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1 NOTE itty bitty fonts in this presentation SQL> exec sample_font Can you read this? 1

2 2

3 Connor McDonald OracleDBA co.uk 3

4 4

5 5 about me

6 same old crap about years of experience flog the book hook up a consulting gig awards 6

7 this is NOT a best practice talk 7

8 best practice 8

9 best practice 9

10 practice, practice, practice

11 11 what we're doing

12 why SQL favourites Analytics Model clause 12

13 why talk about SQL (part 1) 13

14 14 true story

15 15 SOA project

16 C#, C++ OSB Weblogic Tuxedo 16

17 17

18 18

19 19 huh?

20 DEPT EMP deptadapter = new OracleDataAdapter(); deptadapter.selectcommand = new OracleCommand( "SELECT * FROM DEPT",conn); deptdataset = new DataSet("deptDataSet"); deptadapter.fill( deptdataset, "dept"); empadapter = new OracleDataAdapter(); empadapter.selectcommand = new OracleCommand( "SELECT * FROM EMP",conn); empdataset = new DataSet("empDataSet"); empadapter.fill( empdataset, "emp"); 20

21 21 SQL> select... 2 from DEPT d, 3 EMP e 4 where d.deptno = e.deptno

22 22 "wow"

23 23 SQL is getting simpler

24 Code 1985 Value SQL 24 m/f c/s web soa

25 Code Value SQL 25 m/f c/s web soa

26 26

27 27

28 "Its purpose is to relieve the developer from a significant portion of relational data persistence-related programming tasks." 28

29 29

30 30

32 why talk about SQL (part 2) 32

33 we suck at relational......technically 33

34 34 not our fault

35 35 Codd & Date

36 36 "data is represented as mathematical n-ary relations, an n-ary relation being a subset of the Cartesian product of n domains."

37 37 huh?

38 we excel at relational......in the real world 38

39 39 shopping

40 40 in the real world

41 efficient drive to shop; pick up items; pay for items; drive home; maybe fill up with petrol; maybe pick up a newspaper; value add 41

42 42 in the technical world

43 Shopping v1.0 subroutine PURCHASE_ITEM(item_id) - drive to shop - obtain item - pay for item - drive home Shopping v2.0 for each_item in LIST_OF_ITEMS do purchase_item; end loop; ORA-20000: No petrol found at supermarket 43 Shopping v2.1

44 business analysts... procedural analysis 44

45 technical analysts... procedural specifications 45

46 programmers procedural programs 46

47 why talk about SQL (part 3) 47

48 48

49 49

50 50 Warning: gratuitous book plug!!!

51 why talk about SQL (part 4) 51

52 3GL's suck... for database 52

53 53 too much code, too hard

54 ocmd = New OracleCommand("SELECT productname AS ""Product Name"", description AS ""Description""" & _ ", category AS ""Category"", price AS ""Price"" FROM producttab", conn) ocmd.commandtype = CommandType.Text oreader = ocmd.executereader() C# Dim dt As DataTable = New DataTable("producttab") Dim dcolumn As DataColumn Dim i As Integer Dim count As Integer Dim colname As String Dim coltype As System.Type sbox.appendtext("current FetchSize value is " + oreader.fetchsize.tostring() + " bytes " + Environment.NewLine) sbox.update() 'Get the number of columns in this OracleDataReader count = oreader.fieldcount sbox.appendtext("fetching data with given FetchSize.." + Environment.NewLine) sbox.update() 'Add the columns in the DataTable For i = 0 To count - 1 colname = oreader.getname(i) coltype = oreader.getfieldtype(i) dcolumn = New DataColumn(colname, coltype) dt.columns.add(dcolumn) Next 'Make the first column the primary key column. Dim PrimaryKeyColumns(0) As DataColumn PrimaryKeyColumns(0) = dt.columns("productname") dt.primarykey = PrimaryKeyColumns 'Populate the table While oreader.read() Dim drow As DataRow = dt.newrow() drow(oreader.getname(0)) = oreader.getstring(0) drow(oreader.getname(1)) = oreader.getstring(1) drow(oreader.getname(2)) = oreader.getstring(2) drow(oreader.getname(3)) = oreader.getdecimal(3) dt.rows.add(drow) End While 54

55 import java.sql.* import java.math.* import java.io.* import java.awt.* class JdbcTest { public static void main (String args []) throws SQLException { // Load Oracle driver DriverManager.registerDriver (new oracle.jdbc.oracledriver()); Java // Connect to the local database Connection conn = DriverManager.getConnection ("jdbc:oracle:thin:@myhost:1521:orcl", "hr", "password"); // Query the employee names Statement stmt = conn.createstatement (); ResultSet rset = stmt.executequery ("SELECT last_name FROM employees"); // Print the name out while (rset.next ()) System.out.println (rset.getstring (1)); // Close the result set, statement, and the connection rset.close(); stmt.close(); conn.close(); } } 55

56 56 PLSQL the only exception

57 PLSQL Users Guide and Reference line 1 57

58 58 "PL/SQL, Oracle's procedural extension of SQL"

59 59 its all about the SQL

60 60 part 2 my favourites

61 61 subquery factoring

62 62 WITH clause

63 SQL> WITH last_hire AS 2 ( select deptno, max(hiredate) 3 from emp 4 group by deptno 5 ) 6 select * from last_hire; DEPTNO MAX(HIRED DEC JAN JAN-82 63

64 64 "gee...wow"

65 65 why is it cool?

66 66 good solution metaphor

67 "First, get the total salary paid by department... SQL> WITH dept_salaries AS ( 2 SELECT dname, SUM(sal) dept_sal 3 FROM emp e, dept d 4 WHERE e.deptno = d.deptno 5 GROUP BY dname), 67

68 "...then get the average of these totals... 6 avg_sal AS ( SELECT AVG(dept_sal) avsal 7 FROM dept_salaries) 68

69 "...then list those departments above average." 8 SELECT * FROM dept_salaries d, avg_sal a 9 WHERE d.dept_sal > a.avsal 10 ORDER BY d.dname; 69

70 SQL> WITH dept_salaries AS ( 2 SELECT dname, SUM(sal) dept_sal 3 FROM emp e, dept d 4 WHERE e.deptno = d.deptno 5 GROUP BY dname), 6 avg_sal AS ( SELECT AVG(dept_sal) avsal 7 FROM dept_salaries) 8 SELECT * FROM dept_salaries d, avg_sal a 9 WHERE d.dept_sal > a.avsal 10 ORDER BY d.dname; 70

71 71 procedural approach...

72 72...relational solution

73 73 things to note...

74 74 execution plan

75 75 two possibilities

76 76 temporary storage

77 Id Operation Name SELECT STATEMENT 1 TEMP TABLE TRANSFORMATION 2 LOAD AS SELECT 3 HASH GROUP BY 4 MERGE JOIN 5 TABLE ACCESS BY INDEX ROWID DEPT 6 INDEX FULL SCAN PK_DEPT 7 SORT JOIN 8 TABLE ACCESS FULL EMP 9 SORT ORDER BY 10 NESTED LOOPS 11 VIEW 12 SORT AGGREGATE 13 VIEW 14 TABLE ACCESS FULL SYS_TEMP_0FD9D6624_AF422F5 15 VIEW 16 TABLE ACCESS FULL SYS_TEMP_0FD9D6624_AF422F

78 SQL> alter session set sql_trace = true; Session altered. SQL> WITH dept_salaries AS ( 2 SELECT dname, SUM(sal) dept_sal 3 FROM emp e, dept d 4 WHERE e.deptno = d.deptno 5 GROUP BY dname), 6 avg_sal AS ( SELECT AVG(dept_sal) asal 7 FROM dept_salaries) 8 SELECT * FROM dept_salaries d, avg_sal a 9 WHERE d.dept_sal > a.asal 10 ORDER BY d.dname; DNAME DEPT_SAL ASAL RESEARCH SQL> alter session set sql_trace = false; Session altered. 78

79 PARSING IN CURSOR #12 len=179 dep=1 uid=0 oct=1... CREATE GLOBAL TEMPORARY TABLE "SYS"."SYS_TEMP_0FD9D6625_AF422F5" ("C0" VARCHAR2(14),"C1" NUMBER ) IN_MEMORY_METADATA CURSOR_SPECIFIC_SEGMENT STORAGE (OBJNO ) NOPARALLEL END OF STMT 79

80 80 no temporary storage

81 Id Operation Name SELECT STATEMENT 1 SORT ORDER BY 2 NESTED LOOPS 3 VIEW 4 SORT AGGREGATE 5 VIEW 6 HASH GROUP BY 7 MERGE JOIN 8 TABLE ACCESS BY INDEX ROWID DEPT 9 INDEX FULL SCAN PK_DEPT 10 SORT JOIN 11 TABLE ACCESS FULL EMP 12 VIEW 13 SORT GROUP BY 14 MERGE JOIN 15 TABLE ACCESS BY INDEX ROWID DEPT 16 INDEX FULL SCAN PK_DEPT 17 SORT JOIN 18 TABLE ACCESS FULL EMP

82 82 explicit control

83 83 SQL> WITH dept_salaries AS ( 2 SELECT /*+ INLINE */ dname, SUM(sal) dept_sal 3 FROM emp e, dept d 4 WHERE e.deptno = d.deptno 5 GROUP BY dname), 6 avg_sal AS ( SELECT AVG(dept_sal) asal 7 FROM dept_salaries) 8 SELECT * FROM dept_salaries d, avg_sal a 9 WHERE d.dept_sal > a.asal 10 ORDER BY d.dname;

84 84 SQL> WITH dept_salaries AS ( 2 SELECT /*+ MATERIALIZE*/ dname, SUM(sal) dept_sal 3 FROM emp e, dept d 4 WHERE e.deptno = d.deptno 5 GROUP BY dname), 6 avg_sal AS ( SELECT AVG(dept_sal) asal 7 FROM dept_salaries) 8 SELECT * FROM dept_salaries d, avg_sal a 9 WHERE d.dept_sal > a.asal 10 ORDER BY d.dname;

85 85 undocumented... sort of

86 86 useful control over optimizer

87 87 useful control over database links

88 take care within a view metalink bug

89 89 take care in read-only standby

91 91

92 92 more on that shortly...

93 93 favourite ( prep work )

94 94 hierarchy queries

95 SQL> select empno, ename, mgr 2 from emp 3 connect by prior empno = mgr 4 start with mgr is null; EMPNO ENAME MGR KING 7566 JONES SCOTT ADAMS FORD BLAKE WARD MARTIN TURNER JAMES CLARK MILLER

96 SQL> select empno, rpad(' ',level*3) ename ename, mgr 2 from emp 3 connect by prior empno = mgr 4 start with mgr is null; EMPNO ENAME MGR KING 7566 JONES SCOTT ADAMS FORD BLAKE WARD MARTIN TURNER JAMES CLARK MILLER

97 97

98 98 much much more...

99 99 "its too slow"

100 SQL> create table EMP_DUPS 2 as select * 3 from 4 ( select level seq 5 from DUAL 6 connect by level <= 10 ), 7 EMP 8 / Table created. 100

101 SQL> create table EMP_DUPS 2 as select * 3 from 4 ( select level seq 5 from DUAL 6 connect by level <= 10 ), 7 EMP 8 / Table created. 101

102 SQL> select level seq 2 from DUAL 3 connect by level <= 10 4 / SEQ

103 103 any number of rows

104 SQL> select level seq 2 from DUAL 3 connect by level <= 10; Id Operation Name Rows SELECT STATEMENT 1 * 1 CONNECT BY WITHOUT FILTERING 2 FAST DUAL Statistics recursive calls 0 db block gets 0 consistent gets 0 physical reads 104

105 105 "free"

106 106 take care with extremes

107 SQL> select level seq 2 from DUAL 3 connect by level <= ; ERROR at line 1: ORA-04030: out of process memory when... SQL> select name, value 2 from v$statname n, 3 v$sesstat s 4 where n.statistic# = s.statistic# 5 and n.name in ('session uga memory', 6 'session pga memory') 7 and s.sid = 130; NAME VALUE session uga memory session pga memory

select rownum from ( select level from dual connect by level <= 10000 ), ( select level from dual connect

108 select rownum from ( select level from dual connect by level <= ), ( select level from dual connect by level <= ), ( select level from dual connect by level <= ) Acknowledgement: Tanel Poder 108

109 SQL> select count(*) from EMP; COUNT(*) SQL> select count(*) from EMP_DUPS; COUNT(*)

110 110 SQL> select seq, empno, ename, mgr 2 from emp_dups; SEQ EMPNO ENAME MGR KING JONES SCOTT KING JONES SCOTT KING JONES SCOTT rows selected.

111 SQL> select 2 empno, rpad(' ',level*3) ename ename, mgr 3 from emp_dups 4 where seq = 1 5 connect by prior empno = mgr 6 start with mgr is null; EMPNO ENAME MGR KING 7566 JONES SCOTT ADAMS ADAMS ADAMS ADAMS 7788 [snip] 2831 rows selected. 111

112 112 SQL> select DISTINCT 2 empno, rpad(' ',level*3) ename ename, mgr 3 from emp_dups 4 where seq = 1 5 connect by prior empno = mgr 6 start with mgr is null; EMPNO ENAME MGR KING 7788 SCOTT BLAKE WARD CLARK ADAMS TURNER JONES MARTIN MILLER

113 SQL> select empno, rpad(' ',level*3) ename ename, mgr 2 from emp_dups 3 where hire_date seq = 1 > '01-JAN-2009' 4 connect by prior empno = mgr 5 and prior seq = seq 6 start with mgr is null 7 and seq = 1; 113

114 114 "its too slow"

115 115 lots more...

116 SQL> select SYS_CONNECT_BY_PATH(ename,'-') full_tree 2 from emp 3 start with mgr is null 4 connect by prior empno = mgr FULL_TREE KING -KING-BLAKE -KING-BLAKE-JAMES -KING-BLAKE-ALLEN -KING-BLAKE-WARD -KING-CLARK -KING-CLARK-MILLER

117 SQL> select rpad(' ',level) sys_connect_by_path(ename,'-'), 2 empno, dname 3 from emp e, dept d 4 where d.deptno = e.deptno 5 start with mgr is null 6 connect by prior empno = mgr FULL_TREE EMPNO DNAME KING 7839 ACCOUNTING -KING-BLAKE 7698 SALES -KING-BLAKE-JAMES 7499 SALES -KING-BLAKE-ALLEN 7900 SALES -KING-BLAKE-WARD 7521 SALES -KING-CLARK 7782 ACCOUNTING -KING-CLARK-MILLER 7934 ACCOUNTING

118 SQL> select rpad(' ',level) sys_connect_by_path(ename,'-'), 2 empno, dname 3 from emp e, dept d 4 where d.deptno = e.deptno 5 start with mgr is null 6 connect by prior empno = mgr 7 ORDER SIBLINGS BY ENAME FULL_TREE EMPNO DNAME KING 7839 ACCOUNTING -KING-BLAKE 7698 SALES -KING-BLAKE-ALLEN 7499 SALES -KING-BLAKE-JAMES 7900 SALES -KING-BLAKE-WARD 7521 SALES -KING-CLARK 7782 ACCOUNTING -KING-CLARK-MILLER 7934 ACCOUNTING

119 119 "fine for EMP, my data is crap"

120 120

121 SQL> update emp set mgr = where ename = 'KING'; 1 row updated. SQL> select sys_connect_by_path(ename,'-') 2 from emp 3 start with ename = 'KING' 4 connect by prior empno = mgr 5 / ERROR: ORA-01436: CONNECT BY loop in user data 121

122 SQL> select sys_connect_by_path(ename,'-') 2 from emp 3 start with ename = 'KING' 4 connect by NOCYCLE prior empno = mgr 5 / SYS_CONNECT_BY_PATH(ENAME,'-') KING -KING-JONES -KING-JONES-SCOTT -KING-JONES-SCOTT-ADAMS -KING-JONES-FORD -KING-JONES-FORD-SMITH -KING-BLAKE

123 123 and still more...

124 SQL> insert into emp ( empno, ename, mgr, deptno) 2 values (1000,'DENNIS',null, 10); 1 row created. SQL> insert into emp ( empno, ename, mgr, deptno) 2 values (1001,'CHRIS',1000, 10); 1 row created. SQL> insert into emp ( empno, ename, mgr, deptno) 2 values (1002,'CRAIG',1001, 10); 1 row created. 124

125 SQL> select sys_connect_by_path(ename,'-') full_tree 2 from emp 3 start with mgr is null 4 connect by prior empno = mgr FULL_TREE KING -KING-BLAKE -KING-BLAKE-JAMES -KING-BLAKE-ALLEN -KING-BLAKE-WARD -KING-CLARK -KING-CLARK-MILLER -DENNIS -DENNIS-CHRIS -DENNIS-CHRIS-CRAIG am I a manager? who is my ultimate boss? 125

126 Who is top dog in my tree? SQL> select 2 connect_by_root ename, Am I a leaf node? 3 connect_by_isleaf, 4 connect_by_iscycle 5 from emp 6 start with mgr is null 7 connect by NOCYCLE prior empno = mgr 8 / Am I within a cycle? 126

127 SQL> select connect_by_root ename root, 2 connect_by_isleaf leaf, 3 connect_by_iscycle cyc, 4 sys_connect_by_path(ename,'-') full 5 from emp 6 start with ename in ('KING','DENNIS') 7 connect by NOCYCLE prior empno = mgr; ROOT LEAF CYC FULL KING 0 0 -KING KING 0 0 -KING-JONES KING 0 0 -KING-JONES-SCOTT KING 1 0 -KING-JONES-SCOTT-ADAMS KING 0 0 -KING-JONES-FORD KING 1 0 -KING-JONES-FORD-SMITH KING 0 0 -KING-BLAKE KING 1 1 -KING-BLAKE-ALLEN KING 1 0 -KING-BLAKE-WARD KING 1 0 -KING-BLAKE-MARTIN KING 1 0 -KING-BLAKE-TURNER KING 1 0 -KING-BLAKE-JAMES DENNIS 0 0 -DENNIS DENNIS 0 0 -DENNIS-CHRIS DENNIS 1 0 -DENNIS-CHRIS-CRAIG 127

128 128 "old style" hierarchy still cool...

129 has a new way...

130 130 first principles

131 SQL> select rpad(' ',level) ename, 2 from emp 3 start with mgr is null 4 connect by prior empno = mgr ENAME KING BLAKE JAMES ALLEN WARD CLARK MILLER 131

132 SQL> select empno, ename, mgr 2 from emp 3 where mgr is null; EMPNO ENAME MGR KING 132

133 SQL> select e2.empno, e2.ename, e2.mgr 2 from emp e2, 3 ( select empno, mgr 4 from emp 5 where mgr is null ) inner 6 where e2.mgr = inner.empno; EMPNO ENAME MGR JONES BLAKE CLARK

134 SQL> select e3.empno, e3.ename, e3.mgr 2 from emp e3, 3 ( select e2.empno, e2.ename, e2.mgr 4 from emp e2, 5 ( select empno, mgr 6 from emp 7 where mgr is null ) inner 8 where e2.mgr = inner.empno ) inner 9 where e3.mgr = inner.empno; EMPNO ENAME MGR FORD SCOTT JAMES TURNER MARTIN WARD MILLER

135 SQL> select e4.empno, e4.ename, e4.mgr 2 from emp e4, 3 ( select e3.empno, e3.ename, e3.mgr 4 from emp e3, 5 ( select e2.empno, e2.ename, e2.mgr 6 from emp e2, 7 ( select empno, mgr 8 from emp 9 where mgr is null ) inner 10 where e2.mgr = inner.empno ) inner 11 where e3.mgr = inner.empno ) inner 12 where e4.mgr = inner.empno; EMPNO ENAME MGR ADAMS recursive...

136 136

137 137 WITH can be recursive

138 138 SQL> with EACH_LEVEL (empno, name, mgr) as 2 ( start with select empno, ename, mgr 6 from emp 7 where mgr is null connect by union all 12 select emp.empno, emp.ename, emp.mgr 13 from emp, EACH_LEVEL 14 where emp.mgr = each_level.empno 15 ) 16 select * 17 from each_level;

139 EMPNO NAME MGR KING 7566 JONES BLAKE CLARK ALLEN WARD MARTIN SCOTT TURNER JAMES FORD MILLER SMITH ADAMS

140 140 two part structure

141 with RECURSIVE_WITH (c1,c2,c3) as ( <starting/entry point> union all <recursive relationship> ) select... from RECURSIVE_WITH 141

142 142 you control pseudo- functions

143 SQL> with each_level (empno, name, mgr, rlevel) as 2 ( select empno, ename, mgr, 1 rlevel 3 from emp 4 where mgr is null 5 union all 6 select emp.empno, emp.ename, emp.mgr, rlevel+1 7 from emp, each_level 8 where emp.mgr = each_level.empno 9 ) 10 select * from each_level; EMPNO NAME MGR RLEVEL KING JONES BLAKE CLARK ALLEN <etc> 143

144 SQL> with each_level (empno, name, mgr, level) as 2 ( select empno, ename, mgr, 1 level 3 from emp 4 where mgr is null 5 union all 6 select emp.empno, emp.ename, emp.mgr, level+1 7 from emp, each_level 8 where emp.mgr = each_level.empno 9 ) 10 select empno, name, mgr, level from each_level; with each_level (empno, name, mgr, level) as * ERROR at line 1: ORA-00904: : invalid identifier 144

145 145 SQL> with each_level (empno, name, mgr, rlevel) as 2 ( select empno, ename, mgr, 1 rlevel 3 from emp 4 where mgr is null 5 union all 6 select emp.empno, emp.ename, emp.mgr, rlevel+1 7 from emp, each_level 8 where emp.mgr = each_level.empno 9 ) 10 select empno, name, mgr, rlevel as "LEVEL" 11 from each_level;

146 SQL> with each_level (empno, name, mgr, padding) as 2 ( select empno, ename, mgr, '' padding 3 from emp 4 where mgr is null 5 union all 6 select e.empno, e.ename, e.mgr, padding ' ' 7 from emp e, each_level 8 where e.mgr = each_level.empno 9 ) 10 select empno, padding name name 11 from each_level; ERROR: ORA-01489: result of string concatenation is too long 146

147 SQL> with each_level (empno, name, mgr, padding) as 2 ( select empno, ename, mgr, 3 cast('' as varchar2(100)) padding 4 from emp 5 where mgr is null 6 union all 7 select e.empno, e.ename, e.mgr, padding ' ' 8 from emp e, each_level 9 where e.mgr = each_level.empno 10 ) 11 select empno, padding name name 12 from each_level; EMPNO NAME KING 7566 JONES

148 148 SQL> with each_level (empno, name) as 2 ( select empno, ename from emp 3 where mgr is null 4 union all 5 select e.empno, 6 each_level.name '-' e.ename 7 from emp e, each_level 8 where e.mgr = each_level.empno 9 ) 10 select empno, name from each_level; EMPNO NAME KING 7566 KING-JONES 7698 KING-BLAKE 7782 KING-CLARK 7499 KING-BLAKE-ALLEN 7521 KING-BLAKE-WARD <etc>

149 149 cycle detection as before...

150 SQL> update emp set mgr = where ename = 'KING'; 1 row updated. SQL> select empno, rpad(' ',level) ename ename, mgr 2 from emp 3 connect by prior empno = mgr 4 start with ename = 'KING'; ERROR: ORA-01436: CONNECT BY loop in user data 150

151 SQL> with each_level (empno, name, mgr) as 2 ( select empno, ename, mgr 3 from emp 4 where ename = 'KING' 5 union all 6 select emp.empno, emp.ename, emp.mgr 7 from emp, each_level 8 where emp.mgr = each_level.empno 9 ) 10 select * 11 from each_level; ERROR: ORA-32044: cycle detected while executing recursive WITH query 151

152 152...but the results are different

153 SQL> select empno, ename, mgr, 2 connect_by_iscycle 3 from emp 4 connect by NOCYCLE prior empno = mgr 5 start with ename = 'KING'; EMPNO ENAME MGR CONNECT_BY_ISCYCLE KING JONES BLAKE ALLEN WARD MARTIN [snip] 14 rows selected. 153

154 154 SQL> with each_level (empno, name, mgr) as 2 ( select empno, ename, mgr from emp 3 where ename = 'KING' 4 union all 5 select emp.empno, emp.ename, emp.mgr 6 from emp, each_level 7 where emp.mgr = each_level.empno ) 8 CYCLE mgr SET is_cycle TO 'Y' DEFAULT 'N' 9 select * from each_level; EMPNO NAME MGR IS_CYCLE KING 7499 N 7566 JONES 7839 N 7521 WARD 7698 N 7839 KING 7499 Y 7876 ADAMS 7788 N [snip] 15 rows selected.

155 SQL> with each_level (empno, name, mgr) as 2 ( select empno, ename, mgr from emp 3 where ename = 'KING' 4 union all 5 select emp.empno, emp.ename, emp.mgr 6 from emp, each_level 7 where emp.mgr = each_level.empno 8 ) 9 CYCLE mgr SET is_cycle TO 'YES' DEFAULT 'NO' 10 select * from each_level; * ERROR at line 9: ORA-32047: cycle mark value and non-cycle mark value must be one byte character string values 155

156 156 some nice touches...

157 SQL> with each_level (empno, name, hiredate, mgr) as 2 ( select empno, ename, hiredate, mgr from emp 3 where ename = 'KING' 4 union all 5 select e.empno, 6 each_level.name '-' e.ename, e.hiredate, e.mgr 7 from emp e, each_level 8 where e.mgr = each_level.empno ) 9 SEARCH BREADTH FIRST BY HIREDATE SET IDX 10 select name, hiredate, idx from each_level; NAME HIREDATE IDX KING 17-NOV-81 1 KING-JONES 02-APR-81 2 KING-BLAKE 01-MAY-81 3 KING-CLARK 09-JUN-81 4 KING-BLAKE-ALLEN 20-FEB-81 5 KING-BLAKE-WARD 22-FEB-81 6 [snip] KING-JONES-FORD-SMITH 17-DEC KING-JONES-SCOTT-ADAMS 23-MAY

158 SQL> with each_level (empno, name, hiredate, mgr) as 2 ( select empno, ename, hiredate, mgr from emp 3 where ename = 'KING' 4 union all 5 select e.empno, 6 each_level.name '-' e.ename, e.hiredate, e.mgr 7 from emp e, each_level 8 where e.mgr = each_level.empno ) 9 SEARCH DEPTH FIRST BY HIREDATE SET IDX 10 select name, hiredate, idx from each_level; NAME HIREDATE IDX KING 17-NOV-81 1 KING-JONES 02-APR-81 2 KING-JONES-FORD 03-DEC-81 3 KING-JONES-FORD-SMITH 17-DEC-80 4 KING-JONES-SCOTT 19-APR-87 5 KING-JONES-SCOTT-ADAMS 23-MAY-87 6 KING-BLAKE 01-MAY-81 7 KING-BLAKE-ALLEN 20-FEB-81 8 etc 158

159 159 performance

160 1,2,3,4,5,6,7,8,9 11,12,13,14,15,16,17,18,19 21,22,23,24,25,26,27,28,29 111,112,113,114,115,116,117,118,119 etc... 5,380,839 rows 160

161 161 need a big hierarchy

162 SQL> create table BIG_HIER nologging as 2 with hier(x,y, lev) as 3 ( select rownum x,null y,1 lev 4 from dual connect by level < 10 5 union all 6 select 10*x+p, x, lev+1 7 from hier, 8 ( select level p from dual 9 connect by level < 10 ) 10 where lev < 7 11 ) 12 select * from hier; Table created. 162

163 SQL> begin 2 dbms_stats.gather_table_stats(user,'big_hier'); 3 end; PL/SQL procedure successfully completed. SQL> create index IX1 on BIG_HIER ( x ); Index created. SQL> create index IX2 on BIG_HIER ( y ); Index created. 163

164 SQL> select * 2 from big_hier 3 start with y is null 4 connect by prior x = y; Id Operation Name Rows Cost (%CPU) SELECT STATEMENT (1) 1 CONNECT BY WITH FILTERING 2 TABLE ACCESS FULL BIG_HIER (1) 3 NESTED LOOPS (1) 4 CONNECT BY PUMP 5 TABLE ACCESS BY INDEX ROWID BIG_HIER 9 3 (0) 6 INDEX RANGE SCAN IX2 9 2 (0)

165 SQL> with bench(x,y,lev) as 2 ( select x,y, lev from big_hier 3 where y is null 4 union all 5 select h.x,h.y,h.lev 6 from big_hier h, bench b 7 where h.y = b.x ) 8 select * from bench; Id Operation Name Rows Cost (%CPU) SELECT STATEMENT (1) 1 VIEW (1) 2 UNION ALL (RECURSIVE WITH) BREADTH FIRST 3 TABLE ACCESS FULL BIG_HIER (1) 4 NESTED LOOPS 5 NESTED LOOPS (1) 6 RECURSIVE WITH PUMP 7 INDEX RANGE SCAN IX2 9 2 (0) 8 TABLE ACCESS BY INDEX ROWID BIG_HIER 9 3 (0)

166 SQL> select * 2 from big_hier 3 start with y is null 4 connect by prior x = y; rows selected. Elapsed: 00:04:46.12 Statistics recursive calls db block gets consistent gets physical reads 7 sorts (memory) 2 sorts (disk) 166

167 SQL> with bench(x,y,lev) as 2 ( select x,y, lev from big_hier 3 where y is null 4 union all 5 select h.x,h.y,h.lev 6 from big_hier h, bench b 7 where h.y = b.x ) 8 select * from bench; rows selected. Elapsed: 00:04: Statistics recursive calls db block gets consistent gets physical reads 7 sorts (memory) 1 sorts (disk)

168 get used to it... ANSI 168

169 169 favourite: query blocks

170 C#, C++ OSB Tuxedo Weblogic PL/SQL 170

171 for (int i = 0; i < WinningCombinations.Count; ++i) { if (WinningCombinations[i].Investment > 0 && WinningCombinations[i].PrimaryDividend > MinDividendDeadHeat) { maxdivisor = Math.Max(maxDivisor, WinningCombinations[i].Divisor); } } for (int i = 0; i < WinningCombinations.Count; ++i) { if (WinningCombinations[i].Investment > 0 && WinningCombinations[i].PrimaryDividend > MinDividendDeadHeat) { WinningCombinations[i].Divisor = maxdivisor / WinningCombinations[i].Divisor; sumnewdivisors += WinningCombinations[i].Divisor; } } 171

172 172 no comments

173 173

174 174 "C# is self-documenting"

175 for (int i = 0; i < WinningCombinations.Count; ++i) { if (WinningCombinations[i].Investment > 0 && WinningCombinations[i].PrimaryDividend > MinDividendDeadHeat) { maxdivisor = Math.Max(maxDivisor, WinningCombinations[i].Divisor); } } for (int i = 0; i < WinningCombinations.Count; ++i) { if (WinningCombinations[i].Investment > 0 && WinningCombinations[i].PrimaryDividend > MinDividendDeadHeat) { WinningCombinations[i].Divisor = maxdivisor / WinningCombinations[i].Divisor; sumnewdivisors += WinningCombinations[i].Divisor; } } 175

176 for (int i = 0; i < w.count; ++i) { if (w[i].v > 0 && w[i].p > mddh) { m = Math.Max(m, w[i].d); } } for (int i = 0; i < w.count; ++i) { if (w[i].v > 0 && w[i].p > mddh) { w[i].d = m / w[i].d; s += w[i].d; } } 176

177 query blocks = self- documenting SQL 177

178 select emp.* from emp, ( select trunc(hiredate,'yyyy'), max(empno) empno from emp where empno > 0 group by trunc(hiredate,'yyyy') ) x, ( select deptno, avg(sal) from emp group by deptno ) y where x.empno = emp.empno and y.deptno = emp.deptno 178

179 179 Id Operation Name SELECT STATEMENT 1 HASH JOIN 2 TABLE ACCESS BY INDEX ROWID EMP 3 NESTED LOOPS 4 VIEW 5 SORT GROUP BY 6 TABLE ACCESS BY INDEX ROWID EMP 7 INDEX FULL SCAN E2 8 INDEX RANGE SCAN E1 9 VIEW 10 SORT GROUP BY 11 TABLE ACCESS BY INDEX ROWID EMP 12 INDEX RANGE SCAN E2

180 select emp.* from emp, ( select /*+ QB_NAME(YR_HIRE) */ trunc(hiredate,'yyyy'), max(empno) empno from emp where empno > 0 group by trunc(hiredate,'yyyy') ) x, ( select /*+ QB_NAME(AV_SAL) */ deptno, avg(sal) from emp group by deptno ) y where x.empno = emp.empno and y.deptno = emp.deptno 180

181 Id Operation Name Query Block SELECT STATEMENT 1 HASH JOIN SEL$1 2 TABLE ACCESS BY INDEX ROWID EMP SEL$1 3 NESTED LOOPS 4 VIEW AV_SAL 5 SORT GROUP BY AV_SAL 6 TABLE ACCESS BY INDEX ROWID EMP AV_SAL 7 INDEX FULL SCAN E2 AV_SAL 8 INDEX RANGE SCAN E1 SEL$1 9 VIEW YR_HIRE 10 SORT GROUP BY YR_HIRE 11 TABLE ACCESS BY INDEX ROWID EMP YR_HIRE 12 INDEX RANGE SCAN E2 YR_HIRE 181

182 182 assist with query trace

183 SQL> alter session set 2 events = '10053 trace name context forever, level 1'; Session altered. 183

184 ************************** Query transformations (QT) ************************** CBQT: Validity checks passed for 7jpzpr2475cqw. CSE: Sub-expression elimination in query block SEL$1 (#0) ************************* Common Subexpression elimination (CSE) ************************* CSE: CSE not performed on query block YR_HIRE (#0). CSE: Sub-expression elimination in query block AV_SAL (#0) CSE: CSE not performed on query block AV_SAL (#0). CSE: CSE not performed on query block SEL$1 (#0). *************************** Order-by elimination (OBYE) *************************** OBYE: Considering Order-by Elimination from view SEL$1 (#0) 184

185 ********************************* Number of join permutations tried: 1 ********************************* GROUP BY adjustment factor: GROUP BY cardinality: , TABLE cardinality: SORT ressource Sort statistics Sort width: 598 Area size: Max Area: Degree: 1 Blocks to Sort: 1 Row size: 18 Total Rows: 14 Initial runs: 1 Merge passes: 0 IO Cost / pass: 0 Total IO sort cost: 0 Total CPU sort cost: Total Temp space used: 0 Trying or-expansion on query block AV_SAL (#3) Transfer Optimizer annotations for query block AV_SAL (#3) GROUP BY adjustment factor: Final cost for query block AV_SAL (#3) - All Rows Plan: Best join order: 1 Cost: Degree: 1 Card: Bytes: 98 Resc: Resc_io: Resc_cpu: Resp: Resp_io: Resc_cpu:

186 186 assist with hints

187 select /*+ QB_NAME(top) emp (empno)) emp) */ emp.* from emp, ( select /*+ QB_NAME(YR_HIRE) */ trunc(hiredate,'yyyy'), max(empno) empno from emp where empno > 0 group by trunc(hiredate,'yyyy') ) x, ( select /*+ QB_NAME(AV_SAL) */ deptno, avg(sal) from emp group by deptno ) y where x.empno = emp.empno and y.deptno = emp.deptno 187

188 select /*+ QB_NAME(top) emp (empno)) emp) */ INDEX(emp emp_ix) 188

189 189 favourite: scalar queries

190 SQL> select 2 ( select dname 3 from dept 4 where deptno = e.deptno ) dname, 5 decode(empno, 7499, 6 ( select max(sal) from emp ), 7-1) 8 from 9 ( select * from emp 10 where sal > 0 ) e 11 where scalar anywhere an expression could be 12 ( select max(hiredate) from emp ) < sysdate 13 / 190

191 191 "big deal"

192 SQL> create or replace 2 function DEMO(p int) return number is 3 begin 4 dbms_lock.sleep(1); 5 return p; 6 end; 7 / Function created. 1,2,3,..., 30 SQL> create table T 2 as select rownum r, mod(rownum,5) r1 from dual 3 connect by level <= 30; Table created. 0,1,2,3,4,0,1,2,3,4,

193 SQL> select r, demo(r1) from T; R DEMO(R1) rows selected. Elapsed: 00:00:

194 SQL> select r, 2 ( select demo(r1) from dual) as res 3 from T; R RES rows selected. Elapsed: 00:00:

195 subquery caching... any subquery 195

196 196 what about multiple values

197 197 SQL> select 2 empno, 3 ( select dname, loc, revenue 4 from dept 5 where deptno = e.deptno ) 6 from EMP e; ( select dname, loc, revenue * ERROR at line 3: ORA-00913: too many values

198 SQL> select 2 empno, 3 ( select dname 4 from dept 5 where deptno = e.deptno ) dname, 6 ( select loc 7 from dept 8 where deptno = e.deptno ) loc, 9 ( select revenue 10 from dept 11 where deptno = e.deptno ) rev 12 from EMP e; 198 EMPNO DNAME LOC REV ACCOUNTING NEW YORK SALES CHICAGO ACCOUNTING NEW YORK RESEARCH DALLAS [snip]

199 199 use a type

200 SQL> create type multi_attrib as object ( 2 dname varchar2(10), 3 loc varchar2(10), 4 rev number ); 5 / Type created. 200

201 SQL> select empno, 2 x.attr.dname, 3 x.attr.loc, 4 x.attr.rev 5 from 6 ( 7 select 8 empno, 9 ( select multi_attrib( 10 dname,loc,revenue) 11 from dept 12 where deptno = e.deptno ) attr 13 from EMP e 14 ) x; EMPNO ATTR.DNAME ATTR.LOC ATTR.REV ACCOUNTING NEW YORK SALES CHICAGO ACCOUNTING NEW YORK

202 subquery caching _query_execution_cache_max_size Source: "Cost Based Oracle" 202

203 203 DML error logging

204 SQL> insert into MY_TABLE 2 select * 3 from MY_WHOPPING_GREAT_FAT_TABLE; Elapsed: 06:12:34.00 ERROR at line 1: ORA-00001: unique constraint (DEMO.WHOPPER_PK) violated 204

205 insert update delete merge 205

206 keeps successful rows logs error rows 206

207 error logging table ERR$_MY_TABLE 207

208 208 SQL> exec DBMS_ERRLOG.CREATE_ERROR_LOG('EMP')

209 SQL> desc ERR$_EMP Name Null? Type ORA_ERR_NUMBER$ NUMBER ORA_ERR_MESG$ VARCHAR2(2000) ORA_ERR_ROWID$ ROWID ORA_ERR_OPTYP$ VARCHAR2(2) ORA_ERR_TAG$ VARCHAR2(2000) EMPNO VARCHAR2(4000) ENAME VARCHAR2(4000) JOB VARCHAR2(4000) MGR VARCHAR2(4000) HIREDATE VARCHAR2(4000) SAL VARCHAR2(4000) COMM VARCHAR2(4000) DEPTNO VARCHAR2(4000) 209

210 Column Name Data Type Description ORA_ERR_NUMBER$ NUMBER Oracle error number ORA_ERR_MESG$ VARCHAR2(2000) Oracle error message text ORA_ERR_ROWID$ ROWID Rowid of the row in error (update and delete only) ORA_ERR_OPTYP$ VARCHAR2(2) Type of operation I = insert, U = update, D = delete ORA_ERR_TAG$ VARCHAR2(2000) User supplied tag 210

211 SQL> select * from NEW_DATA; EMPNO SAL DEPTNO X SQL> 2500 exec dbms_errlog.create_error_log( 50 'EMP' ); PL/SQL procedure successfully completed. SQL> insert into EMP (empno,sal,deptno) 2 select * 3 from NEW_DATA 4 LOG ERRORS REJECT LIMIT UNLIMITED; 1 row created. SQL> select ORA_ERR_OPTYP$ op, ORA_ERR_MESG$, EMPNO 2 from err$_emp OP ORA_ERR_MESG$ EMPNO I ORA-01722: invalid number 100X I ORA-02291: integrity constraint (SCOTT.FK_DEPTNO) violated 2000 I ORA-00001: unique constraint (SCOTT.PK_EMP) violated

212

213 213 IGNORE_ROW_ON_DUPKEY_INDEX

214 total recall 11g 214

215 SQL> create tablespace SPACE_FOR_ARCHIVE 2 datafile 'C:\ORACLE\DB11\ARCH_SPACE.DBF' 3 size 100M; Tablespace created. SQL> CREATE FLASHBACK ARCHIVE longterm 2 TABLESPACE space_for_archive 3 RETENTION 1 YEAR; Flashback archive created. 215

216 SQL> ALTER TABLE EMP FLASHBACK ARCHIVE LONGTERM; Table altered. [lots of DML] SQL> select * from EMP; Id Operation Name Rows Bytes SELECT STATEMENT TABLE ACCESS FULL EMP

217 SQL> select * from EMP 2 AS OF TIMESTAMP SYSDATE-3; Id Operation Name Rows Bytes SELECT STATEMENT TABLE ACCESS FULL EMP

218 [lots more DML] SQL> select * from EMP 2 AS OF TIMESTAMP SYSDATE-3; Id Operation Name Rows SELECT STATEMENT VIEW UNION-ALL * 3 FILTER 4 PARTITION RANGE ITERATOR 445 * 5 TABLE ACCESS FULL SYS_FBA_HIST_ * 6 FILTER * 7 HASH JOIN OUTER 1 * 8 TABLE ACCESS FULL EMP 1 9 VIEW 14 * 10 TABLE ACCESS FULL SYS_FBA_TCRV_

219 SQL> select table_name 2 from user_tables 3 / TABLE_NAME SYS_FBA_HIST_71036 SYS_FBA_TCRV_71036 SYS_FBA_DDL_COLMAP_71036 EMP 219

220 SQL> select dbms_metadata.get_ddl( 'TABLE', 'SYS_FBA_HIST_71036') from dual; CREATE TABLE "SCOTT"."SYS_FBA_HIST_71036" ( "RID" VARCHAR2(4000), "STARTSCN" NUMBER, "ENDSCN" NUMBER, "XID" RAW(8), "OPERATION" VARCHAR2(1), "EMPNO" NUMBER(4,0), "ENAME" VARCHAR2(10), "JOB" VARCHAR2(9), "MGR" NUMBER(4,0), "HIREDATE" DATE, "SAL" NUMBER(7,2), "COMM" NUMBER(7,2), "DEPTNO" NUMBER(2,0) ) COMPRESS FOR ALL OPERATIONS TABLESPACE "SPACE_FOR_ARCHIVE" PARTITION BY RANGE ("ENDSCN") ( PARTITION "HIGH_PART" VALUES LESS THAN (MAXVALUE) ) 220

221 SQL> select dbms_metadata.get_ddl( 'TABLE', 'SYS_FBA_TCRV_71036') from dual; CREATE TABLE "SCOTT"."SYS_FBA_TCRV_71036" ( "RID" VARCHAR2(4000), "STARTSCN" NUMBER, "ENDSCN" NUMBER, "XID" RAW(8), "OPERATION" VARCHAR2(1) ) TABLESPACE "SPACE_FOR_ARCHIVE" 221

222 SQL> select * from EMP 2 AS OF TIMESTAMP SYSDATE-3; Id Operation Name Rows SELECT STATEMENT VIEW UNION-ALL * 3 FILTER 4 PARTITION RANGE ITERATOR 445 * 5 TABLE ACCESS FULL SYS_FBA_HIST_ * 6 FILTER * 7 HASH JOIN OUTER 1 * 8 TABLE ACCESS FULL EMP 1 9 VIEW 14 * 10 TABLE ACCESS FULL SYS_FBA_TCRV_

223 223 all your history...

224 224 all your audit...

225 225 restrictions #1

226 SQL> alter table EMP RENAME column job to jobtitle; * ERROR at line 1: ORA-55610: Invalid DDL statement on history-tracked table SQL> alter table emp DROP column dummy; alter table scott.emp drop column dummy * ERROR at line 1: ORA-55610: Invalid DDL statement on history-tracked table SQL> alter table emp ADD dummy int; Table altered. 226

227 be careful... no spanning DDL might apply 227

228 better in 11.2 DBMS_FLASHBACK_ARCHIVE.DISASSOCIATE_FBA DBMS_FLASHBACK_ARCHIVE.REASSOCIATE_FBA 228

229 229 restrictions #2

230 230

231 Feature: sql transposition 231

232 232 rows to columns, colums to rows

233 "I need sales by product for each quarter...now" 233

234 SQL> select product, 2 trunc(txn_date,'q') mth, sum(quantity) total 3 from SALES 4 group by product,trunc(txn_date,'q') 5 order by 1,2; 234 PRODUCT MTH TOTAL CHAINSAW JAN CHAINSAW APR CHAINSAW JUL CHAINSAW OCT HAMMER JAN HAMMER APR HAMMER JUL HAMMER OCT SCREW DRIVER JAN SCREW DRIVER APR SCREW DRIVER JUL SCREW DRIVER OCT SPADE JAN SPADE APR SPADE JUL SPADE OCT WHEEL BARROW JAN WHEEL BARROW APR WHEEL BARROW JUL WHEEL BARROW OCT

235 "That s crap...surely you know I wanted it ACROSS the page" 235

236 236

237 237

238 and below

239 SQL> select 2 product 3,sum(case when trunc(txn_date,'q')='jan' then qty end) jan 4,sum(case when trunc(txn_date,'q')='apr' then qty end) apr 5,sum(case when trunc(txn_date,'q')='jul' then qty end) jul 6,sum(case when trunc(txn_date,'q')='oct' then qty end) oct 7 from SALES 8 group by product 9 order by 1 10 / PRODUCT JAN APR JUL OCT CHAINSAW HAMMER SCREW DRIVER SPADE WHEEL BARROW

240 240 11g pivot clause

241 SQL> select * 2 from (select product, 3 trunc(txn_date,'q') mth, 4 quantity 5 from sales ) 6 pivot( sum(quantity) for mth in 7 ( 'JAN', 8 'APR', 9 'JUL', 10 'OCT') ) 11 order by 1 12 / PRODUCT 'JAN' 'APR' 'JUL' 'OCT' CHAINSAW HAMMER SCREW DRIVER SPADE WHEEL BARROW

242 242 "nah...make it go DOWN the page

243 SQL> create table PIVOTED_SALES as select * 2 from (select product, 3 trunc(txn_date,'q') mth, 4 quantity 5 from sales ) 6 pivot( sum(quantity) for mth in 7 ( 'JAN', 8 'APR', 9 'JUL', 10 'OCT') ) 11 order by 1 12 / Table created. 243

244 244 unpivot clause

245 SQL> desc PIVOTED_SALES Name Null? Type PRODUCT VARCHAR2(20) Q1 NUMBER Q2 NUMBER Q3 NUMBER Q4 NUMBER 245

246 SQL> select * 2 from PIVOTED_SALES 3 UNPIVOT 4 ( quantity for quarter in (Q1,Q2,Q3,Q4) ) 5 / column values become "quantity" 246 PRODUCT QUARTER QUANTITY CHAINSAW Q CHAINSAW Q CHAINSAW Q CHAINSAW Q HAMMER Q HAMMER Q HAMMER Q HAMMER Q SCREW DRIVER Q SCREW DRIVER Q SCREW DRIVER Q SCREW DRIVER Q SPADE Q SPADE Q SPADE Q SPADE Q WHEEL BARROW Q WHEEL BARROW Q WHEEL BARROW Q WHEEL BARROW Q column names become "quarter"

247 247 elements must be known in advance

248 248

Spool Generated For Class of Oracle By Satish K Yellanki

Spool Generated For Class of Oracle By Satish K Yellanki SQL> CREATE VIEW Employees 3 SELECT 4 Empno "ID Number", 5 Ename Name, 6 Sal "Basic Salary", 7 Job Designation 8 FROM Emp; SQL> SELECT 2 Empno "ID Number", 3 Ename Name, 4 Sal "Basic Salary", 5 Job Designation