SQLite的sqlite3_prepare

original SQL text---<sqlite3_prepare_v2>--->sqlite3_stmt--<sqlite3_reset>-->clear sqlite3_stmt --<sqlite3_bind_*(stmt,1,*)>--> configed sqlite3_stmt

--<sqlite3_step()>--->run sqlite3_stmt---<sqlite3_column_*(statement, N)>--->查询输出----<sqlite3_finalize()>--->释放语句

** CAPI3REF: Prepared Statement Object

** KEYWORDS: {prepared statement} {prepared statements}

** An instance of this object represents a single SQL statement that

** has been compiled into binary form and is ready to be evaluated.

** Think of each SQL statement as a separate computer program. The

** original SQL text is source code. A prepared statement object

** is the compiled object code. All SQL must be converted into a

** prepared statement before it can be run.

** The life-cycle of a prepared statement object usually goes like this:

** <ol>

** <li> Create the prepared statement object using [sqlite3_prepare_v2()].

** <li> Bind values to [parameters] using the sqlite3_bind_*()

** interfaces.

** <li> Run the SQL by calling [sqlite3_step()] one or more times.

** <li> Reset the prepared statement using [sqlite3_reset()] then go back

** to step 2. Do this zero or more times.

** <li> Destroy the object using [sqlite3_finalize()].

** </ol>

-(void)select{

NSString * sqlString = @"select * from person";

//准备sql语句

sqlite3_stmt * stmt = nil;

sqlite3_prepare(db, sqlString.UTF8String, -1, &stmt, nil);

//单步执行语句

while (sqlite3_step(stmt) == SQLITE_ROW) {

const unsigned char * name = sqlite3_column_text(stmt, 0);

NSString * nameStr = [NSString stringWithUTF8String:(const char*)name];

int age = sqlite3_column_int(stmt, 1);

NSLog(@"name:::%@ and age:::%d",nameStr,age);

}

//释放

sqlite3_finalize(stmt);

}

巴特西