一 migration的使用
命令一共有5种，每个有两种写法：
参考 https://www.cnblogs.com/nsky/p/10323415.html
dotnet ef database drop 删除库

　　dotnet ef migrations add initialCreate ||　　Add-Migrantion (执行此命令项目生成一个目录（Migrations））

　　dotnet ef database update 　　　　||　　Update-Database (把当前的Migrations更新到数据库中)

　　dotnet ef migrations remove　　　　　 ||　　Remove-Migration (删除一个最新的Migrations，降级，根据数据库表结构删除migrations文件夹下面多余的文件)

　　dotnet ef database update　LastGoodMigration　　　　　||　　 　　Update-Database LastGoodMigration（指定一个Migrations更新 LastGoodMigration 指定的migration名称）

　　dotnet ef migrations script　　　　　　 || 　　Script-Migration 　　（将更新内容生成sql脚本语句）

dotnet ef migratoins remove 是移除最新的一个migration，remove一次就移除一次

 dotnet ef migrations script -o d:\script\user.sql  

二 migrationBuilder命令
'''script
1
protected override void Up(MigrationBuilder migrationBuilder)
{
migrationBuilder.CreateTable(
name: "Club",
columns: table => new
{
Id = table.Column(nullable: false)
.Annotation("SqlServer:ValueGenerationStrategy", SqlServerValueGenerationStrategy.IdentityColumn),
Name = table.Column(nullable: true)
},
constraints: table =>
{
table.PrimaryKey("PK_Club", x => x.Id);
});
migrationBuilder.CreateTable(
name: "Team",
columns: table => new
{
Id = table.Column(nullable: false)
.Annotation("SqlServer:ValueGenerationStrategy", SqlServerValueGenerationStrategy.IdentityColumn),
ClubId = table.Column(nullable: false),
Name = table.Column(nullable: true)
},
constraints: table =>
{
table.PrimaryKey("PK_Team", x => x.Id);
table.ForeignKey(
name: "FK_Team_Club_ClubId",
column: x => x.ClubId,
principalTable: "Club",
principalColumn: "Id",
onDelete: ReferentialAction.Cascade);
});
}

2

protected override void Up(MigrationBuilder migrationBuilder)
{
migrationBuilder.EnsureSchema("mab");
migrationBuilder.CreateTable(
name: "MicroAggression",
schema: "mab",
columns: table => new
{
Aggression = table.Column(nullable: false),
Aggressiveness = table.Column(nullable: false),
Created = table.Column(nullable: false),
_Alternatives = table.Column(nullable: true)
},
constraints: table =>
{
table.PrimaryKey("PK_MicroAggression", x => x.Aggression);
});
migrationBuilder.CreateTable(
name: "Offense",
schema: "mab",
columns: table => new
{
Id = table.Column(nullable: false),
Offenses = table.Column(nullable: false),
User = table.Column(nullable: true)
},
constraints: table =>
{
table.PrimaryKey("PK_Offense", x => x.Id);
});
migrationBuilder.CreateTable(
name: "Correction",
schema: "mab",
columns: table => new
{
Id = table.Column(nullable: false),
Created = table.Column(nullable: false),
MicroAggressionId = table.Column(nullable: true),
OffenseId = table.Column(nullable: false),
Tweet = table.Column(nullable: true)
},
constraints: table =>
{
table.PrimaryKey("PK_Correction", x => x.Id);
table.ForeignKey(
name: "FK_Correction_MicroAggression_MicroAggressionId",
column: x => x.MicroAggressionId,
principalSchema: "mab",
principalTable: "MicroAggression",
principalColumn: "Aggression",
onDelete: ReferentialAction.Restrict);
table.ForeignKey(
name: "FK_Correction_Offense_OffenseId",
column: x => x.OffenseId,
principalSchema: "mab",
principalTable: "Offense",
principalColumn: "Id",
onDelete: ReferentialAction.Restrict);
});
}

3
public override void Up(MigrationBuilder migration)
{
migration.CreateTable(
name: "Blog",
columns: table => new
{
BlogId = table.Column(type: "int", nullable: false)
.Annotation("SqlServer:ValueGenerationStrategy", "IdentityColumn"),
Url = table.Column(type: "nvarchar(max)", nullable: false)
},
constraints: table =>
{
table.PrimaryKey("PK_Blog", x => x.BlogId);
});
migration.CreateTable(
name: "Post",
columns: table => new
{
PostId = table.Column(type: "int", nullable: false)
.Annotation("SqlServer:ValueGenerationStrategy", "IdentityColumn"),
BlogId = table.Column(type: "int", nullable: false),
Content = table.Column(type: "nvarchar(max)", nullable: true),
Title = table.Column(type: "nvarchar(max)", nullable: true)
},
constraints: table =>
{
table.PrimaryKey("PK_Post", x => x.PostId);
table.ForeignKey(
name: "FK_Post_Blog_BlogId",
columns: x => x.BlogId,
referencedTable: "Blog",
referencedColumn: "BlogId");
});
}

4
protected override void Up(MigrationBuilder migrationBuilder)
{
migrationBuilder.CreateTable(
name: "Manufacturer",
columns: table => new
{
Id = table.Column(isNullable: false)
.Annotation("SqlServer:ValueGenerationStrategy", SqlServerIdentityStrategy.IdentityColumn),
Name = table.Column(isNullable: true)
},
constraints: table =>
{
table.PrimaryKey("PK_Manufacturer", x => x.Id);
});
migrationBuilder.CreateTable(
name: "Model",
columns: table => new
{
Id = table.Column(isNullable: false)
.Annotation("SqlServer:ValueGenerationStrategy", SqlServerIdentityStrategy.IdentityColumn),
Name = table.Column(isNullable: true)
},
constraints: table =>
{
table.PrimaryKey("PK_Model", x => x.Id);
});
}
5
protected override void Up(MigrationBuilder migrationBuilder)
{
migrationBuilder.CreateTable(
name: "Contacts",
columns: table => new
{
Id = table.Column(nullable: false)
.Annotation("SqlServer:ValueGenerationStrategy", SqlServerValueGenerationStrategy.IdentityColumn),
FirstName = table.Column(nullable: true),
LastName = table.Column(nullable: true)
},
constraints: table =>
{
table.PrimaryKey("PK_Contacts", x => x.Id);
});

        migrationBuilder.CreateTable(
            name: "Customers",
            columns: table => new
            {
                Id = table.Column<int>(nullable: false)
                    .Annotation("SqlServer:ValueGenerationStrategy", SqlServerValueGenerationStrategy.IdentityColumn),
                CustomerName = table.Column<string>(nullable: true)
            },
            constraints: table =>
            {
                table.PrimaryKey("PK_Customers", x => x.Id);
            });
    }

6
protected override void Up(MigrationBuilder migrationBuilder)
{
migrationBuilder.CreateTable(
name: "Issue",
columns: table => new
{
Id = table.Column(nullable: false)
.Annotation("SqlServer:ValueGenerationStrategy", SqlServerValueGenerationStrategy.IdentityColumn),
Created = table.Column(nullable: false),
Name = table.Column(nullable: true)
},
constraints: table =>
{
table.PrimaryKey("PK_Issue", x => x.Id);
});
migrationBuilder.CreateTable(
name: "Person",
columns: table => new
{
Id = table.Column(nullable: false)
.Annotation("SqlServer:ValueGenerationStrategy", SqlServerValueGenerationStrategy.IdentityColumn),
IssueId = table.Column(nullable: true),
Name = table.Column(nullable: true)
},
constraints: table =>
{
table.PrimaryKey("PK_Person", x => x.Id);
table.ForeignKey(
name: "FK_Person_Issue_IssueId",
column: x => x.IssueId,
principalTable: "Issue",
principalColumn: "Id",
onDelete: ReferentialAction.Restrict);
});
}

7
protected override void Up(MigrationBuilder migrationBuilder)
{
migrationBuilder.CreateTable(
name: "Teacher",
columns: table => new
{
ID = table.Column(nullable: false)
.Annotation("SqlServer:ValueGenerationStrategy", SqlServerValueGenerationStrategy.IdentityColumn),
Name = table.Column(nullable: true)
},
constraints: table =>
{
table.PrimaryKey("PK_Teacher", x => x.ID);
});
migrationBuilder.CreateTable(
name: "Student",
columns: table => new
{
ID = table.Column(nullable: false)
.Annotation("SqlServer:ValueGenerationStrategy", SqlServerValueGenerationStrategy.IdentityColumn),
Name = table.Column(nullable: true),
TeacherID = table.Column(nullable: false)
},
constraints: table =>
{
table.PrimaryKey("PK_Student", x => x.ID);
table.ForeignKey(
name: "FK_Student_Teacher_TeacherID",
column: x => x.TeacherID,
principalTable: "Teacher",
principalColumn: "ID",
onDelete: ReferentialAction.Cascade);
});
}

8
protected override void Up(MigrationBuilder migrationBuilder)
{
migrationBuilder.CreateTable(
name: "Game",
columns: table => new
{
Id = table.Column(nullable: false)
.Annotation("SqlServer:ValueGenerationStrategy", SqlServerValueGenerationStrategy.IdentityColumn),
Opponent = table.Column(nullable: true),
Order = table.Column(nullable: false)
},
constraints: table =>
{
table.PrimaryKey("PK_Game", x => x.Id);
});
migrationBuilder.CreateTable(
name: "StatLine",
columns: table => new
{
Id = table.Column(nullable: false)
.Annotation("SqlServer:ValueGenerationStrategy", SqlServerValueGenerationStrategy.IdentityColumn),
Assists = table.Column(nullable: false),
FGPercentage = table.Column(nullable: false),
FieldGoals = table.Column(nullable: false),
FieldGoalsAttempted = table.Column(nullable: false),
GameNumber = table.Column(nullable: false),
Player = table.Column(nullable: true),
Points = table.Column(nullable: false),
Rebounds = table.Column(nullable: false)
},
constraints: table =>
{
table.PrimaryKey("PK_StatLine", x => x.Id);
});
}

9
protected override void Up(MigrationBuilder migrationBuilder)
{
migrationBuilder.CreateTable(
name: "CalendarEvent",
columns: table => new
{
Id = table.Column(isNullable: false),
Body = table.Column(isNullable: true),
End = table.Column(isNullable: false),
IsAllDay = table.Column(isNullable: true),
Location = table.Column(isNullable: true),
Start = table.Column(isNullable: false),
Subject = table.Column(isNullable: true)
},
constraints: table =>
{
table.PrimaryKey("PK_CalendarEvent", x => x.Id);
});
migrationBuilder.CreateTable(
name: "Emails",
columns: table => new
{
Id = table.Column(isNullable: false),
Body = table.Column(isNullable: true),
DateTimeSent = table.Column(isNullable: false),
From = table.Column(isNullable: true),
Subject = table.Column(isNullable: true)
},
constraints: table =>
{
table.PrimaryKey("PK_Emails", x => x.Id);
});
}

10
protected override void Up(MigrationBuilder migrationBuilder)
{
migrationBuilder.DropTable(name: "CorrectedTweets", schema: "mab");
migrationBuilder.CreateTable(
name: "CorrectedTweet",
schema: "mab",
columns: table => new
{
Id = table.Column(nullable: false),
CorrectedOn = table.Column(nullable: false),
ScreenName = table.Column(nullable: true),
StatusId = table.Column(nullable: false)
},
constraints: table =>
{
table.PrimaryKey("PK_CorrectedTweet", x => x.Id);
});
migrationBuilder.CreateTable(
name: "OutgoingTweet",
schema: "mab",
columns: table => new
{
Id = table.Column(nullable: false),
InReplyToScreenName = table.Column(nullable: true),
InReplyToStatusId = table.Column(nullable: false),
Text = table.Column(nullable: true)
},
constraints: table =>
{
table.PrimaryKey("PK_OutgoingTweet", x => x.Id);
});
}

11
protected override void Up(MigrationBuilder migrationBuilder)
{
migrationBuilder.CreateTable(
name: "AnswerData",
columns: table => new
{
Id = table.Column(nullable: false),
AnsweredBy = table.Column(nullable: true),
Content = table.Column(nullable: true),
QuestionId = table.Column(nullable: false),
Votes = table.Column(nullable: false)
},
constraints: table =>
{
table.PrimaryKey("PK_AnswerData", x => x.Id);
});
migrationBuilder.CreateTable(
name: "QuestionData",
columns: table => new
{
Id = table.Column(nullable: false),
AskedByUserName = table.Column(nullable: true),
Content = table.Column(nullable: true)
},
constraints: table =>
{
table.PrimaryKey("PK_QuestionData", x => x.Id);
});
}

12

protected override void Up(MigrationBuilder migrationBuilder)
{
migrationBuilder.CreateTable(
name: "Role",
columns: table => new
{
RoleID = table.Column(nullable: false),
Description = table.Column(nullable: false)
},
constraints: table =>
{
table.PrimaryKey("PK_Role", x => x.RoleID);
});
migrationBuilder.CreateTable(
name: "User",
columns: table => new
{
UserID = table.Column(nullable: false)
.Annotation("SqlServer:ValueGenerationStrategy", SqlServerValueGenerationStrategy.IdentityColumn),
CustomProperty = table.Column(nullable: true),
Email = table.Column(nullable: true),
Password = table.Column(nullable: false),
RoleID = table.Column(nullable: false),
Username = table.Column(nullable: false)
},
constraints: table =>
{
table.PrimaryKey("PK_User", x => x.UserID);
table.ForeignKey(
name: "FK_User_Role_RoleID",
column: x => x.RoleID,
principalTable: "Role",
principalColumn: "RoleID");
});
}

13

protected override void Up(MigrationBuilder migrationBuilder)
{
migrationBuilder.CreateTable(
name: "Migrations",
columns: table => new
{
Context = table.Column(nullable: false),
Version = table.Column(nullable: false),
Metadata = table.Column(type: "ntext", nullable: false),
Migration = table.Column(type: "ntext", nullable: false)
},
constraints: table =>
{
table.PrimaryKey("PK_Migrations", x => new { x.Context, x.Version });
});

        migrationBuilder.CreateTable(
            name: "Snapshots",
            columns: table => new
            {
                Context = table.Column<string>(nullable: false),
                Version = table.Column<string>(nullable: false),
                Snapshot = table.Column<string>(type: "ntext", nullable: false)
            },
            constraints: table =>
            {
                table.PrimaryKey("PK_Snapshots", x => x.Context);
            });
    }

14

protected override void Up(MigrationBuilder migrationBuilder)
{
migrationBuilder.CreateTable(
name: "Level",
columns: table => new
{
Id = table.Column(nullable: false)
.Annotation("SqlServer:ValueGenerationStrategy", SqlServerValueGenerationStrategy.IdentityColumn),
Created = table.Column(nullable: false),
Name = table.Column(nullable: true),
UserName = table.Column(nullable: true)
},
constraints: table =>
{
table.PrimaryKey("PK_Level", x => x.Id);
});
migrationBuilder.CreateTable(
name: "Quest",
columns: table => new
{
Id = table.Column(nullable: false)
.Annotation("SqlServer:ValueGenerationStrategy", SqlServerValueGenerationStrategy.IdentityColumn),
DueBy = table.Column(nullable: false),
Name = table.Column(nullable: true),
Reward = table.Column(nullable: true),
Status = table.Column(nullable: true)
},
constraints: table =>
{
table.PrimaryKey("PK_Quest", x => x.Id);
});
}

15
protected override void Up(MigrationBuilder migrationBuilder)
{
migrationBuilder.CreateTable(
name: "State",
columns: table => new
{
Id = table.Column(nullable: false)
.Annotation("SqlServer:ValueGenerationStrategy", SqlServerValueGenerationStrategy.IdentityColumn),
Name = table.Column(nullable: false)
},
constraints: table =>
{
table.PrimaryKey("PK_State", x => x.Id);
});
migrationBuilder.CreateTable(
name: "Message",
columns: table => new
{
Id = table.Column(nullable: false)
.Annotation("SqlServer:ValueGenerationStrategy", SqlServerValueGenerationStrategy.IdentityColumn),
StateId = table.Column(nullable: false),
Text = table.Column(nullable: false)
},
constraints: table =>
{
table.PrimaryKey("PK_Message", x => x.Id);
table.ForeignKey(
name: "FK_Message_State_StateId",
column: x => x.StateId,
principalTable: "State",
principalColumn: "Id");
});
}

添加列 删除列
//向上迁移，会增加一列
protected override void Up(MigrationBuilder migrationBuilder)
{
migrationBuilder.AddColumn(
name: "Height",
table: "T_Persons",
nullable: false,
maxLength: 50,
defaultValue: 0.0);
}

    protected override void Down(MigrationBuilder migrationBuilder)
    {
        //向下迁移就会删除T_Persons表中的Height列
        migrationBuilder.DropColumn(
            name: "Height",
            table: "T_Persons");
    }

删除外键
migrationBuilder.DropForeignKey(
name: "FK_CourseAssignment_Instructor_InstructorID",
table: "CourseAssignment");

删除索引
migrationBuilder.DropIndex(name: "IX_Enrollment_StudentID", table: "Enrollment");

        migrationBuilder.RenameTable(name: "Instructor", newName: "Person");  重命名表
        migrationBuilder.AddColumn<DateTime>(name: "EnrollmentDate", table: "Person", nullable: true); 添加列
        migrationBuilder.AddColumn<string>(name: "Discriminator", table: "Person", nullable: false, maxLength: 128, defaultValue: "Instructor")；修改列
        migrationBuilder.AlterColumn<DateTime>(name: "HireDate", table: "Person", nullable: true);
        migrationBuilder.AddColumn<int>(name: "OldId", table: "Person", nullable: true);

migrationBuilder.DropColumn(name: "OldID", table: "Person");

migrationBuilder.Sql(""）; 执行sql
添加外键
migrationBuilder.AddForeignKey(
name: "FK_Enrollment_Person_StudentID",
table: "Enrollment",
column: "StudentID",
principalTable: "Person",
principalColumn: "ID",
onDelete: ReferentialAction.Cascade);
添加索引
migrationBuilder.CreateIndex(
name: "IX_Enrollment_StudentID",
table: "Enrollment",
column: "StudentID");
}
主键
table.PrimaryKey("PK_IdentityUserClaim", x => x.Id);
table.PrimaryKey("PK_IdentityUserLogin", x => new { x.LoginProvider, x.ProviderKey });

   默认值
    migrationBuilder.AddColumn<DateTimeOffset>(
            name: "EndDateTime",
            table: "Activity",
            nullable: false,
            defaultValue: new DateTimeOffset(new DateTime(1, 1, 1, 0, 0, 0, 0, DateTimeKind.Unspecified), new TimeSpan(0, 0, 0, 0, 0)));
        migrationBuilder.AddColumn<DateTimeOffset>(
            name: "StartDateTime",
            table: "Activity",
            nullable: false,
            defaultValue: new DateTimeOffset(new DateTime(1, 1, 1, 0, 0, 0, 0, DateTimeKind.Unspecified), new TimeSpan(0, 0, 0, 0, 0)));

添加列参数
public virtual Microsoft.EntityFrameworkCore.Migrations.Operations.Builders.OperationBuilder<Microsoft.EntityFrameworkCore.Migrations.Operations.AddColumnOperation> AddColumn (string name, string table, string? type = default, bool? unicode = default, int? maxLength = default, bool rowVersion = false, string? schema = default, bool nullable = false, object? defaultValue = default, string? defaultValueSql = default, string? computedColumnSql = default, bool? fixedLength = default, string? comment = default, string? collation = default, int? precision = default, int? scale = default, bool? stored = default);

添加表参数
public virtual Microsoft.EntityFrameworkCore.Migrations.Operations.Builders.CreateTableBuilder CreateTable (string name, Func<Microsoft.EntityFrameworkCore.Migrations.Operations.Builders.ColumnsBuilder,TColumns> columns, string? schema = default, Action<Microsoft.EntityFrameworkCore.Migrations.Operations.Builders.CreateTableBuilder>? constraints = default, string? comment = default);
''''