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SQLite training in Houston TX on 2019-11-05 (details)
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Overview
Comment:Disallow string constants enclosed in double-quotes within new CREATE TABLE and CREATE INDEX statements. It is still possible to enclose column names in double-quotes, and existing database schemas that use double-quotes for strings can still be loaded. This addresses ticket [9b78184b].
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SHA3-256: 1685610ef8e0dc9218b02461ceab14dc6114f4f5ef7fcda0da395094aff443e1
User & Date: dan 2019-05-20 17:14:25
References
2019-05-20
18:35
A minor variation on check-in [1685610ef8e0dc] which (hopefully) makes the logic a little easier to follow. Also disallows the use of the double-quoted string hack in the query expression used for VACUUM INTO, which is not strictly required, but moves us toward the goal of disallowing the double-quoted string hack everywhere. check-in: 3e1b55f3 user: drh tags: trunk
17:15 Closed ticket [9b78184b]: Index on non-existing column results in a fabricated value being fetched plus 6 other changes artifact: 6093aca9 user: dan
Context
2019-05-20
18:35
A minor variation on check-in [1685610ef8e0dc] which (hopefully) makes the logic a little easier to follow. Also disallows the use of the double-quoted string hack in the query expression used for VACUUM INTO, which is not strictly required, but moves us toward the goal of disallowing the double-quoted string hack everywhere. check-in: 3e1b55f3 user: drh tags: trunk
17:14
Disallow string constants enclosed in double-quotes within new CREATE TABLE and CREATE INDEX statements. It is still possible to enclose column names in double-quotes, and existing database schemas that use double-quotes for strings can still be loaded. This addresses ticket [9b78184b]. check-in: 1685610e user: dan tags: trunk
10:36
Update the sqlite3ExprCompare() routine so that it does not think "? IS NOT TRUE" is the same as "? IS TRUE". Fix for [d3e7f2ba5b3]. check-in: 99eba69b user: dan tags: trunk
Changes
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Changes to src/resolve.c.

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  ** pExpr.
  **
  ** Because no reference was made to outer contexts, the pNC->nRef
  ** fields are not changed in any context.
  */
  if( cnt==0 && zTab==0 ){
    assert( pExpr->op==TK_ID );
    if( ExprHasProperty(pExpr,EP_DblQuoted) ){


      /* If a double-quoted identifier does not match any known column name,
      ** then treat it as a string.
      **
      ** This hack was added in the early days of SQLite in a misguided attempt
      ** to be compatible with MySQL 3.x, which used double-quotes for strings.
      ** I now sorely regret putting in this hack. The effect of this hack is
      ** that misspelled identifier names are silently converted into strings
................................................................................
** An error message is left in pParse if anything is amiss.  The number
** if errors is returned.
*/
int sqlite3ResolveExprNames( 
  NameContext *pNC,       /* Namespace to resolve expressions in. */
  Expr *pExpr             /* The expression to be analyzed. */
){
  u16 savedHasAgg;
  Walker w;

  if( pExpr==0 ) return SQLITE_OK;
  savedHasAgg = pNC->ncFlags & (NC_HasAgg|NC_MinMaxAgg|NC_HasWin);
  pNC->ncFlags &= ~(NC_HasAgg|NC_MinMaxAgg|NC_HasWin);
  w.pParse = pNC->pParse;
  w.xExprCallback = resolveExprStep;
................................................................................
    sSrc.a[0].zName = pTab->zName;
    sSrc.a[0].pTab = pTab;
    sSrc.a[0].iCursor = -1;
  }
  sNC.pParse = pParse;
  sNC.pSrcList = &sSrc;
  sNC.ncFlags = type;



  if( (rc = sqlite3ResolveExprNames(&sNC, pExpr))!=SQLITE_OK ) return rc;
  if( pList ) rc = sqlite3ResolveExprListNames(&sNC, pList);
  return rc;
}







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  ** pExpr.
  **
  ** Because no reference was made to outer contexts, the pNC->nRef
  ** fields are not changed in any context.
  */
  if( cnt==0 && zTab==0 ){
    assert( pExpr->op==TK_ID );
    if( ExprHasProperty(pExpr,EP_DblQuoted) 
     && 0==(pTopNC->ncFlags&NC_NewSchema) 
    ){
      /* If a double-quoted identifier does not match any known column name,
      ** then treat it as a string.
      **
      ** This hack was added in the early days of SQLite in a misguided attempt
      ** to be compatible with MySQL 3.x, which used double-quotes for strings.
      ** I now sorely regret putting in this hack. The effect of this hack is
      ** that misspelled identifier names are silently converted into strings
................................................................................
** An error message is left in pParse if anything is amiss.  The number
** if errors is returned.
*/
int sqlite3ResolveExprNames( 
  NameContext *pNC,       /* Namespace to resolve expressions in. */
  Expr *pExpr             /* The expression to be analyzed. */
){
  int savedHasAgg;
  Walker w;

  if( pExpr==0 ) return SQLITE_OK;
  savedHasAgg = pNC->ncFlags & (NC_HasAgg|NC_MinMaxAgg|NC_HasWin);
  pNC->ncFlags &= ~(NC_HasAgg|NC_MinMaxAgg|NC_HasWin);
  w.pParse = pNC->pParse;
  w.xExprCallback = resolveExprStep;
................................................................................
    sSrc.a[0].zName = pTab->zName;
    sSrc.a[0].pTab = pTab;
    sSrc.a[0].iCursor = -1;
  }
  sNC.pParse = pParse;
  sNC.pSrcList = &sSrc;
  sNC.ncFlags = type;
  if( pTab && !pParse->db->init.busy && !sqlite3WritableSchema(pParse->db) ){
    sNC.ncFlags |= NC_NewSchema;
  }
  if( (rc = sqlite3ResolveExprNames(&sNC, pExpr))!=SQLITE_OK ) return rc;
  if( pList ) rc = sqlite3ResolveExprListNames(&sNC, pList);
  return rc;
}

Changes to src/sqliteInt.h.

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    ExprList *pEList;    /* Optional list of result-set columns */
    AggInfo *pAggInfo;   /* Information about aggregates at this level */
    Upsert *pUpsert;     /* ON CONFLICT clause information from an upsert */
  } uNC;
  NameContext *pNext;  /* Next outer name context.  NULL for outermost */
  int nRef;            /* Number of names resolved by this context */
  int nErr;            /* Number of errors encountered while resolving names */
  u16 ncFlags;         /* Zero or more NC_* flags defined below */
  Select *pWinSelect;  /* SELECT statement for any window functions */
};

/*
** Allowed values for the NameContext, ncFlags field.
**
** Value constraints (all checked via assert()):
................................................................................
#define NC_UEList    0x0080  /* True if uNC.pEList is used */
#define NC_UAggInfo  0x0100  /* True if uNC.pAggInfo is used */
#define NC_UUpsert   0x0200  /* True if uNC.pUpsert is used */
#define NC_MinMaxAgg 0x1000  /* min/max aggregates seen.  See note above */
#define NC_Complex   0x2000  /* True if a function or subquery seen */
#define NC_AllowWin  0x4000  /* Window functions are allowed here */
#define NC_HasWin    0x8000  /* One or more window functions seen */


/*
** An instance of the following object describes a single ON CONFLICT
** clause in an upsert.
**
** The pUpsertTarget field is only set if the ON CONFLICT clause includes
** conflict-target clause.  (In "ON CONFLICT(a,b)" the "(a,b)" is the







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    ExprList *pEList;    /* Optional list of result-set columns */
    AggInfo *pAggInfo;   /* Information about aggregates at this level */
    Upsert *pUpsert;     /* ON CONFLICT clause information from an upsert */
  } uNC;
  NameContext *pNext;  /* Next outer name context.  NULL for outermost */
  int nRef;            /* Number of names resolved by this context */
  int nErr;            /* Number of errors encountered while resolving names */
  int ncFlags;         /* Zero or more NC_* flags defined below */
  Select *pWinSelect;  /* SELECT statement for any window functions */
};

/*
** Allowed values for the NameContext, ncFlags field.
**
** Value constraints (all checked via assert()):
................................................................................
#define NC_UEList    0x0080  /* True if uNC.pEList is used */
#define NC_UAggInfo  0x0100  /* True if uNC.pAggInfo is used */
#define NC_UUpsert   0x0200  /* True if uNC.pUpsert is used */
#define NC_MinMaxAgg 0x1000  /* min/max aggregates seen.  See note above */
#define NC_Complex   0x2000  /* True if a function or subquery seen */
#define NC_AllowWin  0x4000  /* Window functions are allowed here */
#define NC_HasWin    0x8000  /* One or more window functions seen */
#define NC_NewSchema 0x10000 /* Currently resolving self-refs for new object */

/*
** An instance of the following object describes a single ON CONFLICT
** clause in an upsert.
**
** The pUpsertTarget field is only set if the ON CONFLICT clause includes
** conflict-target clause.  (In "ON CONFLICT(a,b)" the "(a,b)" is the

Changes to test/check.test.

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  execsql {
    SELECT * FROM t1;
  }
} {4 11.0}

do_test check-2.1 {
  execsql {

    CREATE TABLE t2(
      x INTEGER CONSTRAINT one CHECK( typeof(coalesce(x,0))=="integer" ),
      y REAL CONSTRAINT two CHECK( typeof(coalesce(y,0.1))=='real' ),
      z TEXT CONSTRAINT three CHECK( typeof(coalesce(z,''))=='text' )
    );

  }
} {}
do_test check-2.2 {
  execsql {
    INSERT INTO t2 VALUES(1,2.2,'three');
    SELECT * FROM t2;
  }







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  execsql {
    SELECT * FROM t1;
  }
} {4 11.0}

do_test check-2.1 {
  execsql {
    PRAGMA writable_schema = 1;
    CREATE TABLE t2(
      x INTEGER CONSTRAINT one CHECK( typeof(coalesce(x,0))=="integer" ),
      y REAL CONSTRAINT two CHECK( typeof(coalesce(y,0.1))=='real' ),
      z TEXT CONSTRAINT three CHECK( typeof(coalesce(z,''))=='text' )
    );
    PRAGMA writable_schema = 0;
  }
} {}
do_test check-2.2 {
  execsql {
    INSERT INTO t2 VALUES(1,2.2,'three');
    SELECT * FROM t2;
  }

Changes to test/quote.test.

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# focus of this file is the ability to specify table and column names
# as quoted strings.
#
# $Id: quote.test,v 1.7 2007/04/25 11:32:30 drh Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl


# Create a table with a strange name and with strange column names.
#
do_test quote-1.0 {
  catchsql {CREATE TABLE '@abc' ( '#xyz' int, '!pqr' text );}
} {0 {}}

................................................................................
#
do_test quote-1.6 {
  set r [catch {
    execsql {DROP TABLE '@abc'}
  } msg ]
  lappend r $msg
} {0 {}}
 





















































finish_test







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# focus of this file is the ability to specify table and column names
# as quoted strings.
#
# $Id: quote.test,v 1.7 2007/04/25 11:32:30 drh Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl
set testprefix quote

# Create a table with a strange name and with strange column names.
#
do_test quote-1.0 {
  catchsql {CREATE TABLE '@abc' ( '#xyz' int, '!pqr' text );}
} {0 {}}

................................................................................
#
do_test quote-1.6 {
  set r [catch {
    execsql {DROP TABLE '@abc'}
  } msg ]
  lappend r $msg
} {0 {}}

#-------------------------------------------------------------------------
# Check that it is not possible to use double-quotes for a string
# constant in a CHECK constraint or CREATE INDEX statement. However, 
# SQLite can load such a schema from disk.
#
reset_db 
do_execsql_test 2.0 {
  CREATE TABLE t1(x, y, z);
}
foreach {tn sql errname} {
  1 { CREATE TABLE xyz(a, b, c CHECK (c!="null") ) } null
  2 { CREATE INDEX i2 ON t1(x, y, z||"abc") }        abc
  3 { CREATE INDEX i3 ON t1("w") }                   w
  4 { CREATE INDEX i4 ON t1(x) WHERE z="w" }         w
} {
  do_catchsql_test 2.1.$tn $sql [list 1 "no such column: $errname"]
}

do_execsql_test 2.2 {
  PRAGMA writable_schema = 1;
  CREATE TABLE xyz(a, b, c CHECK (c!="null") );
  CREATE INDEX i2 ON t1(x, y, z||"abc");
  CREATE INDEX i3 ON t1("w");
  CREATE INDEX i4 ON t1(x) WHERE z="w";
}

db close
sqlite3 db test.db

do_execsql_test 2.3.1 {
  INSERT INTO xyz VALUES(1, 2, 3);
}
do_catchsql_test 2.3.2 {
  INSERT INTO xyz VALUES(1, 2, 'null');
} {1 {CHECK constraint failed: xyz}}

do_execsql_test 2.4 {
  INSERT INTO t1 VALUES(1, 2, 3);
  INSERT INTO t1 VALUES(4, 5, 'w');
  SELECT * FROM t1 WHERE z='w';
} {4 5 w}
do_execsql_test 2.5 {
  SELECT sql FROM sqlite_master;
} {
  {CREATE TABLE t1(x, y, z)}
  {CREATE TABLE xyz(a, b, c CHECK (c!="null") )}
  {CREATE INDEX i2 ON t1(x, y, z||"abc")}
  {CREATE INDEX i3 ON t1("w")}
  {CREATE INDEX i4 ON t1(x) WHERE z="w"}
}



finish_test