Need to populate table with Foreign and Primary key - oracle

Question

I need to create three tables from all_tab_col system table such that schema details are in one schema_detail table, table details are in table_detail table and column details are in col_table. These three tables are to be populated simultaneously through a stored procedure, with PK(generated using SEQUENCE) in schema_detail is FK in table_detail table and PK(generated using SEQUENCE) in table_detail is FK in col_detail table.

Answer 1

SQL is a set based language, so I would be tempted to solve your task with three set bases steps.
Some mock up tables (just add columns for the details you are interested in):
CREATE TABLE schema_detail (
schema_id NUMBER GENERATED ALWAYS AS IDENTITY NOT NULL,
schema_name VARCHAR2(128 BYTE) NOT NULL,
CONSTRAINT schema_detail_pk PRIMARY KEY (schema_id)
);
CREATE TABLE table_detail (
schema_id NUMBER,
table_id NUMBER GENERATED ALWAYS AS IDENTITY NOT NULL,
table_name VARCHAR2(128 BYTE) NOT NULL,
CONSTRAINT table_detail_pk PRIMARY KEY (table_id),
CONSTRAINT table_detail_fk FOREIGN KEY (schema_id)
REFERENCES schema_detail(schema_id)
ON DELETE CASCADE
);
CREATE INDEX table_detail_schema_idx ON table_detail(schema_id);
CREATE INDEX table_detail_name_idx ON table_detail(table_name);
CREATE TABLE col_detail (
table_id NUMBER,
col_id NUMBER GENERATED ALWAYS AS IDENTITY NOT NULL,
col_name VARCHAR2(128 BYTE) NOT NULL,
CONSTRAINT col_detail_pk PRIMARY KEY (col_id),
CONSTRAINT col_detail_fk FOREIGN KEY (table_id)
REFERENCES table_detail(table_id)
ON DELETE CASCADE
);
CREATE INDEX col_detail ON col_detail(table_id);
I'd fill the table schema_detail first. PK is generated automatically:
INSERT INTO schema_detail(schema_name)
SELECT DISTINCT c.owner FROM all_tab_columns c ORDER BY owner;
SCHEMA_ID SCHEMA_NAME
1 APPQOSSYS
2 AUDSYS
3 CTXSYS
...
Next, I'd fill the tables. The schema_id needs to be looked up the the schema_detail table. Again, we let the PKs be generated automatically:
INSERT INTO table_detail(schema_id, table_name)
SELECT DISTINCT s.schema_id, c.table_name
FROM all_tab_columns c
JOIN schema_detail s ON c.owner = s.schema_name
ORDER BY table_name;
SCHEMA_ID TABLE_ID TABLE_NAME
1 8403 WLM_CLASSIFIER_PLAN
1 8404 WLM_FEATURE_USAGE
1 8405 WLM_METRICS_STREAM
...
And last, I'd fill the columns:
INSERT INTO col_detail(table_id, col_name)
SELECT DISTINCT t.table_id, c.column_name
FROM all_tab_columns c
JOIN table_detail t ON c.table_name = t.table_name
JOIN schema_detail s ON c.owner = s.schema_name
ORDER BY s.schema_id, t.table_id, c.column_name;
Does this solve your question or do you need a PL/SQL procedure?

Answer 2

In case you insist on a PL/SQL stored procedure, I would code it along the lines of:
CREATE OR REPLACE PROCEDURE myproc IS
schema_id schema_detail.schema_id%type;
table_id table_detail.table_id%type;
FUNCTION lookup_insert_schema (p_schema_name VARCHAR2)
RETURN NUMBER
IS
sid schema_detail.schema_id%type;
BEGIN
BEGIN
SELECT schema_id INTO sid
FROM schema_detail
WHERE schema_name = p_schema_name;
EXCEPTION WHEN NO_DATA_FOUND THEN
INSERT INTO schema_detail (schema_name)
VALUES (p_schema_name)
RETURNING schema_id INTO sid;
END;
RETURN sid;
END lookup_insert_schema;
-- lookup p_table_name in table table_detail, if not found, insert it
FUNCTION lookup_insert_table (p_schema_id NUMBER, p_table_name VARCHAR)
RETURN NUMBER
IS
tid table_detail.table_id%type;
BEGIN
BEGIN
SELECT table_id INTO tid
FROM table_detail
WHERE schema_id = p_schema_id
AND table_name = p_table_name;
EXCEPTION WHEN NO_DATA_FOUND THEN
INSERT INTO table_detail (schema_id, table_name)
VALUES (p_schema_id, p_table_name)
RETURNING table_id INTO tid;
END;
RETURN tid;
END lookup_insert_table;
BEGIN
FOR r IN (SELECT * FROM all_tab_columns)
LOOP
schema_id := lookup_insert_schema(r.owner);
table_id := lookup_insert_table(schema_id, r.table_name);
INSERT INTO col_detail (table_id, col_name)
VALUES (table_id, r.column_name);
END LOOP;
END myproc;
/