build.c

sqlite-3.4.1,嵌入式数据库.是一个功能强大的开源数据库,给学习和研发以及小型公司的发展带来了全所未有的好处.

      sqlite3ErrorMsg(pParse, "no such collation sequence: %.*s", nName, zName);
      pColl = 0;
    }
  }

  return pColl;
}


/*
** Generate code that will increment the schema cookie.
**
** The schema cookie is used to determine when the schema for the
** database changes.  After each schema change, the cookie value
** changes.  When a process first reads the schema it records the
** cookie.  Thereafter, whenever it goes to access the database,
** it checks the cookie to make sure the schema has not changed
** since it was last read.
**
** This plan is not completely bullet-proof.  It is possible for
** the schema to change multiple times and for the cookie to be
** set back to prior value.  But schema changes are infrequent
** and the probability of hitting the same cookie value is only
** 1 chance in 2^32.  So we're safe enough.
*/
void sqlite3ChangeCookie(sqlite3 *db, Vdbe *v, int iDb){
  sqlite3VdbeAddOp(v, OP_Integer, db->aDb[iDb].pSchema->schema_cookie+1, 0);
  sqlite3VdbeAddOp(v, OP_SetCookie, iDb, 0);
}

/*
** Measure the number of characters needed to output the given
** identifier.  The number returned includes any quotes used
** but does not include the null terminator.
**
** The estimate is conservative.  It might be larger that what is
** really needed.
*/
static int identLength(const char *z){
  int n;
  for(n=0; *z; n++, z++){
    if( *z=='"' ){ n++; }
  }
  return n + 2;
}

/*
** Write an identifier onto the end of the given string.  Add
** quote characters as needed.
*/
static void identPut(char *z, int *pIdx, char *zSignedIdent){
  unsigned char *zIdent = (unsigned char*)zSignedIdent;
  int i, j, needQuote;
  i = *pIdx;
  for(j=0; zIdent[j]; j++){
    if( !isalnum(zIdent[j]) && zIdent[j]!='_' ) break;
  }
  needQuote =  zIdent[j]!=0 || isdigit(zIdent[0])
                  || sqlite3KeywordCode(zIdent, j)!=TK_ID;
  if( needQuote ) z[i++] = '"';
  for(j=0; zIdent[j]; j++){
    z[i++] = zIdent[j];
    if( zIdent[j]=='"' ) z[i++] = '"';
  }
  if( needQuote ) z[i++] = '"';
  z[i] = 0;
  *pIdx = i;
}

/*
** Generate a CREATE TABLE statement appropriate for the given
** table.  Memory to hold the text of the statement is obtained
** from sqliteMalloc() and must be freed by the calling function.
*/
static char *createTableStmt(Table *p, int isTemp){
  int i, k, n;
  char *zStmt;
  char *zSep, *zSep2, *zEnd, *z;
  Column *pCol;
  n = 0;
  for(pCol = p->aCol, i=0; i<p->nCol; i++, pCol++){
    n += identLength(pCol->zName);
    z = pCol->zType;
    if( z ){
      n += (strlen(z) + 1);
    }
  }
  n += identLength(p->zName);
  if( n<50 ){
    zSep = "";
    zSep2 = ",";
    zEnd = ")";
  }else{
    zSep = "\n  ";
    zSep2 = ",\n  ";
    zEnd = "\n)";
  }
  n += 35 + 6*p->nCol;
  zStmt = sqliteMallocRaw( n );
  if( zStmt==0 ) return 0;
  sqlite3_snprintf(n, zStmt,
                  !OMIT_TEMPDB&&isTemp ? "CREATE TEMP TABLE ":"CREATE TABLE ");
  k = strlen(zStmt);
  identPut(zStmt, &k, p->zName);
  zStmt[k++] = '(';
  for(pCol=p->aCol, i=0; i<p->nCol; i++, pCol++){
    sqlite3_snprintf(n-k, &zStmt[k], zSep);
    k += strlen(&zStmt[k]);
    zSep = zSep2;
    identPut(zStmt, &k, pCol->zName);
    if( (z = pCol->zType)!=0 ){
      zStmt[k++] = ' ';
      assert( strlen(z)+k+1<=n );
      sqlite3_snprintf(n-k, &zStmt[k], "%s", z);
      k += strlen(z);
    }
  }
  sqlite3_snprintf(n-k, &zStmt[k], "%s", zEnd);
  return zStmt;
}

/*
** This routine is called to report the final ")" that terminates
** a CREATE TABLE statement.
**
** The table structure that other action routines have been building
** is added to the internal hash tables, assuming no errors have
** occurred.
**
** An entry for the table is made in the master table on disk, unless
** this is a temporary table or db->init.busy==1.  When db->init.busy==1
** it means we are reading the sqlite_master table because we just
** connected to the database or because the sqlite_master table has
** recently changed, so the entry for this table already exists in
** the sqlite_master table.  We do not want to create it again.
**
** If the pSelect argument is not NULL, it means that this routine
** was called to create a table generated from a 
** "CREATE TABLE ... AS SELECT ..." statement.  The column names of
** the new table will match the result set of the SELECT.
*/
void sqlite3EndTable(
  Parse *pParse,          /* Parse context */
  Token *pCons,           /* The ',' token after the last column defn. */
  Token *pEnd,            /* The final ')' token in the CREATE TABLE */
  Select *pSelect         /* Select from a "CREATE ... AS SELECT" */
){
  Table *p;
  sqlite3 *db = pParse->db;
  int iDb;

  if( (pEnd==0 && pSelect==0) || pParse->nErr || sqlite3MallocFailed() ) {
    return;
  }
  p = pParse->pNewTable;
  if( p==0 ) return;

  assert( !db->init.busy || !pSelect );

  iDb = sqlite3SchemaToIndex(db, p->pSchema);

#ifndef SQLITE_OMIT_CHECK
  /* Resolve names in all CHECK constraint expressions.
  */
  if( p->pCheck ){
    SrcList sSrc;                   /* Fake SrcList for pParse->pNewTable */
    NameContext sNC;                /* Name context for pParse->pNewTable */

    memset(&sNC, 0, sizeof(sNC));
    memset(&sSrc, 0, sizeof(sSrc));
    sSrc.nSrc = 1;
    sSrc.a[0].zName = p->zName;
    sSrc.a[0].pTab = p;
    sSrc.a[0].iCursor = -1;
    sNC.pParse = pParse;
    sNC.pSrcList = &sSrc;
    sNC.isCheck = 1;
    if( sqlite3ExprResolveNames(&sNC, p->pCheck) ){
      return;
    }
  }
#endif /* !defined(SQLITE_OMIT_CHECK) */

  /* If the db->init.busy is 1 it means we are reading the SQL off the
  ** "sqlite_master" or "sqlite_temp_master" table on the disk.
  ** So do not write to the disk again.  Extract the root page number
  ** for the table from the db->init.newTnum field.  (The page number
  ** should have been put there by the sqliteOpenCb routine.)
  */
  if( db->init.busy ){
    p->tnum = db->init.newTnum;
  }

  /* If not initializing, then create a record for the new table
  ** in the SQLITE_MASTER table of the database.  The record number
  ** for the new table entry should already be on the stack.
  **
  ** If this is a TEMPORARY table, write the entry into the auxiliary
  ** file instead of into the main database file.
  */
  if( !db->init.busy ){
    int n;
    Vdbe *v;
    char *zType;    /* "view" or "table" */
    char *zType2;   /* "VIEW" or "TABLE" */
    char *zStmt;    /* Text of the CREATE TABLE or CREATE VIEW statement */

    v = sqlite3GetVdbe(pParse);
    if( v==0 ) return;

    sqlite3VdbeAddOp(v, OP_Close, 0, 0);

    /* Create the rootpage for the new table and push it onto the stack.
    ** A view has no rootpage, so just push a zero onto the stack for
    ** views.  Initialize zType at the same time.
    */
    if( p->pSelect==0 ){
      /* A regular table */
      zType = "table";
      zType2 = "TABLE";
#ifndef SQLITE_OMIT_VIEW
    }else{
      /* A view */
      zType = "view";
      zType2 = "VIEW";
#endif
    }

    /* If this is a CREATE TABLE xx AS SELECT ..., execute the SELECT
    ** statement to populate the new table. The root-page number for the
    ** new table is on the top of the vdbe stack.
    **
    ** Once the SELECT has been coded by sqlite3Select(), it is in a
    ** suitable state to query for the column names and types to be used
    ** by the new table.
    **
    ** A shared-cache write-lock is not required to write to the new table,
    ** as a schema-lock must have already been obtained to create it. Since
    ** a schema-lock excludes all other database users, the write-lock would
    ** be redundant.
    */
    if( pSelect ){
      Table *pSelTab;
      sqlite3VdbeAddOp(v, OP_Dup, 0, 0);
      sqlite3VdbeAddOp(v, OP_Integer, iDb, 0);
      sqlite3VdbeAddOp(v, OP_OpenWrite, 1, 0);
      pParse->nTab = 2;
      sqlite3Select(pParse, pSelect, SRT_Table, 1, 0, 0, 0, 0);
      sqlite3VdbeAddOp(v, OP_Close, 1, 0);
      if( pParse->nErr==0 ){
        pSelTab = sqlite3ResultSetOfSelect(pParse, 0, pSelect);
        if( pSelTab==0 ) return;
        assert( p->aCol==0 );
        p->nCol = pSelTab->nCol;
        p->aCol = pSelTab->aCol;
        pSelTab->nCol = 0;
        pSelTab->aCol = 0;
        sqlite3DeleteTable(pSelTab);
      }
    }

    /* Compute the complete text of the CREATE statement */
    if( pSelect ){
      zStmt = createTableStmt(p, p->pSchema==pParse->db->aDb[1].pSchema);
    }else{
      n = pEnd->z - pParse->sNameToken.z + 1;
      zStmt = sqlite3MPrintf("CREATE %s %.*s", zType2, n, pParse->sNameToken.z);
    }

    /* A slot for the record has already been allocated in the 
    ** SQLITE_MASTER table.  We just need to update that slot with all
    ** the information we've collected.  The rowid for the preallocated
    ** slot is the 2nd item on the stack.  The top of the stack is the
    ** root page for the new table (or a 0 if this is a view).
    */
    sqlite3NestedParse(pParse,
      "UPDATE %Q.%s "
         "SET type='%s', name=%Q, tbl_name=%Q, rootpage=#0, sql=%Q "
       "WHERE rowid=#1",
      db->aDb[iDb].zName, SCHEMA_TABLE(iDb),
      zType,
      p->zName,
      p->zName,
      zStmt
    );
    sqliteFree(zStmt);
    sqlite3ChangeCookie(db, v, iDb);

#ifndef SQLITE_OMIT_AUTOINCREMENT
    /* Check to see if we need to create an sqlite_sequence table for
    ** keeping track of autoincrement keys.
    */
    if( p->autoInc ){
      Db *pDb = &db->aDb[iDb];
      if( pDb->pSchema->pSeqTab==0 ){
        sqlite3NestedParse(pParse,
          "CREATE TABLE %Q.sqlite_sequence(name,seq)",
          pDb->zName
        );
      }
    }
#endif

    /* Reparse everything to update our internal data structures */
    sqlite3VdbeOp3(v, OP_ParseSchema, iDb, 0,
        sqlite3MPrintf("tbl_name='%q'",p->zName), P3_DYNAMIC);
  }


  /* Add the table to the in-memory representation of the database.
  */
  if( db->init.busy && pParse->nErr==0 ){
    Table *pOld;
    FKey *pFKey; 
    Schema *pSchema = p->pSchema;
    pOld = sqlite3HashInsert(&pSchema->tblHash, p->zName, strlen(p->zName)+1,p);
    if( pOld ){
      assert( p==pOld );  /* Malloc must have failed inside HashInsert() */
      return;
    }
#ifndef SQLITE_OMIT_FOREIGN_KEY
    for(pFKey=p->pFKey; pFKey; pFKey=pFKey->pNextFrom){
      int nTo = strlen(pFKey->zTo) + 1;
      pFKey->pNextTo = sqlite3HashFind(&pSchema->aFKey, pFKey->zTo, nTo);
      sqlite3HashInsert(&pSchema->aFKey, pFKey->zTo, nTo, pFKey);
    }
#endif
    pParse->pNewTable = 0;
    db->nTable++;
    db->flags |= SQLITE_InternChanges;

#ifndef SQLITE_OMIT_ALTERTABLE
    if( !p->pSelect ){
      const char *zName = (const char *)pParse->sNameToken.z;
      int nName;
      assert( !pSelect && pCons && pEnd );
      if( pCons->z==0 ){
        pCons = pEnd;
      }
      nName = (const char *)pCons->z - zName;
      p->addColOffset = 13 + sqlite3Utf8CharLen(zName, nName);
    }
#endif
  }
}

#ifndef SQLITE_OMIT_VIEW
/*
** The parser calls this routine in order to create a new VIEW
*/
void sqlite3CreateView(
  Parse *pParse,     /* The parsing context */
  Token *pBegin,     /* The CREATE token that begins the statement */
  Token *pName1,     /* The token that holds the name of the view */
  Token *pName2,     /* The token that holds the name of the view */
  Select *pSelect,   /* A SELECT statement that will become the new view */
  int isTemp,        /* TRUE for a TEMPORARY view */
  int noErr          /* Suppress error messages if VIEW already exists */
){
  Table *p;
  int n;
  const unsigned char *z;
  Token sEnd;
  DbFixer sFix;
  Token *pName;
  int iDb;

  if( pParse->nVar>0 ){
    sqlite3ErrorMsg(pParse, "parameters are not allowed in views");
    sqlite3SelectDelete(pSelect);
    return;
  }
  sqlite3StartTable(pParse, pName1, pName2, isTemp, 1, 0, noErr);
  p = pParse->pNewTable;
  if( p==0 || pParse->nErr ){
    sqlite3SelectDelete(pSelect);
    return;
  }
  sqlite3TwoPartName(pParse, pName1, pName2, &pName);
  iDb = sqlite3SchemaToIndex(pParse->db, p->pSchema);
  if( sqlite3FixInit(&sFix, pParse, iDb, "view", pName)
    && sqlite3FixSelect(&sFix, pSelect)
  ){
    sqlite3SelectDelete(pSelect);
    return;
  }

  /* Make a copy of the entire SELECT statement that defines the view.
  ** This will force all the Expr.token.z values to be dynamically
  ** allocated rather than point to the input string - which means that
  ** they will persist after the current sqlite3_exec() call returns.
  */
  p->pSelect = sqlite3SelectDup(pSelect);
  sqlite3SelectDelete(pSelect);
  if( sqlite3MallocFailed() ){
    return;
  }
  if( !pParse->db->init.busy ){
    sqlite3ViewGetColumnNames(pParse, p);
  }

  /* Locate the end of the CREATE VIEW statement.  Make sEnd point to
  ** the end.
  */
  sEnd = pParse->sLastToken;
  if( sEnd.z[0]!=0 && sEnd.z[0]!=';' ){
    sEnd.z += sEnd.n;
  }
  sEnd.n = 0;
  n = sEnd.z - pBegin->z;