System.Data.Tests.DataSetTest.CloneCopy_TestForeignKeyConstraints C# (CSharp) Method

        public void CloneCopy_TestForeignKeyConstraints()
        {
            DataTable dirTable = new DataTable("Directories");

            DataColumn dir_UID = new DataColumn("UID", typeof(int));
            dir_UID.Unique = true;
            dir_UID.AllowDBNull = false;

            dirTable.Columns.Add(dir_UID);

            // Build a simple Files table
            DataTable fileTable = new DataTable("Files");

            DataColumn file_DirID = new DataColumn("DirectoryID", typeof(int));
            file_DirID.Unique = false;
            file_DirID.AllowDBNull = false;

            fileTable.Columns.Add(file_DirID);

            // Build the DataSet
            DataSet ds = new DataSet("TestDataset");
            ds.Tables.Add(dirTable);
            ds.Tables.Add(fileTable);

            // Add a foreign key constraint
            DataColumn[] parentColumns = new DataColumn[1];
            parentColumns[0] = ds.Tables["Directories"].Columns["UID"];

            DataColumn[] childColumns = new DataColumn[1];
            childColumns[0] = ds.Tables["Files"].Columns["DirectoryID"];

            ForeignKeyConstraint fk = new ForeignKeyConstraint("FK_Test", parentColumns, childColumns);
            ds.Tables["Files"].Constraints.Add(fk);
            ds.EnforceConstraints = true;

            Assert.Equal(1, ds.Tables["Directories"].Constraints.Count);
            Assert.Equal(1, ds.Tables["Files"].Constraints.Count);

            // check clone works fine
            DataSet cloned_ds = ds.Clone();
            Assert.Equal(1, cloned_ds.Tables["Directories"].Constraints.Count);
            Assert.Equal(1, cloned_ds.Tables["Files"].Constraints.Count);

            ForeignKeyConstraint clonedFk = (ForeignKeyConstraint)cloned_ds.Tables["Files"].Constraints[0];
            Assert.Equal("FK_Test", clonedFk.ConstraintName);
            Assert.Equal(1, clonedFk.Columns.Length);
            Assert.Equal("DirectoryID", clonedFk.Columns[0].ColumnName);

            UniqueConstraint clonedUc = (UniqueConstraint)cloned_ds.Tables["Directories"].Constraints[0];
            UniqueConstraint origUc = (UniqueConstraint)ds.Tables["Directories"].Constraints[0];
            Assert.Equal(origUc.ConstraintName, clonedUc.ConstraintName);
            Assert.Equal(1, clonedUc.Columns.Length);
            Assert.Equal("UID", clonedUc.Columns[0].ColumnName);

            // check copy works fine
            DataSet copy_ds = ds.Copy();
            Assert.Equal(1, copy_ds.Tables["Directories"].Constraints.Count);
            Assert.Equal(1, copy_ds.Tables["Files"].Constraints.Count);

            ForeignKeyConstraint copyFk = (ForeignKeyConstraint)copy_ds.Tables["Files"].Constraints[0];
            Assert.Equal("FK_Test", copyFk.ConstraintName);
            Assert.Equal(1, copyFk.Columns.Length);
            Assert.Equal("DirectoryID", copyFk.Columns[0].ColumnName);

            UniqueConstraint copyUc = (UniqueConstraint)copy_ds.Tables["Directories"].Constraints[0];
            origUc = (UniqueConstraint)ds.Tables["Directories"].Constraints[0];
            Assert.Equal(origUc.ConstraintName, copyUc.ConstraintName);
            Assert.Equal(1, copyUc.Columns.Length);
            Assert.Equal("UID", copyUc.Columns[0].ColumnName);
        }