Module schema 

Table and column layout for the PG search backend.

Where a parameter is stored depends on whether it can repeat:

• Singular: a scalar column on its resource type’s table (r4_patient_idx). Scalars support ordered comparisons, prefix matches, sorts and composite indexes; arrays only support overlap.
• Repeating: one row per value in the shared table for its type (r4_param_token_idx, …), keyed by canonical URL. Same indexes, at the cost of a join.

Every table references its resource by res_key, a BIGINT allocated by the anchor (r4_resource_idx). Only the anchor stores tenant, project, type and id, which keeps the other indexes small.

Cardinality is precomputed in crate::search_parameter_cardinality. Anything not known to be singular goes to the shared tables, since a scalar column would silently drop extra values.

Structs

ColumnDef

One generated column.

ResourceTypeSchema

One resource type’s table of singular parameters.

SchemaRegistry

Every generated table layout for one FHIR version.

SharedColumn

A value column of a SharedTable. Shared by the DDL and the batch insert.

Enums

ColumnType

A generated column’s type. Always scalar: repeating values live in rows.

IndexKind

How a column is indexed.

ParamColumns

The columns backing one parameter. Multi-part values keep their parts on the same row, so e.g. a token’s system stays paired with its code.

SharedTable

The shared table for one value type, holding repeating parameters.

Constants

SHARED_TABLES

Every shared table, in creation order.

STRING_PREFIX_CHARS

How many leading characters of a string value its prefix B-tree covers.

Functions

column_index

Position of name in schema.columns (sorted, so binary search).

column_names

Every column a parameter occupies, in insert order.

generate_schemas

Builds every resource type table from the singular system parameters, plus the anchor’s columns for the resource-level ones.

resource_table_name

r4_resource_idx: the anchor, one row per indexed resource.

resource_type_to_table

r4_patient_idx: one table per resource type.

shared_table_for

The shared table for a parameter type; None for composite and special.

shared_table_kind

The value type a shared table holds.

shared_table_name

r4_param_token_idx. The param_ segment can’t clash with a type table, since no resource type name contains an underscore.

shared_value_columns

A shared table’s value columns, after the res_key, param_identity keys. The DDL and the inserts both read this list, so they cannot drift.

sql_type

SQL type for CREATE TABLE / ADD COLUMN.

string_prefix_expr

The indexed expression over a string column. Prefix and exact searches compare it, so the planner can match them to the index.