在PostgreSQL版本9.1中，我有两个表：ICD9和Dx。我现在希望通过将现有记录更改为不同的键值（在cdesc中）来更新父表ICD9。
如果ICD9表中不存在新密钥（cicd9，cdesc），则新值将级联到子表，Dx :-)
但是，如果ICD9表中已存在具有新值cdesc的“new”键，则由于
而未更新记录错误23505：重复键值违反了唯一约束“constraint_cdesc”。
我需要做的是更新父表ICD9，将旧记录更新为新值，并将此更新级联到DX中使用旧密钥然后删除现有的所有子记录来自ICD9表的未使用的“旧”记录。
对这位新手的任何帮助都会非常感激。 TIA
CREATE TABLE icd9
(
cicd9 character varying(8),
cdesc character varying(80) NOT NULL,
CONSTRAINT constraint_cdesc UNIQUE (cicd9, cdesc),
CONSTRAINT desccheck CHECK (cdesc::text <> ''::text)
)
CREATE TABLE dx
(
cicd9 character varying(8),
cdesc character varying(80) NOT NULL,
CONSTRAINT fk_icd9 FOREIGN KEY (cicd9, cdesc)
REFERENCES icd9 (cicd9, cdesc) MATCH SIMPLE
ON UPDATE CASCADE ON DELETE RESTRICT DEFERRABLE INITIALLY DEFERRED
)
编辑＃1：我想我简化了这些表格结构以便澄清我的观点，这里是完整的结构。非常感谢任何帮助。
CREATE TABLE dx
(
recid serial NOT NULL,
cpatient character varying(33) NOT NULL,
cicd9 character varying(8),
cdesc character varying(80) NOT NULL,
tposted timestamp without time zone NOT NULL,
"timestamp" timestamp without time zone DEFAULT now(),
modified timestamp without time zone DEFAULT now(),
resolved boolean DEFAULT false,
treated boolean DEFAULT false,
chronic boolean DEFAULT false,
groupid character varying(33) NOT NULL,
service integer DEFAULT 0,
pmh boolean DEFAULT false,
explanation text,
CONSTRAINT pk_dx_recid PRIMARY KEY (recid),
CONSTRAINT dx_cpatient_fkey FOREIGN KEY (cpatient)
REFERENCES patients (cpatient) MATCH SIMPLE
ON UPDATE CASCADE ON DELETE RESTRICT,
CONSTRAINT dx_groupid_fkey FOREIGN KEY (groupid)
REFERENCES charts (groupid) MATCH SIMPLE
ON UPDATE CASCADE ON DELETE RESTRICT,
CONSTRAINT fk_icd9 FOREIGN KEY (cicd9, cdesc)
REFERENCES icd9 (cicd9, cdesc) MATCH SIMPLE
ON UPDATE CASCADE ON DELETE RESTRICT DEFERRABLE INITIALLY DEFERRED,
CONSTRAINT noduplicate_dx UNIQUE (cicd9, cdesc, groupid, tposted),
CONSTRAINT desccheck CHECK (cdesc::text <> ''::text),
CONSTRAINT groupcheck CHECK (groupid::bpchar <> ''::bpchar),
CONSTRAINT patientcheck CHECK (cpatient::bpchar <> ''::bpchar)
)
WITH (
OIDS=FALSE
);
ALTER TABLE dx
OWNER TO postgres;
CREATE TABLE icd9
(
recid serial NOT NULL,
cicd9 character varying(8),
cdesc character varying(80) NOT NULL,
"timestamp" timestamp without time zone DEFAULT now(),
modified timestamp without time zone DEFAULT now(),
chronic boolean NOT NULL DEFAULT false,
common boolean NOT NULL DEFAULT false,
CONSTRAINT pk_icd9_recid PRIMARY KEY (recid),
CONSTRAINT constraint_cdesc UNIQUE (cicd9, cdesc),
CONSTRAINT desccheck CHECK (cdesc::text <> ''::text)
)
WITH (
OIDS=FALSE
);
ALTER TABLE icd9
OWNER TO postgres;
答案 0 :(得分：0)
除了表格设计中可能存在的错误之外，我无法暂时暂停将“记录”的键值更新为另一条记录所持有的值所产生的“unique_violation”。在上面的设计中，ICD9文件旨在作为一个库，其中记录可能会也可能不会在系统的其他地方使用。
此问题的解决方案是从引用库的表中移动子记录，然后删除会导致冲突的记录。这些代码大部分来自Finding Foreign Keys with No Indexes，特别感谢@Patrick提供了我需要的最终密钥。以下是执行此工作的代码（适用于我）。希望它对某人有所帮助。
CREATE OR REPLACE FUNCTION g_saveicd9(ocicd9 text, ocdesc text, ncicd9 text, ncdesc text, nchronic boolean, ncommon boolean)
RETURNS void AS
$BODY$
DECLARE
-- Declare row format
o ICD9%rowtype;
n ICD9%rowtype;
BEGIN
-- Existing key values
o.cicd9 := ocicd9;
o.cdesc := ocdesc;
-- New record values
n.cicd9 := ncicd9;
n.cdesc := ncdesc;
n.chronic := nchronic;
n.common := ncommon;
-- Must set contraints all immediate to trigger constraints immediately for exceptions.
SET CONSTRAINTS ALL IMMEDIATE;
BEGIN
-- Edit ICD9 record.
UPDATE icd9 SET
cicd9 = n.cicd9, cdesc = n.cdesc, chronic = n.chronic, common = n.common
WHERE
cicd9 = o.cicd9 and cdesc = o.cdesc;
IF FOUND THEN
-- Successfully changed an existing record to new values. (The new value did not already exist). Exit function.
RETURN;
END IF;
EXCEPTION
WHEN unique_violation THEN
-- The new key already exists, so need to manually move all children to the "new" key.
PERFORM merge_children_of_icd9(o.cicd9, o.cdesc, n.cicd9, n.cdesc);
-- Remove the old key values from ICD9
DELETE FROM icd9
WHERE cicd9 = o.cicd9 and cdesc = o.cdesc;
-- Update existing record.
UPDATE icd9 SET
chronic = n.chronic, common = n.common
WHERE
cicd9 = n.cicd9 and cdesc = n.cdesc;
RETURN; -- Exit function.
END;
-- No record found to update, so create new record.
BEGIN
INSERT INTO icd9(
cicd9, cdesc, chronic, common)
VALUES (
n.cicd9, n.cdesc, n.chronic, n.common);
-- Successfully inserted a new icd9 record, so exit function. This line is not reached if INSERT throws an exception.
RETURN;
EXCEPTION
WHEN unique_violation THEN
-- Key (o.cicd9,o.cdesc) not found for update, but target key (n.cicd9,n.cdesc) already exists.
-- Update target record with non-key values.
UPDATE icd9 SET
chronic = n.chronic, common = n.common
WHERE
cicd9 = n.cicd9 and cdesc = n.cdesc;
RETURN;
END;
END;
$BODY$
LANGUAGE plpgsql VOLATILE
COST 100;
ALTER FUNCTION g_saveicd9(text, text, text, text, boolean, boolean)
OWNER TO postgres;
CREATE OR REPLACE FUNCTION merge_children_of_icd9(ocicd9 text, ocdesc text, ncicd9 text, ncdesc text)
RETURNS void AS
$BODY$
DECLARE
r RECORD;
BEGIN
FOR r IN
WITH fk_actions ( code, action ) AS (
VALUES ( 'a', 'error' ),
( 'r', 'restrict' ),
( 'c', 'cascade' ),
( 'n', 'set null' ),
( 'd', 'set default' )
),
fk_list AS (
SELECT pg_constraint.oid as fkoid, conrelid, confrelid::regclass as parentid,
conname, relname, nspname,
fk_actions_update.action as update_action,
fk_actions_delete.action as delete_action,
conkey as key_cols
FROM pg_constraint
JOIN pg_class ON conrelid = pg_class.oid
JOIN pg_namespace ON pg_class.relnamespace = pg_namespace.oid
JOIN fk_actions AS fk_actions_update ON confupdtype = fk_actions_update.code
JOIN fk_actions AS fk_actions_delete ON confdeltype = fk_actions_delete.code
WHERE contype = 'f'
),
fk_attributes AS (
SELECT fkoid, conrelid, attname, attnum
FROM fk_list
JOIN pg_attribute
ON conrelid = attrelid
AND attnum = ANY( key_cols )
ORDER BY fkoid, attnum
),
fk_cols_list AS (
SELECT fkoid, array_agg(attname) as cols_list
FROM fk_attributes
GROUP BY fkoid
)
SELECT fk_list.fkoid, fk_list.conrelid, fk_list.parentid, fk_list.conname, fk_list.relname, fk_cols_list.cols_list
FROM fk_list
JOIN fk_cols_list USING (fkoid)
WHERE parentid = 'icd9'::regclass
LOOP
-- In an UPDATE statement in PL/pgSQL, the table name has to be given as a literal. If you want to dynamically set the
-- table name and the columns, use the EXECUTE command and paste the query string together.
-- The USING clause can only be used for substituting data values.
-- cols_list[1] is cicd9. cols_list[2] is cdesc.
EXECUTE 'UPDATE ' || quote_ident(r.relname) ||
' SET ' || quote_ident(r.cols_list[1]) || ' = $1, '
|| quote_ident(r.cols_list[2]) || ' = $2' ||
' WHERE ' || quote_ident(r.cols_list[1]) || ' = $3 AND '
|| quote_ident(r.cols_list[2]) || ' = $4'
USING ncicd9, ncdesc, ocicd9, ocdesc;
END LOOP;
RETURN;
END
$BODY$
LANGUAGE plpgsql VOLATILE
COST 100;
ALTER FUNCTION merge_children_of_icd9(text, text, text, text)
OWNER TO postgres;