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Transaction log - DELETE needs to read records, check constraints, update block, update indexes, and generate redo / undo. All of this takes time, hence it takes time much longer than with TRUNCATE
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Suppose there is a simple database that lists people and addresses. More than one person can live at a particular address and a person can live at more than one address (this is an example of a
527:
table relates the person and address tables, showing that Joe, Bob and Ann all live at 2001 Main Street, but Joe also takes up residence on Pico
Boulevard.
42:
593:. It could be that beyond just having three tables, the database also has been set up with a trigger so that whenever a row is deleted from
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command that works a lot quicker, as it only alters metadata and typically does not spend time enforcing constraints or firing triggers.
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It is a DML (Data
Manipulation Language) command, therefore the following commands are used for this command: COMMIT and ROLLBACK
57:
804:
100:
141:, allow deletion of rows from multiple tables with one DELETE statement (this is sometimes called multi-table DELETE).
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Deletes all or some records from the table, you can limit the records to be deleted by using the WHERE clause
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133:. A subset may be defined for deletion using a condition, otherwise all records are removed. Some
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reduces performance during execution - each record in the table is locked for deletion
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Does not free the space occupied by the data in the table (in the TABLESPACE)
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You can undo the operation of removing records by using the ROLLBACK command
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To maintain referential integrity, Joe's records must be removed from both
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In order to remove joe from the database, two deletes must be executed:
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DELETE generates a small amount of redo and a large amount of undo
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DELETE only deletes the rows. For deleting a table entirely the
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Deleting all rows from a table can be very time-consuming. Some
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DELETE uses more transaction space than the TRUNCATE statement
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DELETE operation does not make unusable indexes usable again
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SQL Routines and Types for the Java
Programming Language
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Does not reset the SEQUENCE value assigned to the table
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statement is used to remove one or more records from a
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697:DELETE can be used in the case of: database link
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19:"DELETE" redirects here. For other uses, see
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779:gives examples of DELETE statements features
700:DELETE returns the number of records deleted
58:introducing citations to additional sources
121:In the database structured query language (
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265:using a subquery in the where condition:
48:Relevant discussion may be found on the
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379:). The database only has three tables,
685:DELETE works much slower than TRUNCATE
597:any linked rows would be deleted from
712:DELETE can be used with indexed views
16:SQL database query language statement
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691:DELETE requires a shared table lock
1098:Information and Definition Schemas
14:
777:Truncate vs Delete SQL Databases
41:relies largely or entirely on a
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1:
601:. Then the first statement:
1088:Management of External Data
391:, with the following data:
371:Example with related tables
135:database management systems
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1108:XML-Related Specifications
395:
18:
1083:Persistent Stored Modules
377:many-to-many relationship
1093:Object Language Bindings
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603:
532:
314:
312:using a list of values:
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244:
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191:'Lemon Meringue'
170:
760:"SQL Delete Statement"
742:command can be used.
238:Delete all rows from
1078:Call-Level Interface
636:trigger the second:
207:is smaller than 80.
54:improve this article
1052:Relational database
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203:, if the value of
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1061:ISO/IEC SQL parts
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308:Delete rows from
261:Delete rows from
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69:"Delete" SQL
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762:. w3schools.com.
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723:Related commands
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199:Delete rows in
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771:External links
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733:TRUNCATE TABLE
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464:35 Pico Blvd.
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456:2001 Main St.
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166:Lemon Meringue
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137:(DBMSs), like
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110:September 2019
52:. Please help
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694:Triggers fire
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634:automatically
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71: –
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66:
65:Find sources:
59:
55:
51:
45:
44:
43:single source
39:This article
37:
33:
28:
27:
22:
1129:SQL keywords
917:
754:
737:
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631:
598:
594:
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448:description
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165:
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126:
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97:
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83:
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64:
40:
153:from table
1073:Foundation
1047:Edgar Codd
746:References
80:newspapers
1068:Framework
50:talk page
1123:Category
1002:Truncate
974:Order by
932:Group by
888:Keywords
878:SQL:2023
873:SQL:2016
868:SQL:2011
863:SQL:2008
858:SQL:2006
853:SQL:2003
848:SQL:1999
821:Versions
731:offer a
668:Features
440:address
300:mytable2
145:Examples
1040:Related
988:Prepare
399:person
385:address
323:mytable
310:mytable
276:mytable
263:mytable
253:mytable
240:mytable
164:equals
149:Delete
125:), the
94:scholar
1016:Update
995:Select
946:Insert
939:Having
918:Delete
911:Create
843:SQL-92
838:SQL-89
833:SQL-86
828:SEQUEL
641:DELETE
632:would
612:person
606:DELETE
595:person
587:person
559:DELETE
541:person
535:DELETE
387:, and
381:person
362:value5
356:value4
350:value3
344:value2
338:value1
317:DELETE
291:SELECT
270:DELETE
247:DELETE
224:height
212:DELETE
205:height
185:flavor
173:DELETE
162:flavor
159:column
157:where
127:DELETE
96:
89:
82:
75:
67:
21:Delete
1023:Where
1009:Union
960:Merge
650:WHERE
615:WHERE
568:WHERE
544:WHERE
407:name
326:WHERE
279:WHERE
221:WHERE
218:trees
201:trees
182:WHERE
139:MySQL
131:table
101:JSTOR
87:books
1030:With
981:Over
967:Null
953:Join
925:From
904:Case
740:DROP
729:DBMS
644:FROM
609:FROM
589:and
562:FROM
538:FROM
523:The
513:200
505:100
497:100
489:100
481:aid
478:pid
445:aid
431:Ann
423:Bob
415:Joe
404:pid
320:FROM
297:FROM
273:FROM
250:FROM
227:<
215:FROM
179:pies
176:FROM
155:pies
151:rows
73:news
814:SQL
653:pid
618:pid
571:pid
547:pid
473:pa
461:200
453:100
123:SQL
56:by
1125::
897:As
647:pa
599:pa
591:pa
565:pa
525:pa
389:pa
383:,
365:);
332:IN
329:id
303:);
294:id
285:IN
282:id
242::
230:80
168::
806:e
799:t
792:v
662:;
659:1
656:=
627:;
624:1
621:=
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577:1
574:=
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553:1
550:=
510:1
502:3
494:2
486:1
428:3
420:2
412:1
359:,
353:,
347:,
341:,
335:(
288:(
256:;
233:;
194:;
188:=
112:)
108:(
98:·
91:·
84:·
77:·
60:.
46:.
23:.
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