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);
}