SQLite的sqlite3_prepare_v2

原文链接： http://www.cnblogs.com/feng9exe/p/10685312.html

 original SQL text------>sqlite3_stmt---->clear sqlite3_stmt ----> configed sqlite3_stmt

----->run sqlite3_stmt---)>--->查询输出------->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:

**

**

**

1. Create the prepared statement object using [sqlite3_prepare_v2()].

   **

2. Bind values to [parameters] using the sqlite3_bind_*()

   **      interfaces.

   **

3. Run the SQL by calling [sqlite3_step()] one or more times.

   **

4. Reset the prepared statement using [sqlite3_reset()] then go back

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

   **

5. Destroy the object using [sqlite3_finalize()].

   **

 

 

-(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);

    

}

 

转载于:https://www.cnblogs.com/feng9exe/p/10685312.html