Oracle Advanced Dml
- 1. Oracle Advanced DML Alan Beaulieu Beaulieu Consulting July 2008
- 2. Agenda What is Advanced DML? Conditional Inserts Multi-table Inserts Upserts (Update/Insert) Updating via Joins
- 3. What is Advanced DML? Non-standard ways to insert, update, delete Includes variations on existing statements along with new statements Reduces need for procedural code (i.e. PL/SQL) Especially pertinent to data-warehouse environments
- 4. Inserts New (since 9i) variations allow you to: Insert rows into one of several tables Insert rows into multiple tables Insert different flavors of the same row multiple times
- 5. Insert First Allows each row to be placed into one of several tables using conditional logic. Example: Insert into either current or history table depending on date INSERT FIRST WHEN cal_dt = trunc(sysdate) THEN INTO pos_sum_dly VALUES (fund_id, cal_dt, security_id, …) WHEN cal_dt < trunc(sysdate) THEN INTO pos_sum_dly_hist VALUES (fund_id, cal_dt, security_id, …) SELECT fund_id, cal_dt, asset_id security_id, … FROM cus_pos_extrnl Insert today’s data into pos_sum_dly Insert old data into pos_sum_dly_hist
- 6. Insert All Allows each row to be placed into 0, 1, …N tables using conditional logic. Example: Insert data into pos_sum_dly, along with optional warnings INSERT ALL WHEN mtrty_dt IS NULL THEN INTO di_exception_rpt VALUES ( 'INFO:INVALID RSM_MATURITY_DATE in CUSPOS' , …) WHEN 1 = 1 THEN INTO pos_sum_dly VALUES (fund_id, cal_dt, security_id, …) SELECT fund_id, cal_dt, asset_id security_id, … FROM cus_pos_extrnl Insert warning record if maturity date is NULL Always insert into pos_sum_dly
- 7. Insert All (cntd) Allows different flavors of each row to be inserted into the same table. Example: Add pricing data going out 7 days INSERT ALL INTO pricing_master VALUES (sec_id, src_cd, prc_typ_cd, crncy_cd, effect_dt, …) INTO pricing_master VALUES (sec_id, src_cd, prc_typ_cd, crncy_cd, effect_dt + 1, …) … INTO pricing_master VALUES (sec_id, src_cd, prc_typ_cd, crncy_cd, effect_dt + 6, …) SELECT sec_id, src_cd, prc_typ_cd, crncy_cd, effect_dt, … FROM pricing_extrnl
- 8. INSERT/UPDATE Pre-9i implementation of INSERT/UPDATE logic… BEGIN INSERT INTO table_x (a, b, c, …) VALUES (v_1, v_2, v_3, …); EXCEPTION WHEN DUP_VAL_ON_INDEX UPDATE table_x SET b = v_2, c = v_3 WHERE a = v_1; END;
- 9. INSERT/UPDATE (cntd) New (9i) SQL command : MERGE Allows you to both update and insert with a single statement If a row already exists, data is updated; otherwise, data is inserted Also includes the ability to do conditional DELETE’s
- 10. Merge Allows data to be either updated or inserted using a single SQL statement. Example: MERGE INTO pos_sum_dly trg USING (SELECT fund_id, cal_dt, asset_id security_id, … FROM cus_pos_extrnl) src ON (trg.fund_id = src.fund_id, trg.cal_dt = src.cal_dt, …) WHEN MATCHED THEN UPDATE SET trg.mtrty_dt = src.pos_mtrty_dt, … WHEN NOT MATCHED THEN INSERT VALUES (src.fund_id, src.cal_dt, src.security_id, …) Row exists - Update No row exists - Insert
- 11. Merge (cntd) Don’t need to specify both WHEN MATCHED and WHEN NOT MATCHED Example: Fill in values for denormalized column MERGE /*+ PARALLEL(trg, 8) */ INTO income_recv_asof trg USING (SELECT /*+ FULL(ira) PARALLEL(ira, 8) USE_NL_WITH_INDEX(iraf, income_recv_asof_fin_key) */ ira.ssb_fund, ira.period_indicator, ira.income_instance, ira.asof_date, iraf.fin_currency FROM income_recv_asof ira, income_recv_asof_fin iraf WHERE ira.ssb_fund = iraf.ssb_fund AND ira.period_indicator = iraf.period_indicator AND ira.income_instance = iraf.income_instance AND ira.asof_date = iraf.asof_date AND ira.income_currency <> iraf.fin_currency ) src ON (src.ssb_fund = trg.ssb_fund AND src.period_indicator = trg.period_indicator AND src.income_instance = trg.income_instance AND src.asof_date = trg.asof_date) WHEN MATCHED THEN UPDATE SET trg.income_currency = src.fin_currency; Same table being updated…
- 12. Updating Using Joins SQL Server lets you do the following: UPDATE Sales.SalesPerson SET SalesYTD = SalesYTD + SubTotal FROM Sales.SalesPerson AS sp JOIN Sales.SalesOrderHeader AS so ON sp.SalesPersonID = so.SalesPersonID AND so.OrderDate = (SELECT MAX(OrderDate) FROM Sales.SalesOrderHeader WHERE SalesPersonID = sp.SalesPersonID);
- 13. Updating Using Joins (cntd) Doesn’t work with Oracle unless you update through an inline view: UPDATE (SELECT hdr.fund_type, dhr.fund_type new_typ FROM fund_header hdr INNER JOIN dhr_t dhr ON dhr.ssb_fund = hdr.ssb_fund ) SET fund_type = new_typ;
- 14. Updating Using Joins (cntd) However, opposite statement doesn’t work: UPDATE (SELECT dhr.fund_type, hdr.fund_type new_typ FROM dhr_t dhr INNER JOIN fund_header hdr ON dhr.ssb_fund = hdr.ssb_fund AND hdr.eval_ind = '0' ) SET fund_type = new_typ; Error at line 1 ORA-01779: cannot modify a column which maps to a non key-preserved table
- 15. Deleting Using Joins Again, only through an inline view: DELETE (SELECT hdr.ssb_fund FROM fund_header hdr INNER JOIN dhr_t dhr ON dhr.ssb_fund = hdr.ssb_fund WHERE hdr.tot_mkt_value < 1 AND dhr.max_bal < 100 ); Does it matter which columns are selected?