How Can Parameterized Queries Solve Data Insertion Issues in Access Databases with Special Characters?

Use parameterized queries to solve the data insertion problem of special characters in Access database

The following code snippet demonstrates inserting data into an Access database using OLE DB data access methods. However, problems arise when inserting text that contains single quotes. Parameterized queries can effectively solve this problem.

Update code with parameters

In order to insert data using parameters, the code needs to be adjusted as follows:

1. Replace hard-coded parameters with placeholders: In the CommandText property of OleDbCommand, replace the actual parameter values ​​with placeholders prefixed with @.
2. Add named OleDbParameters: Create an OleDbParameter instance and add it to the DbCommand.Parameters property. Parameter names must match placeholder names.

The following updated code demonstrates the use of parameters:

<code class="language-csharp">[WebMethod]
public void bookRatedAdd(string title, int rating, string review, string ISBN, string userName)
{
   using (OleDbConnection conn = new OleDbConnection(
         "Provider=Microsoft.Jet.OleDb.4.0;"+
         "Data Source="+Server.MapPath("App_Data\BookRateInitial.mdb"));
   {

      conn.Open();

      // DbCommand 也实现了 IDisposable 接口
      using (OleDbCommand cmd = conn.CreateCommand())
      {
           // 创建带有占位符的命令
           cmd.CommandText = 
              "INSERT INTO bookRated "+
              "([title], [rating],  [review], [frnISBN], [frnUserName]) "+
              "VALUES(@title, @rating, @review, @isbn, @username)";

           // 添加命名参数
           cmd.Parameters.AddRange(new OleDbParameter[]
           {
               new OleDbParameter("@title", title),
               new OleDbParameter("@rating", rating),
               // ... 添加其余参数
           });

           // 执行
           cmd.ExecuteNonQuery();
      }
   }
}</code>

By using parameters, the code ensures that data is inserted safely, preventing potential problems caused by special characters, and maintaining data integrity.

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