我正在尝试编写一个程序,它将表中的特定GUID更改为用户指定的GUID。 问题是当它尝试用新的GUID覆盖旧的GUID时,它会给我以下错误:
您无法添加或更改记录 因为需要相关记录 在表tblEF
中
数据库有5个表。主表tblA的主键设置为pkAccounts。其他表都有一个外键,称为fkAccounts。
所有关系都设置为强制参照完整性和级联删除相关记录。如果我手动打开数据库并编辑关系以获得级联更新相关字段,我的程序将更新GUID但是使用该数据库的程序将不再有效。
为了克服这个问题,我添加了将主键放在主表上的变量,然后在程序完成替换所有GUID后添加主键。在这种情况下,我将在Alter Table中获得语法错误
这是我的代码。对不起,如果它很乱,但这是我的第一个程序之一。加上我第一次搞乱SQL的东西。
try
{
string GetRI = "SELECT fkAccountGUID FROM tblR";
string GetTWI = "SELECT pkAccountGUID FROM tblTW";
string GetAI = "SELECT pkAccountGUID FROM tblA";
string GetEAI = "SELECT fkAccountGUID FROM tblEAI";
string GetEF = "SELECT fkAccountGUID FROM tblEF";
string NoPK = "ALTER TABLE tblA DROP CONSTRAINT pkAID";
string PK = "ALTER TABLE tblA ADD PRIMARY KEY (pkAID)";
DataSet ds = new DataSet();
//create a connection to the database
OleDbConnection ConnectDatabase = new OleDbConnection(
"Provider=Microsoft.Jet.OLEDB.4.0;" +
@"Data Source=C:\db.mdb;" +
"Persist Security Info=True;" +
"Jet OLEDB:Database Password=123;");
//open the connection to the database
ConnectDatabase.Open();
//creates an adapter and runs the string command from the database connection
//it will then fill the information in the dataset in its own table
OleDbDataAdapter DatabaseAdapter = new OleDbDataAdapter(GetRI, ConnectDatabase);
DatabaseAdapter.Fill(ds, "tblR");
OleDbDataAdapter DatabaseAdapter1 = new OleDbDataAdapter(GetAI, ConnectDatabase);
DatabaseAdapter.Fill(ds, "tblA");
OleDbDataAdapter DatabaseAdapter2 = new OleDbDataAdapter(GetTWI, ConnectDatabase);
DatabaseAdapter.Fill(ds, "tblTW");
OleDbDataAdapter DatabaseAdapter3 = new OleDbDataAdapter(GetEAI, ConnectDatabase);
DatabaseAdapter.Fill(ds, "tblEAI");
OleDbDataAdapter DatabaseAdapter4 = new OleDbDataAdapter(GetEF, ConnectDatabase);
DatabaseAdapter.Fill(ds, "tblEF");
//get old GUID
Console.WriteLine("What is the current GUID?");
string OldGUID = Console.ReadLine();
char ap = '\x0027';
OldGUID = ap + OldGUID + ap;
//get new GUID
Console.WriteLine("What is the new GUID name?");
string NewGUID = Console.ReadLine();
NewGUID = ap + NewGUID + ap;
//test lines
//Console.WriteLine(NewGUID);
//Console.WriteLine(OldGUID);
//UPDATE string to rename the old GUID to the New GUID
string UpdateR = "UPDATE tblR SET fkAccountGUID=" + NewGUID + "WHERE fkAccountGUID=" + OldGUID;
string UpdateA = "UPDATE tblA SET pkAccountGUID=" + NewGUID + "WHERE pkAccountGUID=" + OldGUID;
string UpdateTW = "UPDATE tblTW SET pkfkAccountGUID=" + NewGUID + "WHERE pkfkAccountGUID=" + OldGUID;
string UpdateEA = "UPDATE tblTW SET fkAccountGUID=" + NewGUID + "WHERE fkAccountGUID=" + OldGUID;
string UpdateEF = "UPDATE tblEF SET fkAccountGUID=" + NewGUID + "WHERE fkAccountGUID=" + OldGUID;
//create the variables to run the string commands
OleDbCommand updatecmd0 = new OleDbCommand(UpdateF);
OleDbCommand updatecmd1 = new OleDbCommand(UpdateR);
OleDbCommand updatecmd2 = new OleDbCommand(UpdateEA);
OleDbCommand updatecmd3 = new OleDbCommand(UpdateTW);
OleDbCommand updatecmd4 = new OleDbCommand(UpdateA);
OleDbCommand nocheckcmd = new OleDbCommand(NoPK);
OleDbCommand checkcmd = new OleDbCommand(PK);
//have the commands connect to the database
nocheckcmd.Connection = ConnectDatabase;
updatecmd0.Connection = ConnectDatabase;
updatecmd1.Connection = ConnectDatabase;
updatecmd2.Connection = ConnectDatabase;
updatecmd3.Connection = ConnectDatabase;
updatecmd4.Connection = ConnectDatabase;
checkcmd.Connection = ConnectDatabase;
//Run the commands
nocheckcmd.ExecuteNonQuery();
updatecmd0.ExecuteNonQuery();
updatecmd1.ExecuteNonQuery();
updatecmd2.ExecuteNonQuery();
updatecmd3.ExecuteNonQuery();
updatecmd4.ExecuteNonQuery();
checkcmd.ExecuteNonQuery();
//Dispose the adapter and close the connection to the database.
DatabaseAdapter.Dispose();
ConnectDatabase.Close();
//console will display the string if everything completed
Console.WriteLine("Success. Press any key to exit.");
Console.Read();
}
catch (OleDbException Error)
{
//when an error occurs display the error in the console
Console.WriteLine(Error.Message);
Console.Read();
}
基本上,如何编辑5数据库中的GUID字段而不手动打开数据库检查Cascade Update,运行我的程序,然后再次打开数据库并取消选中Cascade Update?
答案 0 :(得分:0)
不是删除约束,只需向表中添加一行并复制数据。
答案 1 :(得分:0)
添加一个名为“UserEnteredGuid”的列,只要值不为null,就会向用户显示该列而不是 real GUID。这真是唯一理智的方法。
通常,主键是永不修改的值。