C# 中的 PostgreSQL Npgsql.PostgresException

Question

我对 cmd.ExecuteReader() 有疑问，我得到 Npgsql.PostgresException

    public void connectDB()
    {
        try
        {
            server = "localhost";
            database = "DoveVer3";
            uid = "admin";
            password = "admin";
            string connectionString;
            connectionString = "Host=" + server + ";Username =" + uid + ";" + "PASSWORD=" + password + ";DATABASE=" + database;

            connection.ConnectionString = connectionString;
            connection.Open();

        }
        catch (Exception e)
        {
            MessageBox.Show(e.Message);

        }


    }

我在下面的代码中得到了异常：

  public void AddDoveToDB(Dove dove)
    {
        //add new dove record to tableDB
        connectDB();
        cmd = new NpgsqlCommand();
        cmd.Connection = connection;
        cmd.CommandText = "SELECT * FROM " + DoveTableDB + " WHERE `" + DoveIdColumnDoveTable + "` = '" + dove.GetDoveId() + "'";
        NpgsqlDataReader rdr = cmd.ExecuteReader(); //// <<<<< HERE
        if (rdr.Read() != true)
        {
            rdr.Close();
            cmd.Parameters.Clear();

            cmd.CommandText = "INSERT INTO " + DoveTableDB + "(" + DoveIdColumnDoveTable + "," + DoveIdFatherColumnDoveTable + "," + DoveIdMotherColumnDoveTable + "," + DoveEyesColorColumnDoveTable + "," + DoveFeatherColorDoveTable + "," + DoveImageNameColumnDoveTable + "," + DoveSexColumnDoveTable +") VALUES ('" + dove.GetDoveId() + "','" + dove.GetDoveFatherId() + "','" + dove.GetDoveMotherId() + "','" + dove.GetEyesColor() + "','" + dove.GetFeathersColor()+ "','" + dove.GetImageName() + "','" + dove.GetSex()+ "')";
            cmd.ExecuteNonQuery();

        }
        connection.Close();
    }

我的数据库名为 DoveVer3，我的架构 DoveSchema 是我的 table 代码：

    Name: DoveTable; Type: TABLE; Schema: DoveSchema; Owner: admin
--

CREATE TABLE "DoveTable" (
    "doveId" character varying(20)[] NOT NULL,
    "doveFather" character varying(20)[],
    "doveMother" character varying,
    "doveEyesColor" character varying(20)[],
    "doveFeathersColor" character varying(20)[],
    "doveSex" smallint DEFAULT 3 NOT NULL,
    "imageName" character varying(30)
);
ALTER TABLE "DoveTable" OWNER TO admin;

异常基础消息：

relation "dovetable" don't exist; Statemants: {SELECT * FROM DoveTable WHERE doveId = 'Test'}

Answer 1

默认情况下，所有传递给 PostgreSQL 的标识符都将被视为小写。根据您的创建脚本，您在定义 table 时使用了 quoted-identifer，因此在使用 table.

的名称时需要以下内容

SELECT * FROM "DoveTable"

请注意，它用双引号引起来，并且 'D' 和 'T' 都是大写的。使用带引号的标识符时，您必须始终按照您定义的方式写出它们。

C# 中的 PostgreSQL Npgsql.PostgresException

Postgresql Npgsql.PostgresException in c#

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