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MigrationsBuilder Class

Represents a tool for building a Migration. This class is used by the EF Core tooling to generate the code for migrations.

namespace Microsoft.EntityFrameworkCore.Migrations
public class MigrationsBuilder

Description

The MigrationsBuilder class provides a fluent API for defining the operations that should be performed by a migration. These operations typically involve schema changes to your database, such as creating tables, adding columns, or modifying constraints.

Methods

AddColumn<TProperty>(string table, string name, Action<ColumnOperation> property = null)

public virtual ColumnOperation AddColumn<TProperty>(string table, string name, Action<ColumnOperation> property = null)

Adds a new column to an existing table.

Parameters

string table
The name of the table to add the column to.
string name
The name of the new column.
Action<ColumnOperation> property
An optional action to configure the properties of the column.

Returns

ColumnOperation: An object representing the operation to add the column.

CreateTable(string name, Action<TableOperation> columns)

public virtual TableOperation CreateTable(string name, Action<TableOperation> columns)

Creates a new table in the database.

Parameters

string name
The name of the table to create.
Action<TableOperation> columns
An action to define the columns and constraints of the table.

Returns

TableOperation: An object representing the operation to create the table.

DropTable(string name)

public virtual TableOperation DropTable(string name)

Drops an existing table from the database.

Parameters

string name
The name of the table to drop.

Returns

TableOperation: An object representing the operation to drop the table.

Example

Using MigrationsBuilder to create a migration


using Microsoft.EntityFrameworkCore.Migrations;

namespace MyProject.Migrations
{
    public partial class AddUsersTable : Migration
    {
        protected override void Up(MigrationBuilder migrationBuilder)
        {
            migrationBuilder.CreateTable(
                name: "Users",
                columns: table => new
                {
                    Id = table.Column<int>(nullable: false)
                        .Annotation("SqlServer:ValueGenerationStrategy", SqlServerValueGenerationStrategy.IdentityColumn),
                    Username = table.Column<string>(maxLength: 50),
                    Email = table.Column<string>(nullable: false)
                },
                constraints: table =>
                {
                    table.PrimaryKey("PK_Users", x => x.Id);
                });

            migrationBuilder.AddColumn<DateTime>(
                name: "CreatedAt",
                table: "Users",
                nullable: false,
                defaultValue: new DateTime(1, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc));
        }

        protected override void Down(MigrationBuilder migrationBuilder)
        {
            migrationBuilder.DropColumn(
                name: "CreatedAt",
                table: "Users");

            migrationBuilder.DropTable(
                name: "Users");
        }
    }
}

See Also