Joe Celko s SQL for Smarties - Advanced SQL Programming P84 pot

in limiting user access, 45reconstruction as, 160–61 updating rule, 63 valid-time state, 166 View Updating Rule, 63 Virtual tables, 3 Virtual views... He is well known for his 10 years o

SELECT, 58, 143–44, 317–68

SET TRANSACTION, 724–25

UPDATE, 58–59, 223–30

State transition model, 670

Static SQL

compilation, 756

recompiling, 756–57

Statistics, 509–48

average deviation, 528

AVG() function, 512

cross tabulations, 538–45

cumulative, 528–38

cumulative percentages, 531–33

descriptive, 509

geometric mean, 545–46

harmonic mean, 545–46

median, 512–27

mode, 510–12

multivariable descriptive, 546–48

quintiles, 537–38

rankings, 533–37

running differences, 530–31

running totals, 529–30

standard deviation, 527–28

updating, 760

Storage

date, 658

GUID requirement, 42

IP address, 202–5

physically contiguous, 90

temporary table, 51

Strings

case, changing, 170–71

character content, 269–70

declaring, 270

defined, 170

dummy, 196

equality, 170–71

expressions, 738

functions, 172–73

grouping, 172

index creation on, 271 length, 172

MAX() function for, 449

MIN() value for, 450 ordering, 171 problems, 170–72 searching, 270 tricks with, 269–71 Subordinates, 635 finding, 630 junior, 635 senior, 635 Subqueries columnar, 257 constants and, 257–58 correlated, 310, 324–26, 436 crosstabs by, 544–45

DEFAULT clauses and, 608 empty, 315

execution, 290 grouped, 362

IN() predicates with, 288 for multiple aggregation levels, 433–34

nesting, 454

in NOT EXISTS() predicates, 435 row, 257, 310

scalar, 257, 433 scalar comparisons, 310–11

SELECT DISTINCT in, 314 table, 433

tabular, 257

TRUE, 315 types of, 257 Subregions, finding, 550–51 Subscripts

columns, arrays via, 580–81 data types, 581

in declared range, 580

as enumerations, 585 Subsequences, 549, 554

Subsets, 605–22

alphabetical ordering, 437

equality, 617–18

minimum, 620

operators, proper, 612–13

proper, equality and, 602–3

representative, picking, 618–22

row, finding, 618

SUBSTRING() function, 172, 467

empty string return, 355

joining tables with, 355

Substrings

integer, 485

operator, 381

Subtrees

deleting, 630–31, 636–37

finding, 629–30

See also Trees

SUM() function, 107, 443–44

ALL keyword, 443

defined, 443

DISTINCT keyword, 470

SUM keyword, 443

Summation of a series, 562–65

complexity, 564

running total, 562

Swaps

chain, 95

minimum number of, 95

pairs, 94

Swedish solution, 364

Sybase/SQL Server model, 759

Systematic Treatment of NULL Values,

62

T Tables

3NF, 79

4NF, 76

altering, 628

attribute split, 31–33

auxiliary, 477–507

base, 44 BCNF, 73–74 bitemporal, 164–67 calendar, 567 calendar auxiliary, 673–75 constraints, 5

Cutter, 182–83 cyclic data, 643 deleting in, 216–19 derived, 353–54, 395–97 EKNF, 72, 73

empty, 187 equality, 613–18 flattening, 93 flattening, with VIEWs, 393–95 global constants, 506–7

grouped, 428 indexing, 740–42 loading with query, 355 lookup, 296

manipulating, 5–10 missing, 187 modeling time in, 670–73 name, 5

operations, 211–34 persistent, 3 preserved, 347 random rows, picking, 607–12 redundant duplicates, 217–18 rolling back, 160

schema, 50–51 sequence, 477–85 single-column range, 402–3 spreadsheets vs., 5

temporal granularity, 136 temporary, 51, 390–91, 757–60 timestamped, 131

transaction-time state, 156–58 unpreserved, 347

updating, 97 valid-time state, 136, 145–46

virtual, 3, 369

See also Columns; rows

Tabular subqueries, 257

Temporal databases, 135–37

Temporal data models, 129–67

Temporal data types, 119–67

converting, 236

MAX() function for, 449

MIN() function for, 449–50

Temporal duplicates, 129–35

current, 131, 133

defined, 131

interaction, 132

nonsequenced, 133

sequenced, 132, 134, 135

value-equivalent, 132–33

See also Duplicates

Temporal JOINs, 139–45

Temporal math, 642–45

Temporal projection/selection, 137–39

Temporal queries, 641–80

calendar auxiliary table, 673–75

date/time extraction functions,

665–66

Julian dates, 661–65

math, 642–43

modeling time in tables, 670–73

personal calendars, 643–45

time series, 645–61

weeks, 667–70

year 2000 problem, 675–80

See also Queries

Temporal starting/ending points, 658–

60

Temporal support, 167

Temporary tables, 51

creating, on fly, 393

declarations, 390–91

global, 51, 392

for intermediate results, 757

local, 51, 392

storage space, 51 usefulness, 757–60 using, 392–93

VIEWs and, 391–95

See also Tables

Text, in-line expansion, 380–82 Theta operators, 235–40 Third Normal Form (3NF), 71–72 with CASE tools, 78

normalization algorithm, 79 tables, 79

See also Normal forms

Three-valued logic (3VL), 193, 306–8

TIME data type, 123, 167 Timelines

diagram of overlapping cases, 279 diagrams, 280, 282

partitioned into intervals, 645 Time(s)

average wait, 660–61 CUT, 122

DST, 127 durations, 128 fixed events, 128 format, 128 handling, 127–28 handling tips, 124 intervals, 128 missing, in contiguous events, 652–56

modeling in tables, 670–73 overlapping, 277

user-defined, 135 UTC, 122–23, 127, 128 Time series, 645–61

average wait times, 660–61 continuous time periods, 648–52 gaps in, 645–48

locating dates, 656–58 missing times, 652–56 starting/ending points, 658–60

See also Temporal queries

TIMESTAMP data type, 123, 167

time-varying data support with,

167

as unique identifiers, 126

Timestamps

handling, 125–27

handling tips, 124

purposes, 125

T-joins, 359–68

approaches, 360–61

Ascending Order Algorithm, 360

Colombian solution, 364–68

condition, maintaining, 361

Croatian solution, 363–64

defined, 359

Descending Order Algorithm, 361

procedural algorithm, 363

Swedish solution, 364

tables, 359–60

See also JOINs

Todd’s division, 410–12

Transactions

ACID properties and, 720–22

deadlocks, 730

isolation levels, 724–26

livelocks, 730

Transaction-time tables, 156–58

challenge, 156

characterizations, 156–57

example, 157–58

modeling, 156

modifications, 164

nonsequenced queries, 162, 163

sequenced queries, 162, 163

See also Tables

Transitive dependencies, 71, 72

3NF and, 71, 72

computed columns, 72

removal, 74

Translated columns, 373–74

TRANSLATE() function, 173 Translation auxiliary tables, 487–88 multiple, 487–88

simple, 487

See also Auxiliary tables

Transposition, matrix, 585 Traversal

hiding, 628 modified preorder tree algorithm, 633

procedural, 627–28 Trees

adjacency list model, 624–28 binary, 623

defined, 623 defining, 624

as directed graphs, 681 edge, deleting, 628 model choices, 639–40 modified preorder, 633 nodes, 623

path enumeration model, 628–31 root, 623

specialized, 639 structure, 624

TRIGGERs, 27 advantages, 53 code, 39–40 declaring, 52–53 defined, 52 disadvantages, 53 performance, 29 uses, 53

Triggers audit logs and, 158

DELETE, 160

INSERT, 160

INSTEAD OF, 28, 36

UPDATE, 160

TRIM() function, 173, 264, 467

TRUNCATE() function, 117, 663, 664

Truncation, 105–6

defined, 105, 444

negative numbers, 444

positive numbers, 444

U UNION ALL operator, 68, 143, 375,

592–96, 617

defined, 592

duplicate preservation, 593

mixed, 595

optimizing, 593

order of execution, 594–95

syntax, 592

See also Set operators

UNIONed VIEWs, 375–77

UNION JOINs, 356–57

defined, 350, 356

illustrated, 351

use, 356–57

See also JOINs

UNION operator, 142, 143, 375, 592–

96, 617

avoiding, 744

behavior, 602

defined, 592

implementation, 744

mixed, 595

optimizing, 593

order of execution, 594–95

syntax, 592

UNION ALL to replace, 744

See also Set operators

UNIQUE constraints, 14, 741

defined, 14

nested, 18–22

UNIQUE indexes vs., 17

UNIQUE indexes, 17

Uniqueness constraints, 31

UNIQUE predicate, 314–15

defined, 314

syntax, 314–15

Universal Coordinated Time (UTC),

122–23, 127, 128 Unload utilities, 223 Updatable VIEWs, 371–73 defined, 371

queries, 372 queries criteria, 371

See also VIEWs

Updates audit logs, 158 bitemporal table, 165 logical current, 148–50 with second table, 226–28 sequenced, 152–55 statistics, 760 tables, 97

UPDATE statement, 27, 223–30, 583 with CASE expression, 228–30 defined, 223

error message, 227

FROM clause, 231 positioned, 58–59 searched, 226 with second table, 226–28

SET clause, 224, 225–26 syntax, 223–24

WHERE clause, 224–25, 228, 230 User-controlled keys, 91

USING clause, 327

V Valid-time state tables, 136

current deletion on, 147–48 current modifications, 146–50 current update on, 148–50 modifying, 145–46

nonsequenced modifications, 155 sequenced deletion on, 150–52 sequenced modifications, 150–55 sequenced update on, 152–55

See also Tables

Valued predicates, 241–45

IS [NOT] TRUE | FALSE |

UNKNOWN, 242–44

IS NULL, 241–42

Value-equivalent duplicates, 132–33

Value generators, 42–44

Values

approximate, 198

average, 445

calibration, 652

insertion, 221

last allocated, 43

missing, 109, 187–90

multiple missing, 199

negative, 114

NULL, multiple, 198–200

preallocated, 44–45

random order, 45–48

seed, 609

sorting, 333

swapping/sliding, 565–67

VALUES constructor, 397, 481

VARCHAR() data type, 169

Vaughan’s median, 519–20

Vendor extensions, 174–82

defined, 174

flaws, 231–32

FLIP(), 175

NUMTOWORDS(), 175

phonetic matching, 175–82

REPLACE(), 174

REPLICATE(), 174

REVERSE(), 175

SPACE(), 174

Vendor math functions, 113–18

exponential functions, 116

numbers to words conversion,

117–18

number theory operators, 113–16

scaling functions, 116–17

VIEWs

building, 282, 283–84

calculated columns, 373 changed, 371

defined, 369 definition, 370 dropping, 389–90 existence, 370 flattening, 393–95

GROUP BY clause and, 381, 432 grouped, 290, 374–75

grouped, for multiple aggregation levels, 432

handling in database system, 379– 83

hiding in, 36 indexing and, 383 in-line text expansion, 380–82

JOINs in, 377 key, 371 materialization, 379–80 multitable, 383

names, 370 nested, 370, 377–79 pointer structures, 382–83

in queries, 370 read-only, 371–73, 374 recursive, 688

with schema-level constraints, 25– 29

for security, 392 single-table projection/restriction, 373

syntax, 370 temporary tables and, 391–95 translated columns, 373–74 types of, 373–79

UNIONed, 375–77 updatable, 371–73 Vaughan’s median with, 519–20

WITH CHECK OPTION clause, 383–89

Views

in limiting user access, 45

reconstruction as, 160–61

updating rule, 63

valid-time state, 166

View Updating Rule, 63

Virtual tables, 3

Virtual views See VIEWs

VLDB (Very Large Databases), 39

WWeeks, 667–70

example, 668–69

weekday name sorting, 669–70

WHEN clause

CASE expressions, 248, 249, 250

in sequence numbers, 561

WHERE clause

complexity, 216

DELETE FROM statement, 212–16

one-level SELECT statement, 318,

323

OUTER JOINs and, 350–51

redundancy, 739

scope rules, 216

UPDATE statement, 224–25, 228,

230

Window clause, 714–16

aggregation grouping, 715–16

format, 714

ordering, 715

partitioning, 715

subclauses, 714

WITH CHECK OPTION clause, 383–89

as CHECK() clause, 388–89

CHECK constraint and, 384

defined, 383

updating and, 385

WHERE clause and, 384

WITH clause

derived tables in, 397–99

queries, building, 398

syntax, 397

Words, converting numbers to, 117–

18

X Xbase languages, 171 X/Open transaction model, 757

XOR function, 610

Y Year 2000 problems, 675–80

aftermath, 680 inventory retention programs, 678 leap year, 676–77

legacy data, 679–80 types of, 675 zeros, 675–76

Z Zeller’s algorithm, 666 Zeros, year 2000, 675–76

A B O U T T H E A U T H O R

Joe Celko is a noted consultant and lecturer, and one of the most-read SQL authors in the world He is well known for his 10 years of service on the ANSI SQL standards committee, his column in

Awards), and the war stories he tells to provide real-world insights into SQL programming His best-selling books include Joe Celko’s SQL for Smarties: Advanced SQL Programming, second edition; Joe Celko’s SQL Puzzles and Answers; and Joe Celko’s Trees and Hierarchies

in SQL for Smarties.