ChatBot/ChatBot/Migrations/20251016214154_InitialCreate.cs

using System;
using Microsoft.EntityFrameworkCore.Migrations;
using Npgsql.EntityFrameworkCore.PostgreSQL.Metadata;

#nullable disable

namespace ChatBot.Migrations
{
    /// <inheritdoc />
    public partial class InitialCreate : Migration
    {
        private const string ChatSessionsTableName = "chat_sessions";
        private const string ChatMessagesTableName = "chat_messages";
        private const string ChatSessionsIdColumn = "id";
        private const string ChatMessagesSessionIdColumn = "session_id";
        private const string IntegerType = "integer";

        /// <inheritdoc />
        protected override void Up(MigrationBuilder migrationBuilder)
        {
            migrationBuilder.CreateTable(
                name: ChatSessionsTableName,
                columns: table => new
                {
                    id = table
                        .Column<int>(type: IntegerType, nullable: false)
                        .Annotation(
                            "Npgsql:ValueGenerationStrategy",
                            NpgsqlValueGenerationStrategy.IdentityByDefaultColumn
                        ),
                    session_id = table.Column<string>(
                        type: "character varying(50)",
                        maxLength: 50,
                        nullable: false
                    ),
                    chat_id = table.Column<long>(type: "bigint", nullable: false),
                    chat_type = table.Column<string>(
                        type: "character varying(20)",
                        maxLength: 20,
                        nullable: false
                    ),
                    chat_title = table.Column<string>(
                        type: "character varying(200)",
                        maxLength: 200,
                        nullable: false
                    ),
                    model = table.Column<string>(
                        type: "character varying(100)",
                        maxLength: 100,
                        nullable: false
                    ),
                    created_at = table.Column<DateTime>(
                        type: "timestamp with time zone",
                        nullable: false
                    ),
                    last_updated_at = table.Column<DateTime>(
                        type: "timestamp with time zone",
                        nullable: false
                    ),
                    max_history_length = table.Column<int>(type: IntegerType, nullable: false),
                },
                constraints: table =>
                {
                    table.PrimaryKey("PK_chat_sessions", x => x.id);
                }
            );

            migrationBuilder.CreateTable(
                name: ChatMessagesTableName,
                columns: table => new
                {
                    id = table
                        .Column<int>(type: IntegerType, nullable: false)
                        .Annotation(
                            "Npgsql:ValueGenerationStrategy",
                            NpgsqlValueGenerationStrategy.IdentityByDefaultColumn
                        ),
                    session_id = table.Column<int>(type: IntegerType, nullable: false),
                    content = table.Column<string>(
                        type: "character varying(10000)",
                        maxLength: 10000,
                        nullable: false
                    ),
                    role = table.Column<string>(
                        type: "character varying(20)",
                        maxLength: 20,
                        nullable: false
                    ),
                    created_at = table.Column<DateTime>(
                        type: "timestamp with time zone",
                        nullable: false
                    ),
                    message_order = table.Column<int>(type: IntegerType, nullable: false),
                },
                constraints: table =>
                {
                    table.PrimaryKey("PK_chat_messages", x => x.id);
                    table.ForeignKey(
                        name: "FK_chat_messages_chat_sessions_session_id",
                        column: x => x.session_id,
                        principalTable: ChatSessionsTableName,
                        principalColumn: ChatSessionsIdColumn,
                        onDelete: ReferentialAction.Cascade
                    );
                }
            );

            migrationBuilder.CreateIndex(
                name: "IX_chat_messages_created_at",
                table: ChatMessagesTableName,
                column: "created_at"
            );

            migrationBuilder.CreateIndex(
                name: "IX_chat_messages_session_id",
                table: ChatMessagesTableName,
                column: ChatMessagesSessionIdColumn
            );

            migrationBuilder.CreateIndex(
                name: "IX_chat_messages_session_id_message_order",
                table: ChatMessagesTableName,
                columns: new[] { ChatMessagesSessionIdColumn, "message_order" }
            );

            migrationBuilder.CreateIndex(
                name: "IX_chat_sessions_chat_id",
                table: ChatSessionsTableName,
                column: "chat_id"
            );

            migrationBuilder.CreateIndex(
                name: "IX_chat_sessions_session_id",
                table: ChatSessionsTableName,
                column: "session_id",
                unique: true
            );
        }

        /// <inheritdoc />
        protected override void Down(MigrationBuilder migrationBuilder)
        {
            migrationBuilder.DropTable(name: ChatMessagesTableName);

            migrationBuilder.DropTable(name: ChatSessionsTableName);
        }
    }
}