c# winform问题 datetable如何的每一个列怎么增加约束

DataTable dt = new DataTable();
DataColumn dc0 = new DataColumn("c0", Type.GetType("System.Int32"));
dt.Columns.Add(dc0);
// 主键
dt.PrimaryKey = new DataColumn[] { dc0 };
// 自动索引编号(起始值为1,步增长量为1)
dc0.AutoIncrement = true;
dc0.AutoIncrementStep = 1;
dc0.AutoIncrementSeed = 1;

DataColumn dc1 = new DataColumn("c1", Type.GetType("System.String"));
// default约束
dc1.DefaultValue = "默认值";
dt.Columns.Add(dc1);

DataColumn dc2 = new DataColumn("c2", Type.GetType("System.String"));
// unique约束
dc2.Unique = true;
dt.Columns.Add(dc2);

DataColumn dc3 = new DataColumn("c3", Type.GetType("System.Int32"));
// 是否可以为空
dc2.AllowDBNull = false;
// 限制列C3中只能输入大于等于50的值
dc2.Expression = "c3 >= 50";
dt.Columns.Add(dc2);