Question

我有两张桌子＆＃39; table1＆＃39;和＆＃39; table_00＆＃39;。我想将一些数据从table1移到table_00

我有这种方法来做到这一点：

- (void)moveData {


NSString *docsDir;
NSArray *dirPaths;

// Get the documents directory
dirPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
docsDir = dirPaths[0];

// Build the path to the database file

databasePath = [[NSString alloc]
                initWithString: [docsDir stringByAppendingPathComponent:
                                 @"MYDB_3.db"]];

 sqlite3_stmt    *statement;
const char *dbpath = [databasePath UTF8String];

if (sqlite3_open(dbpath, &myDatabase) == SQLITE_OK) {

    NSString *insertSQL=@"INSERT INTO TABLE_00 SELECT * FROM TABLE_1 WHERE ID=00000" ;
     const char *insert_stmt = [insertSQL UTF8String];

    //i am using only one 'insertSQL', i put two 'insertSQL' strings here for reference 
   //mulitple statements
   NSString *insertSQL=@"INSERT INTO TABLE_00 SELECT * FROM TABLE_1 WHERE UTILITYID='00000';"
                         "INSERT INTO TABLE_01 SELECT * FROM TABLE_1 WHERE UTILITYID='00001';"
                         "INSERT INTO TABLE_02 SELECT * FROM TABLE_1 WHERE UTILITYID='00002';"
    "INSERT INTO TABLE_03 SELECT * FROM TABLE_1 WHERE UTILITYID='00003';";

  //this multiple query statement is not working

    sqlite3_prepare_v2(myDatabase, insert_stmt, -1, &statement, NULL);
    if (sqlite3_step(statement) == SQLITE_DONE) {
                   NSLog(@"data moved");
    } else {
        NSLog(@"data not moved");
    }
    sqlite3_finalize(statement);
    sqlite3_close(myDatabase);
}

在我调用此方法后，我可以使用单个查询来移动数据但是，我无法使用多个语句来移动数据。请您告诉我为什么会发生这种情况？

提前致谢。

Answer 1

我认为你有一个额外的，应该是：

INSERT INTO TABLE_00 SELECT * FROM TABLE_1 WHERE ID= '00000'

更好的方法是使用占位符：

sqlite3_stmt *compiled = nil;
const char *sql = "INSERT INTO TABLE_00 SELECT * FROM TABLE_1 WHERE ID= ?";
sqlite3_prepare_v2(database, sql, -1, &compiled, NULL);
sqlite3_bind_text(compiled, 1, [yourId UTF8String], -1, SQLITE_TRANSIENT);
sqlite3_step(compiled);
sqlite3_finalize(compiled);

Answer 2

我使用for循环来执行多个语句。我就是这样做的

- (void)moveDatatoUtilityTables {

NSMutableArray *ID_Table=[[NSMutableArray alloc]init];
NSMutableArray *ID=[[NSMutableArray alloc]init];

[ID_Table addObject:@"TABLE_00"];
[ID_Table addObject:@"TABLE_01"];
[ID_Table addObject:@"TABLE_02"];

[ID addObject:@"00000"];
[ID addObject:@"00001"];
[ID addObject:@"00002"];

NSLog(@"database path is %@",databasePath);

sqlite3_stmt    *statement;
const char *dbpath = [databasePath UTF8String];

if (sqlite3_open(dbpath, &myDatabase) == SQLITE_OK) {

    for (int i=0; i<2; i++) {


        NSString *insertSQL=[NSString stringWithFormat:@" INSERT INTO %@ SELECT * FROM TABLE_1 WHERE ID='%@'",[ID_Table objectAtIndex:i],[ID objectAtIndex:i]];


    const char *insert_stmt = [insertSQL UTF8String];


    sqlite3_prepare_v2(myDatabase, insert_stmt,
                       -1, &statement, NULL);

   // const char *sqlite3_column_name(sqlite3_stmt*, int N);

    if (sqlite3_step(statement) == SQLITE_DONE) {

                   NSLog(@"data moved");


    } else {

        NSLog(@"data not moved");
    }



    sqlite3_finalize(statement);

    }
        sqlite3_close(myDatabase);
}

}

无法在具有多个语句的iOS中的sqlite中将数据从一个表插入另一个表

2 个答案: