Question

我想在Yii2中通过迁移添加一个新列，使用以下代码：

public function up()
{
    $this->addColumn('news', 'priority', $this->integer());
}

public function down()
{
    $this->dropColumn('news', 'priority');
}

它有效，但我希望它在名字之后成为第二列。

有可能吗？

Answer 1

好的，你可以试试这个：

public class OracleContext : DbContext
{
    public virtual DbSet<Parent> Parents { get; set; }
    public virtual DbSet<Child> Children { get; set; }
    public virtual DbSet<Reference> References { get; set; }
    public virtual DbSet<SomethingElse> SomethingElses { get; set; }
}

public class Parent
{
    [Key, MaxLength(30)]
    public string Name { get; set; }

    [InverseProperty("Parent")]
    public virtual List<Child> Children { get; set; } = new List<Child>();
}

public class Child
{
    [Key, Column(Order = 1), MaxLength(30)]
    public string Parent_Name { get; set; }

    [Key, Column(Order = 2), MaxLength(30)]
    public string Name { get; set; }

    public string Reference_Name { get; set; }

    [ForeignKey("Parent_Name")]
    public virtual Parent Parent { get; set; }

    [ForeignKey("Reference_Name")]
    public virtual Reference Reference { get; set; }

    public Child Clone()
    {
        return new Child
        {
            Parent_Name = this.Parent_Name,
            Name = this.Name,
            Reference_Name = this.Reference_Name,
            Parent = this.Parent,
            Reference = this.Reference
        };
    }
}

public class Reference
{
    [Key, MaxLength(30)]
    public string Name { get; set; }
}

public class SomethingElse
{
    [Key, MaxLength(30)]
    public string Name { get; set; }
}

private void button1_Click(object sender, EventArgs e)
{
    OracleContext context = new OracleContext();

    Reference reference = context.References.Add(new Reference { Name = "Reference" });

    Parent alpha = context.Parents.Add(new Parent { Name = "Alpha" });

    Child alphaOne = new Child { Name = "AlphaOne" };
    Child alphatwo = new Child { Name = "AlphaTwo", Reference_Name = "Reference" };
    alpha.Children.AddRange(new List<Child> { alphaOne, alphatwo });
    alphaOne.Reference = reference;

    var list = (
            from child in alpha.Children
            select new
            {
                Time = "Before referencing SomethingElses.Local",
                Child = child.Clone()
            }
        ).ToList();

    var x = context.SomethingElses.Local;

    list.AddRange(
            from child in alpha.Children
            select new
            {
                Time = "After referencing SomethingElses.Local",
                Child = child.Clone()
            }
        );

    list.AddRange(
            from parent in context.Parents.Local
            from child in parent.Children
            select new
            {
                Time = "Before SaveChanges",
                Child = child.Clone()
            }
        );

    context.SaveChanges();

    list.AddRange(
            from parent in context.Parents.Local
            from child in parent.Children
            select new
            {
                Time = "After SaveChanges",
                Child = child.Clone()
            }
        );

    foreach (var item in list)
    {
        Console.WriteLine("{0}:\r\n\tName = '{1}'\r\n\tParent = '{2}' ({3})\r\n\tReference = '{4}' ({5})",
            item.Time, item.Child.Name, item.Child.Parent_Name, item.Child.Parent, item.Child.Reference_Name, item.Child.Reference);
    }
}

Before referencing SomethingElses.Local:
    Name = 'AlphaOne'
    Parent = '' ()
    Reference = '' (WindowsFormsApplication2.Reference)
Before referencing SomethingElses.Local:
    Name = 'AlphaTwo'
    Parent = '' ()
    Reference = 'Reference' ()
After referencing SomethingElses.Local:
    Name = 'AlphaOne'
    Parent = 'Alpha' (WindowsFormsApplication2.Parent)
    Reference = '' (WindowsFormsApplication2.Reference)
After referencing SomethingElses.Local:
    Name = 'AlphaTwo'
    Parent = 'Alpha' (WindowsFormsApplication2.Parent)
    Reference = 'Reference' ()
Before SaveChanges:
    Name = 'AlphaOne'
    Parent = 'Alpha' (WindowsFormsApplication2.Parent)
    Reference = '' (WindowsFormsApplication2.Reference)
Before SaveChanges:
    Name = 'AlphaTwo'
    Parent = 'Alpha' (WindowsFormsApplication2.Parent)
    Reference = 'Reference' ()
After SaveChanges:
    Name = 'AlphaOne'
    Parent = 'Alpha' (WindowsFormsApplication2.Parent)
    Reference = 'Reference' (WindowsFormsApplication2.Reference)
After SaveChanges:
    Name = 'AlphaTwo'
    Parent = 'Alpha' (WindowsFormsApplication2.Parent)
    Reference = 'Reference' (WindowsFormsApplication2.Reference)

Answer 2

从v2.0.8开始，您还可以执行以下操作：

$this->addColumn('news', 'priority', $this->integer()->after('name'));

请参见https://github.com/yiisoft/yii2/blob/2.0.8/framework/db/ColumnSchemaBuilder.php#L209

Yii2迁移 - 在另一个之后添加列

2 个答案: