From 1250e797afd9a206a1dc579601429c2af91de388 Mon Sep 17 00:00:00 2001
From: tetragon <tetragon@4979c152-3d1c-0410-bac9-87ea11338e46>
Date: Fri, 28 Dec 2007 02:40:43 +0000
Subject: Adding a fix script for the primary key to the tax table

git-svn-id: https://ledger-smb.svn.sourceforge.net/svnroot/ledger-smb/branches/1.2@2011 4979c152-3d1c-0410-bac9-87ea11338e46
---
 sql/fixes/tax_pkey_duplicate.sql | 13 +++++++++++++
 1 file changed, 13 insertions(+)
 create mode 100644 sql/fixes/tax_pkey_duplicate.sql

diff --git a/sql/fixes/tax_pkey_duplicate.sql b/sql/fixes/tax_pkey_duplicate.sql
new file mode 100644
index 00000000..f590d8ca
--- /dev/null
+++ b/sql/fixes/tax_pkey_duplicate.sql
@@ -0,0 +1,13 @@
+-- SC: Replaces the primary key of the tax table with a check for if the
+--     combination of chart_id and validto is unique.  An index is added to
+--     check for the case of multiple NULL validto values and fail if that would
+--     result.
+
+ALTER TABLE tax DROP CONSTRAINT tax_pkey;
+ALTER TABLE tax ADD CONSTRAINT tax_unique UNIQUE (chart_id, validto);
+COMMENT ON CONSTRAINT tax_unique ON tax IS
+$$Checks on the base uniqueness of the chart_id, validto combination$$;
+
+CREATE UNIQUE INDEX tax_null_validto_unique_idx ON tax(chart_id) WHERE validto IS NULL;
+COMMENT ON INDEX tax_null_validto_unique_idx ON tax IS
+$$Part of primary key emulation for the tax table, ensures at most one NULL validto for each chart_id$$;
-- 
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