Hein
d84306934a
Existing databases that already ran an old migration kept stale NOT NULL constraints and mismatched column types/defaults, because the schema writer only emitted idempotent ADD COLUMN IF NOT EXISTS guards and never altered columns that already existed. - Emit guarded ALTER COLUMN ... SET/DROP NOT NULL when a column's nullability differs from the model. - Emit guarded ALTER COLUMN ... TYPE, falling back to renaming the old column and adding a fresh one when the in-place conversion fails. - Emit guarded ALTER COLUMN ... SET/DROP DEFAULT for default drift. - Collapse the previously duplicated plain/guarded templates so WriteSchema (full-schema, live-state-checking) and WriteMigration (diff-based) share the same guarded SQL templates and Go helpers instead of maintaining the logic twice.
30 lines
894 B
Cheetah
30 lines
894 B
Cheetah
DO $$
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DECLARE
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current_default text;
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BEGIN
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SELECT pg_catalog.pg_get_expr(d.adbin, d.adrelid)
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INTO current_default
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FROM pg_attribute a
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JOIN pg_class t ON t.oid = a.attrelid
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JOIN pg_namespace n ON n.oid = t.relnamespace
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LEFT JOIN pg_attrdef d ON d.adrelid = a.attrelid AND d.adnum = a.attnum
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WHERE n.nspname = '{{.SchemaName}}'
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AND t.relname = '{{.TableName}}'
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AND a.attname = '{{.ColumnName}}'
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AND a.attnum > 0
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AND NOT a.attisdropped;
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{{- if .SetDefault }}
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IF current_default IS DISTINCT FROM {{quote .DefaultValue}} THEN
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ALTER TABLE {{qual_table .SchemaName .TableName}}
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ALTER COLUMN {{quote_ident .ColumnName}} SET DEFAULT {{.DefaultValue}};
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END IF;
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{{- else }}
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IF current_default IS NOT NULL THEN
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ALTER TABLE {{qual_table .SchemaName .TableName}}
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ALTER COLUMN {{quote_ident .ColumnName}} DROP DEFAULT;
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END IF;
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{{- end }}
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END;
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$$;
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