[iPhone-Sqlite3]sqlite3_prepare_v2() 不返回 SQLITE_OK，调试

这是关于这个整形的定义。

#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 /* NOT USED. Table or record not found */

#define SQLITE_FULL 13 /* Insertion failed because database is full */

#define SQLITE_CANTOPEN 14 /* Unable to open the database file */

#define SQLITE_PROTOCOL 15 /* NOT USED. 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 */

当调用 sqlite3_prepare_v2() 函数的时候，是一个将SQL语句编译为sqlite内部一个结构体(sqlite3_stmt).

该结构体中包含了将要执行的的SQL语句的信息.

通常情况下，应该是返回0。还有一些时候是返回其他数值。

我以1为例，简单介绍一下错误解决的思路和方法：

#define SQLITE_ERROR 1 /* SQL error or missing database */

我们尝试用以下代码来进行测试：

// Get the path to the documents directory and append the databaseName

NSString *documentPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);

NSString *documentsDir = [documentPaths objectAtIndex:0];

databasePath = [documentsDir stringByAppendingPathComponent:databaseName];

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);

NSString *documentsDirectory = [paths objectAtIndex:0];

NSString *path = [documentsDirectory stringByAppendingPathComponent:databaseName];

NSFileManager *fileManager = [NSFileManager defaultManager];

上面的这个path，我们可以看到，我们需要连接的数据库的那个路径。有时候，如果你的工程创建好了以后，在运行时会把database复制到这个路径下面。如果中途数据库发生了变化，随之有可能没有拷贝过去，那么这个路径下的数据库文件会和你工程里面的不一致。也许这个path下面的是一个大小为0字节的空数据库。所以通常即便是发现了数据库的存在，但是也不能保证你数据库的结构体是正确的。

BOOL find = [fileManager fileExistsAtPath:path];

if (find) {

NSLog(@"Database file have already existed.");

if(sqlite3_open([path UTF8String], &database_) != SQLITE_OK) {

sqlite3_close(database_);

NSLog(@"Error: open database file.");

return NO;

}

return YES;

}

else {

sqlite3_close(database_);

NSLog(@"Error: open database file.");

return NO;

}

上面是打开的代码。下一篇，我将要分享一下如何购建一个SqliteHelper类及其方法。
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