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Overview
Comment:Updates to the "Distinctive Features" document. (CVS 3530)
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SHA1: c734585e1a801bec2d393d000c323ba842c2292d
User & Date: drh 2006-12-18 14:12:21.000
Context
2006-12-18
18:34
Speed improvement: do not journal or rollback pages that are pulled out of the freelist. (CVS 3531) (check-in: 4dffc4c3c9 user: drh tags: trunk)
14:12
Updates to the "Distinctive Features" document. (CVS 3530) (check-in: c734585e1a user: drh tags: trunk)
2006-12-16
16:25
Query optimizer enhancement: In "FROM a,b,c left join d" allow the C table to be reordered with A and B. This used to be the case but the capability was removed by (3203) and (3052) in response to ticket #1652. This change restores the capability. (CVS 3529) (check-in: 7393c81b8c user: drh tags: trunk)
Changes
Unified Diff Ignore Whitespace Patch
Changes to www/different.tcl. 
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set rcsid {$Id: different.tcl,v 1.7 2006/05/11 13:33:15 drh Exp $}
source common.tcl
header {Distinctive Features Of SQLite}
puts {
<p>
This page highlights some of the characteristics of SQLite that are
unusual and which make SQLite different from many other SQL
database engines.

|








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set rcsid {$Id: different.tcl,v 1.8 2006/12/18 14:12:21 drh Exp $}
source common.tcl
header {Distinctive Features Of SQLite}
puts {
<p>
This page highlights some of the characteristics of SQLite that are
unusual and which make SQLite different from many other SQL
database engines.
︙︙
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  of the column in which the value is stored.
  SQLite thus allows the user to store
  any value of any datatype into any column regardless of the declared type
  of that column.  (There are some exceptions to this rule: An INTEGER
  PRIMARY KEY column may only store integers.  And SQLite attempts to coerce
  values into the declared datatype of the column when it can.)
  <p>
  The SQL language specification calls for static typing.  So some people


  feel that the use of manifest typing is a bug in SQLite.  But the authors
  of SQLite feel very strongly that this is a feature.  The authors argue
  that static typing is a bug in the SQL specification that SQLite has fixed
  in a backwards compatible way.



}

feature flex {Variable-length records} {
  Most other SQL database engines allocated a fixed amount of disk space
  for each row in most tables.  They play special tricks for handling
  BLOBs and CLOBs which can be of wildly varying length.  But for most
  tables, if you declare a column to be a VARCHAR(100) then the database








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  of the column in which the value is stored.
  SQLite thus allows the user to store
  any value of any datatype into any column regardless of the declared type
  of that column.  (There are some exceptions to this rule: An INTEGER
  PRIMARY KEY column may only store integers.  And SQLite attempts to coerce
  values into the declared datatype of the column when it can.)
  <p>
  As far as we can tell, the SQL language specification allows the use
  of manifest typing.   Nevertheless, most other SQL database engines are
  statically typed and so some people
  feel that the use of manifest typing is a bug in SQLite.  But the authors
  of SQLite feel very strongly that this is a feature.  The use of manifest
  typing in SQLite is a deliberate design decision which has proven in practice

  to make SQLite more reliable and easier to use, especially when used in
  combination with dynamically typed programming languages such as Tcl and
  Python.
}

feature flex {Variable-length records} {
  Most other SQL database engines allocated a fixed amount of disk space
  for each row in most tables.  They play special tricks for handling
  BLOBs and CLOBs which can be of wildly varying length.  But for most
  tables, if you declare a column to be a VARCHAR(100) then the database
︙︙