SQLite

  u8 inTrans;          /* 0: not writable.  1: Transaction.  2: Checkpoint */
  u8 safety_level;     /* How aggressive at syncing data to disk */
  Schema *pSchema;     /* Pointer to database schema (possibly shared) */
};

/*
** An instance of the following structure stores a database schema.
**
** If there are no virtual tables configured in this schema, the
** Schema.db variable is set to NULL. After the first virtual table
** has been added, it is set to point to the database connection 
** used to create the connection. Once a virtual table has been
** added to the Schema structure and the Schema.db variable populated, 
** only that database connection may use the Schema to prepare 
** statements.
*/
struct Schema {
  int schema_cookie;   /* Database schema version number for this file */
  Hash tblHash;        /* All tables indexed by name */
  Hash idxHash;        /* All (named) indices indexed by name */
  Hash trigHash;       /* All triggers indexed by name */
  Hash fkeyHash;       /* All foreign keys by referenced table name */
  Table *pSeqTab;      /* The sqlite_sequence table used by AUTOINCREMENT */
  u8 file_format;      /* Schema format version for this file */
  u8 enc;              /* Text encoding used by this database */
  u16 flags;           /* Flags associated with this schema */
  int cache_size;      /* Number of pages to use in the cache */
#ifndef SQLITE_OMIT_VIRTUALTABLE
  sqlite3 *db;         /* "Owner" connection. See comment above */
#endif
};

/*
** These macros can be used to test, set, or clear bits in the 
** Db.pSchema->flags field.
*/
#define DbHasProperty(D,I,P)     (((D)->aDb[I].pSchema->flags&(P))==(P))

    int nName = sqlite3Strlen30(zName);
    pOld = sqlite3HashInsert(&pSchema->tblHash, zName, nName, pTab);
    if( pOld ){
      db->mallocFailed = 1;
      assert( pTab==pOld );  /* Malloc must have failed inside HashInsert() */
      return;
    }
    pSchema->db = pParse->db;
    pParse->pNewTable = 0;
  }
}

/*
** The parser calls this routine when it sees the first token
** of an argument to the module name in a CREATE VIRTUAL TABLE statement.