Add initial infrastructure for cursors. In where.c, optimize out clauses

of the form "ORDER BY rowid" if a table scan is being performed.  Do a
reverse table scan if "ORDER BY rowid DESC" is present. (CVS 2141)

FossilOrigin-Name: fc8c1393c86017a816beb52725b68af3b973f979

test/alter.test

@@ -1,14 +1,17 @@
+# 2004 November 10
 #
-# The author or author's hereby grant to the public domain a non-exclusive,
-# fully paid-up, perpetual, license in the software and all related
-# intellectual property to make, have made, use, have used, reproduce,
-# prepare derivative works, distribute, perform and display the work.  
+# The author disclaims copyright to this source code.  In place of
+# a legal notice, here is a blessing:
+#
+#    May you do good and not evil.
+#    May you find forgiveness for yourself and forgive others.
+#    May you share freely, never taking more than you give.
 #
 #*************************************************************************
 # This file implements regression tests for SQLite library.  The
 # focus of this script is testing the ALTER TABLE statement.
 #
-# $Id: alter.test,v 1.7 2004/11/22 13:35:42 danielk1977 Exp $
+# $Id: alter.test,v 1.8 2004/11/22 19:12:21 drh Exp $
 #
 
 set testdir [file dirname $argv0]

test/collate4.test

@@ -12,7 +12,7 @@
 # This file implements regression tests for SQLite library.  The
 # focus of this script is page cache subsystem.
 #
-# $Id: collate4.test,v 1.4 2004/11/03 16:27:02 drh Exp $
+# $Id: collate4.test,v 1.5 2004/11/22 19:12:21 drh Exp $
 
 set testdir [file dirname $argv0]
 source $testdir/tester.tcl
@@ -669,6 +669,7 @@ do_test collate4-4.15 {
 # These indices are never used for sorting in SQLite. And you can't
 # create another index on an INTEGER PRIMARY KEY column, so we don't have 
 # to test that.
+# (Revised 2004-Nov-22):  The ROWID can be used for sorting now.
 #
 do_test collate4-6.0 {
   execsql {
@@ -682,12 +683,12 @@ do_test collate4-6.1 {
   cksort {
     SELECT * FROM collate4t1 ORDER BY 1;
   }
-} {10 15 101 sort}
+} {10 15 101 nosort}
 do_test collate4-6.2 {
   cksort {
     SELECT * FROM collate4t1 ORDER BY oid;
   }
-} {10 15 101 sort}
+} {10 15 101 nosort}
 do_test collate4-6.3 {
   cksort {
     SELECT * FROM collate4t1 ORDER BY oid||'' COLLATE TEXT;

test/cursor.test

@@ -0,0 +1,136 @@
+# 2004 November 22
+#
+# The author disclaims copyright to this source code.  In place of
+# a legal notice, here is a blessing:
+#
+#    May you do good and not evil.
+#    May you find forgiveness for yourself and forgive others.
+#    May you share freely, never taking more than you give.
+#
+#*************************************************************************
+# This file implements regression tests for SQLite library.  The
+# focus of this script is DECLARE...CURSOR functionality
+#
+# $Id: cursor.test,v 1.1 2004/11/22 19:12:21 drh Exp $
+#
+
+set testdir [file dirname $argv0]
+source $testdir/tester.tcl
+
+# If SQLITE_OMIT_CURSOR is defined, omit this file.
+ifcapable {!cursor} {
+  finish_test
+  return
+}
+
+########
+# Test the logic that creates and destroys cursors
+########
+do_test cursor-1.1 {
+  execsql {
+    CREATE TABLE t1(a,b,c);
+    CREATE INDEX t1i1 ON t1(a);
+    CREATE INDEX t1i2 ON t1(b,c);
+  }
+  execsql {
+    DECLARE c1 CURSOR FOR SELECT c FROM t1 ORDER BY a;
+  }
+} {}
+ifcapable schema_pragmas {
+  do_test cursor-1.2 {
+    execsql {PRAGMA cursor_list}
+  } {0 c1}
+}
+do_test cursor-1.3 {
+  execsql {
+    DECLARE c2 CURSOR FOR SELECT a FROM t1 ORDER BY b, c;
+  }
+} {}
+ifcapable schema_pragmas {
+  do_test cursor-1.4 {
+    execsql {PRAGMA cursor_list}
+  } {0 c1 1 c2}
+}
+do_test cursor-1.5 {
+  catchsql {
+    CLOSE c3;
+  }
+} {1 {no such cursor: c3}}
+ifcapable schema_pragmas {
+  do_test cursor-1.6 {
+    execsql {PRAGMA cursor_list}
+  } {0 c1 1 c2}
+}
+do_test cursor-1.7 {
+  catchsql {
+    CLOSE c1;
+  }
+} {0 {}}
+ifcapable schema_pragmas {
+  do_test cursor-1.8 {
+    execsql {PRAGMA cursor_list}
+  } {1 c2}
+}
+do_test cursor-1.9 {
+  catchsql {
+    CLOSE c1;
+  }
+} {1 {no such cursor: c1}}
+ifcapable schema_pragmas {
+  do_test cursor-1.10 {
+    execsql {PRAGMA cursor_list}
+  } {1 c2}
+}
+do_test cursor-1.11 {
+  catchsql {
+    DECLARE c2 CURSOR FOR SELECT * FROM t1;
+  }
+} {1 {another cursor named c2 already exists}}
+do_test cursor-1.12 {
+  catchsql {
+    DECLARE c3 CURSOR FOR SELECT * FROM t1;
+  }
+} {0 {}}
+ifcapable schema_pragmas {
+  do_test cursor-1.13 {
+    execsql {PRAGMA cursor_list}
+  } {0 c3 1 c2}
+}
+do_test cursor-1.14 {
+  execsql {
+    CLOSE c2;
+    CLOSE c3;
+  }
+} {}
+ifcapable schema_pragmas {
+  do_test cursor-1.15 {
+    execsql {PRAGMA cursor_list}
+  } {}
+}
+
+set all {}
+for {set i 1} {$i<=50} {incr i} {
+  lappend all [expr {$i-1}] x$i
+  do_test cursor-2.1.$i.1 {
+    execsql "DECLARE x$i CURSOR FOR SELECT * FROM t1"
+  } {}
+  ifcapable schema_pragmas {
+    do_test cursor-2.1.$i.2 {
+      execsql {PRAGMA cursor_list}
+    } $all
+  }
+}
+for {set i 1} {$i<=50} {incr i} {
+  set all [lrange $all 2 end]
+  do_test cursor-2.2.$i.1 {
+    execsql "CLOSE x$i"
+  } {}
+  ifcapable schema_pragmas {
+    do_test cursor-2.2.$i.2 {
+      execsql {PRAGMA cursor_list}
+    } $all
+  }
+}  
+
+
+finish_test

test/where.test

@@ -11,7 +11,7 @@
 # This file implements regression tests for SQLite library.  The
 # focus of this file is testing the use of indices in WHERE clases.
 #
-# $Id: where.test,v 1.23 2004/11/03 16:27:02 drh Exp $
+# $Id: where.test,v 1.24 2004/11/22 19:12:21 drh Exp $
 
 set testdir [file dirname $argv0]
 source $testdir/tester.tcl
@@ -508,6 +508,47 @@ do_test where-6.19 {
     SELECT y FROM t1 ORDER BY w LIMIT 3;
   }
 } {4 9 16 nosort}
+do_test where-6.20 {
+  cksort {
+    SELECT y FROM t1 ORDER BY rowid LIMIT 3;
+  }
+} {4 9 16 nosort}
+do_test where-6.21 {
+  cksort {
+    SELECT y FROM t1 ORDER BY rowid, y LIMIT 3;
+  }
+} {4 9 16 nosort}
+do_test where-6.22 {
+  cksort {
+    SELECT y FROM t1 ORDER BY rowid, y DESC LIMIT 3;
+  }
+} {4 9 16 nosort}
+do_test where-6.23 {
+  cksort {
+    SELECT y FROM t1 WHERE y>4 ORDER BY rowid, w, x LIMIT 3;
+  }
+} {9 16 25 nosort}
+do_test where-6.24 {
+  cksort {
+    SELECT y FROM t1 WHERE y>=9 ORDER BY rowid, x DESC, w LIMIT 3;
+  }
+} {9 16 25 nosort}
+do_test where-6.25 {
+  cksort {
+    SELECT y FROM t1 WHERE y>4 AND y<25 ORDER BY rowid;
+  }
+} {9 16 nosort}
+do_test where-6.26 {
+  cksort {
+    SELECT y FROM t1 WHERE y>=4 AND y<=25 ORDER BY oid;
+  }
+} {4 9 16 25 nosort}
+do_test where-6.27 {
+  cksort {
+    SELECT y FROM t1 WHERE y<=25 ORDER BY _rowid_, w+y;
+  }
+} {4 9 16 25 nosort}
+
 
 # Tests for reverse-order sorting.
 #
@@ -661,6 +702,31 @@ do_test where-7.30 {
     SELECT w FROM t1 WHERE x=6 AND y>=10201 ORDER BY y DESC;
   }
 } {100 nosort}
+do_test where-7.31 {
+  cksort {
+    SELECT y FROM t1 ORDER BY rowid DESC LIMIT 3
+  }
+} {10201 10000 9801 nosort}
+do_test where-7.32 {
+  cksort {
+    SELECT y FROM t1 WHERE y<25 ORDER BY rowid DESC, x
+  }
+} {16 9 4 nosort}
+do_test where-7.33 {
+  cksort {
+    SELECT y FROM t1 WHERE y<=25 ORDER BY rowid DESC, x
+  }
+} {25 16 9 4 nosort}
+do_test where-7.34 {
+  cksort {
+    SELECT y FROM t1 WHERE y<25 AND y>4 ORDER BY rowid DESC, y DESC
+  }
+} {16 9 nosort}
+do_test where-7.35 {
+  cksort {
+    SELECT y FROM t1 WHERE y<25 AND y>=4 ORDER BY rowid DESC
+  }
+} {16 9 4 nosort}
 
 do_test where-8.1 {
   execsql {