ios - 打开两个sqlite数据库并在iphone中执行查询

Question

这里我想使用两个数据库执行查询并将数据从数据库 1 的表复制到另一个数据库 2。在这里我可以打开一个数据库，但在打开其他数据库时遇到问题。在此先感谢大家。

CurrentStatus *status = [CurrentStatus sharedCurrentStatus];
    sqlite3 *database;
    sqlite3 *database1;
    sqlite3_stmt *statement;
    sqlite3_stmt *statement1;
    NSString *dbPath = [status.applicationDocumentDirectory stringByAppendingPathComponent:@"database.sqlite"];
    NSString *dbPath1 = [status.applicationDocumentDirectory stringByAppendingPathComponent:@"database1.sqlite"];

    if ((sqlite3_open_v2([dbPath UTF8String], &database, SQLITE_OPEN_READWRITE , NULL) == SQLITE_OK) && (sqlite3_open_v2([dbPath1 UTF8String], &database1, SQLITE_OPEN_READWRITE , NULL) == SQLITE_OK)) {

        NSString *sqlStr = [[NSString alloc] initWithFormat:@"select * from Login" ];
         NSString *sql = [[NSString alloc] initWithString:sqlStr];

                if ((sqlite3_prepare_v2(database, [sql UTF8String], -1, &statement, NULL) == SQLITE_OK)) {
                    NSLog(@"DB prepare_v2 Opening successfully");
                    if (sqlite3_step(statement) == SQLITE_ROW) {

                    }
                    else
                    {

                    }
                    sqlite3_finalize(statement);
        NSLog(@"DB Opening successfully");

               sqlite3_close(database);
    }else
    {
        NSLog(@"else DB Opening successfully");
    }
        sqlite3_close(database);
    }

Answer 1

尝试类似的事情来完成你的任务..

首先，您打开“DB1”数据库，然后执行以下语句:

ATTACH DATABASE "2ndDB.db" AS 2ndDB;

之后，您可以使用 CREATE TABLE 语法:

CREATE TABLE newTableInDB1 AS SELECT * FROM 2ndDB.oldTableInMyOtherDB;

这会将数据“复制”到您的新数据库