WP8/ c# /SQLite:获取最后插入的id
本文关键字:插入 id 最后 SQLite WP8 获取 | 更新日期: 2023-09-27 18:04:22
SQLite with WP8快把我逼疯了。(
我要做的就是检索最后插入的id的值…
我有:
class ShoppingItem
{
[SQLite.PrimaryKey, SQLite.AutoIncrement]
public int Id {get; set;}
public string Name {get; set;}
public string Shop {get; set;}
public bool isActive {get; set;}
}
那么,所使用的SQLiteConnection
对象和它的Table<ShoppingItem>
似乎都不包含包含最后一个ID的合适成员。
所以我试着做:
private int GetLastInsertedRowID()
{
int Result = -1;
using (var db = new SQLiteConnection(m_DatabasePath)) {
Result = db.ExecuteScalar<int>("SELECT last_insert_rowid();");
}
return Result;
}
但是这个函数总是返回0
。:(但是当我读取ShoppingItem
的所有条目时,它们的id值为!= 0。
所以我的问题是:我如何才能检索最后插入的id?
PS:将SQL查询更改为SELECT last_insert_rowid() FROM ShoppingItem;
会得到相同的结果。
PPS:解决方案,如获得最后插入ID与SQLite。. NET在c#中无法编译,显然有一个旧版本的SQLite使用了一个完全不同的API
您的SELECT last_insert_rowid()
调用不起作用,因为您在不同的数据库连接中运行它。
ShoppingItem
对象中读取ID,如下所示:
var si = new ShoppingItem() {
Name = anItem,
Shop = aShop,
isActive = aIsActive,
};
db.Insert(si);
return si.Id;
这是我检索最后插入项的id所做的。提供的代码片段在我使用SQLite 3.7的Windows 8应用程序中工作。XX (SQLite)。
public class ExpenseDataMapper
{
SQLiteConnection connection;
/// <summary>
/// Constructor
/// </summary>
public ExpenseDataMapper()
{
connection = new SQLiteConnection(StaticResources.DATABASE_PATH_NAME);
connection.CreateTable<FinancialListBoxExpenseItem>();
}
/// <summary>
/// Method #1: Inserts an FinancialListBoxExpenseItem into Database
/// </summary>
/// <param name="item"></param>
/// <returns>Primary key of inserted item</returns>
public int insertExpenseItem(FinancialListBoxExpenseItem item)
{
int primaryKey = 0;
connection.RunInTransaction(() =>
{
connection.Insert(item);
primaryKey = item.expenseID;
});
return primaryKey;
}
/// <summary>
/// Method #2: Inserts an FinancialListBoxExpenseItem into Database
/// </summary>
/// <param name="item"></param>
/// <returns>Primary key of inserted item</returns>
public int insertExpenseItem2(FinancialListBoxExpenseItem item)
{
int primaryKey = 0;
connection.RunInTransaction(() =>
{
connection.Insert(item);
primaryKey = connection.ExecuteScalar<int>("SELECT last_insert_rowid()");
});
return primaryKey;
}
}
FinancialListBoxItem类中的id属性如下所示:
public class FinancialListBoxExpenseItem : Money.Common.BindableBase
{
private int _expenseID = 0;
[AutoIncrement, PrimaryKey]
public int expenseID
{
get
{
return _expenseID;
}
set
{
this.SetProperty<int>(ref _expenseID, value);
}
}
}
我建议您为您的pk列'Id'选择一个不同的名称。我不知道Id是不是一个内部关键字。编辑:好吧,它不是一个SQLite关键字,但id不是一个合适的名称(来源:SQLite关键字)
public List<int[]> CreateSymbolByName(string SymbolName, bool AcceptDuplicates)
{
if (! AcceptDuplicates) // check if "AcceptDuplicates" flag is set
{
List<int[]> ExistentSymbols = GetSymbolsByName(SymbolName, 0, 10); // create a list of int arrays with existent records
if (ExistentSymbols.Count > 0) return ExistentSymbols; //(1) return existent records because creation of duplicates is not allowed
}
List<int[]> ResultedSymbols = new List<int[]>(); // prepare a empty list
int[] symbolPosition = { 0, 0, 0, 0 }; // prepare a neutral position for the new symbol
try // If SQL will fail, the code will continue with catch statement
{
//DEFAULT und NULL sind nicht als explizite Identitätswerte zulässig
string commandString = "INSERT INTO [simbs] ([En]) OUTPUT INSERTED.ID VALUES ('" + SymbolName + "') "; // Insert in table "simbs" on column "En" the value stored by variable "SymbolName"
SqlCommand mySqlCommand = new SqlCommand(commandString, SqlServerConnection); // initialize the query environment
SqlDataReader myReader = mySqlCommand.ExecuteReader(); // last inserted ID is recieved as any resultset on the first column of the first row
int LastInsertedId = 0; // this value will be changed if insertion suceede
while (myReader.Read()) // read from resultset
{
if (myReader.GetInt32(0) > -1)
{
int[] symbolID = new int[] { 0, 0, 0, 0 };
LastInsertedId = myReader.GetInt32(0); // (2) GET LAST INSERTED ID
symbolID[0] = LastInsertedId ; // Use of last inserted id
if (symbolID[0] != 0 || symbolID[1] != 0) // if last inserted id succeded
{
ResultedSymbols.Add(symbolID);
}
}
}
myReader.Close();
if (SqlTrace) SQLView.Log(mySqlCommand.CommandText); // Log the text of the command
if (LastInsertedId > 0) // if insertion of the new row in the table was successful
{
string commandString2 = "UPDATE [simbs] SET [IR] = [ID] WHERE [ID] = " + LastInsertedId + " ;"; // update the table by giving to another row the value of the last inserted id
SqlCommand mySqlCommand2 = new SqlCommand(commandString2, SqlServerConnection);
mySqlCommand2.ExecuteNonQuery();
symbolPosition[0] = LastInsertedId; // mark the position of the new inserted symbol
ResultedSymbols.Add(symbolPosition); // add the new record to the results collection
}
}
catch (SqlException retrieveSymbolIndexException) // this is executed only if there were errors in the try block
{
Console.WriteLine("Error: {0}", retrieveSymbolIndexException.ToString()); // user is informed about the error
}
CreateSymbolTable(LastInsertedId); //(3) // Create new table based on the last inserted id
if (MyResultsTrace) SQLView.LogResult(LastInsertedId); // log the action
return ResultedSymbols; // return the list containing this new record
}