+	case (table == searchTableString) && op == "below":
+		query = fmt.Sprintf(`
+			SELECT resource_id FROM %s
+			WHERE tenant_id = $1 AND resource_type = $2 AND field_key = $3 AND value LIKE $4 || '%%'
+			ORDER BY resource_id`, table)
+		args = []any{s.tenantID, match.ResourceType, fieldKey, match.Value}
+	case (table == searchTableString) && op == "above":
+		query = fmt.Sprintf(`
+			SELECT resource_id FROM %s
+			WHERE tenant_id = $1 AND resource_type = $2 AND field_key = $3 AND $4 LIKE value || '%%'
+			ORDER BY resource_id`, table)
+		args = []any{s.tenantID, match.ResourceType, fieldKey, match.Value}
 	case (table == searchTableDate || table == searchTableNumber) && isComparator(op):
 		sqlOp, err := comparatorSQL(op)
 		if err != nil {

pkg/runtime/README.md

@@ -197,7 +197,7 @@ Build failures roll back partially opened resources before returning an error.
 | SQLite | Embedded/basic search via local `SearchStore` executor |
 | Postgres | Full search service + background reindex worker |
 
-Advanced FHIR search features (`_include`, chained search, composites, FTS) remain **Postgres-first** per `pkg/search`. SQLite persists index rows and supports basic lookups.
+Advanced FHIR search features (`_include` wildcards, `_has`, two-hop chains, uri, composites, FTS) remain **Postgres-first** per `pkg/search`. SQLite persists index rows and supports basic lookups.
 
 ## Sync by mode
 

pkg/search/README.md

@@ -136,10 +136,11 @@ Postgres-first advanced FHIR search:
 | Registry-backed parameters | All installed SearchParameters for enabled resource types |
 | `_count` / `_offset` | Paging with max `_count` of 100 |
 | `_sort` | Registry-backed fields plus `_id` and `_lastUpdated` |
-| Modifiers | `string:exact`, `string:contains`; token/reference modifiers per type |
+| Modifiers | `string:exact`, `string:contains`; `uri:below`, `uri:above`; token/reference modifiers per type |
 | Prefixes | Date/number comparators: `eq`, `ne`, `gt`, `ge`, `lt`, `le`, `sa`, `eb`, `ap` |
-| Chained search | Single-hop only (e.g. `subject.name`) |
-| `_include` / `_revinclude` | Direct includes; wildcards deferred |
+| Chained search | Up to two hops (e.g. `subject.name`, `subject.organization.name`) |
+| Reverse chaining | `_has:Type:ref:param` (one extra nested `_has`) |
+| `_include` / `_revinclude` | Direct includes plus `ResourceType:*` and `*:*` wildcards |
 | Composite search | Declared composite SearchParameters from registry |
 | `_summary` / `_elements` | Response projection at assembly time |
 | Full text | Postgres native FTS via indexed text documents |
@@ -153,7 +154,7 @@ Unsupported semantics return explicit errors (`ErrUnsupportedFeature`, `ErrInval
 - Comma-separated values **OR** within one occurrence (`?name=Smith,Jones`)
 - `_count` and `_offset` apply to primary matches only (not included resources)
 - `_sort` uses registry metadata; tiebreak on resource id
-- Chain depth limited to 1; wildcard includes and recursive includes are rejected
+- Chain depth is limited to 2 hops; `_include:iterate` remains unsupported
 
 ## Index field keys
 
@@ -165,6 +166,7 @@ Unsupported semantics return explicit errors (`ErrUnsupportedFeature`, `ErrInval
 | `string.*` | `string.family` | Normalized strings |
 | `date.*` | `date.birthdate` | Comparable date strings |
 | `reference.*` | `reference.patient` | Reference targets (typed/id/canonical forms) |
+| `uri.*` | `uri.url` | Canonical/URI strings (stored with string indexes) |
 | `composite.*` | `composite.context-type-value` | Composite component values |
 | `text.*` | `text.document` | Postgres full-text document |
 
@@ -209,7 +211,7 @@ url.Values  →  ParseQuery  →  ResolveQuery  →  BuildPlan  →  StoreExecut
 ## Current limits
 
 - Postgres is the primary complete execution backend; SQLite stores indexes and supports basic lookups but not advanced execution
-- Chain depth is limited to 1; wildcard/recursive includes are deferred
+- Chain depth is limited to 2; recursive `_include:iterate` is deferred
 - OpenSearch adapter seam is preserved via `SearchAdvancedExecutor`; not implemented yet
 - No HTTP `_search` endpoint in this package
 - Custom SearchParameters become searchable after snapshot rebuild and reindex completion

pkg/search/doc.go

@@ -18,8 +18,10 @@
 //
 // Postgres-first execution supports:
 //
-//   - _include and _revinclude (direct, non-wildcard)
-//   - single-hop chained search (e.g. subject.name)
+//   - _include and _revinclude, including ResourceType:* and *:* wildcards
+//   - chained search up to two hops (e.g. subject.name, subject.organization.name)
+//   - reverse chaining via _has:Type:ref:param
+//   - uri SearchParameters with :below / :above
 //   - composite SearchParameters from the registry
 //   - modifiers (:exact, :contains on string; date/number prefixes)
 //   - _sort on registry-backed parameters plus _id / _lastUpdated
@@ -33,7 +35,7 @@
 //
 // RegistryIndexer evaluates each installed SearchParameter expression with pkg/fhirpath,
 // normalizes extracted values into typed field keys (token.*, string.*, date.*,
-// reference.*, composite.*, text.*), and emits store.SearchIndexEntry rows consumed
+// reference.*, uri.*, composite.*, text.*), and emits store.SearchIndexEntry rows consumed
 // by store.SearchStore.
 //
 // # Query semantics