返回值我们用来判断是否执行成功。sqlite 中帮我们定义了一系列的宏，用来作为返回值：

#define sqlITE_OK           0   /* Successful result */
/* beginning-of-error-codes */
#define sqlITE_ERROR        1   /* sql error or missing database */
#define sqlITE_INTERNAL     2   /* Internal logic error in sqlite */
#define sqlITE_PERM         3   /* Access permission denied */
#define sqlITE_ABORT        4   /* Callback routine requested an abort */
#define sqlITE_BUSY         5   /* The database file is locked */
#define sqlITE_LOCKED       6   /* A table in the database is locked */
#define sqlITE_NOMEM        7   /* A malloc() Failed */
#define sqlITE_READONLY     8   /* Attempt to write a readonly database */
#define sqlITE_INTERRUPT    9   /* Operation terminated by sqlite3_interrupt()*/
#define sqlITE_IOERR       10   /* Some kind of disk I/O error occurred */
#define sqlITE_CORRUPT     11   /* The database disk image is malformed */
#define sqlITE_NOTFOUND    12   /* Unknown opcode in sqlite3_file_control() */
#define sqlITE_FULL        13   /* Insertion Failed because database is full */
#define sqlITE_CANTOPEN    14   /* Unable to open the database file */
#define sqlITE_PROTOCOL    15   /* Database lock protocol error */
#define sqlITE_EMPTY       16   /* Database is empty */
#define sqlITE_SCHEMA      17   /* The database schema changed */
#define sqlITE_TOOBIG      18   /* String or BLOB exceeds size limit */
#define sqlITE_CONSTRAINT  19   /* Abort due to constraint violation */
#define sqlITE_MISMATCH    20   /* Data type mismatch */
#define sqlITE_MISUSE      21   /* Library used incorrectly */
#define sqlITE_NOLFS       22   /* Uses OS features not supported on host */
#define sqlITE_AUTH        23   /* Authorization denied */
#define sqlITE_FORMAT      24   /* Auxiliary database format error */
#define sqlITE_RANGE       25   /* 2nd parameter to sqlite3_bind out of range */
#define sqlITE_NOTADB      26   /* File opened that is not a database file */
#define sqlITE_ROW         100  /* sqlite3_step() has another row ready */
#define sqlITE_DONE        101  /* sqlite3_step() has finished executing */
/* end-of-error-codes */