# duckdb/bridge.sql

bridge.sql — DROP legacy bare view (migration guard); CREATE _act and _hst.

bridge.sql — DROP legacy bare view (migration guard); CREATE _act and _hst.

## Context fields

- `.BridgeCols`
- `.BridgeSchema`
- `.BridgeTable`
- `.HistorySchema`
- `.HistoryTable`

## Template

```sql
{{- /* bridge.sql — DROP legacy bare view (migration guard); CREATE _act and _hst.
     All history tables have the universal column set (DESIGN-012), so bridge views
     always use the same SCD2-style projection regardless of history mode. */ -}}
DROP VIEW IF EXISTS "{{ .BridgeSchema }}"."{{ .BridgeTable }}";
DROP VIEW IF EXISTS "{{ .BridgeSchema }}"."{{ .BridgeTable }}_act";
DROP VIEW IF EXISTS "{{ .BridgeSchema }}"."{{ .BridgeTable }}_hst";

CREATE OR REPLACE VIEW "{{ .BridgeSchema }}"."{{ .BridgeTable }}_act" AS
SELECT
{{- $first := true }}
{{- range $i, $col := .BridgeCols }}
{{- if $col.Include }}
{{- if $first }}
    {{ $col.ProjectionExpr }}{{ if $col.HasAlias }} AS {{ $col.TargetName }}{{ end }}
{{- $first = false }}
{{- else }}
    ,{{ $col.ProjectionExpr }}{{ if $col.HasAlias }} AS {{ $col.TargetName }}{{ end }}
{{- end }}
{{- end }}
{{- end }}
    ,amf_run_id
    ,amf_valid_from
    ,amf_updated_at
FROM "{{ .HistorySchema }}"."{{ .HistoryTable }}"
WHERE amf_valid_to IS NULL;

CREATE OR REPLACE VIEW "{{ .BridgeSchema }}"."{{ .BridgeTable }}_hst" AS
SELECT
{{- $first2 := true }}
{{- range $i, $col := .BridgeCols }}
{{- if $col.Include }}
{{- if $first2 }}
    {{ $col.ProjectionExpr }}{{ if $col.HasAlias }} AS {{ $col.TargetName }}{{ end }}
{{- $first2 = false }}
{{- else }}
    ,{{ $col.ProjectionExpr }}{{ if $col.HasAlias }} AS {{ $col.TargetName }}{{ end }}
{{- end }}
{{- end }}
{{- end }}
    ,amf_run_id
    ,amf_valid_from
    ,amf_valid_to
    ,amf_updated_at
FROM "{{ .HistorySchema }}"."{{ .HistoryTable }}"
```

## Provenance

| | |
| --- | --- |
| Platform | `duckdb` |
| File | `duckdb/bridge.sql` |
| Version | `v1.3.1` |
| Lines | 44 |
| SHA-256 | `2b8764a9b4e3cf9f1f96ccc0e28c3cc27b959ef28c8f732904d85bab605ed80c` |