[C#] Enable index in SQLite (Code First)

We should specify which column would be indexed in the function 'OnModelCreating'

        protected override void OnModelCreating( ModelBuilder modelBuilder )
        {
            modelBuilder.Entity().HasIndex(b => new { b.Time });
            modelBuilder.Entity().HasIndex(b => new { b.CarAppraisalLicense });
            modelBuilder.Entity().HasIndex(b => new { b._CreateTime});
            modelBuilder.Entity().HasIndex(b => new { b._ModifiedTime });

            modelBuilder.Entity().HasIndex(b => new { b.carPlateModify});
            modelBuilder.Entity().HasIndex(b => new { b.licenseRfid});
            modelBuilder.Entity().HasIndex(b => new { b.carRfid});
            modelBuilder.Entity().HasIndex(b => new { b.updateTime });

            modelBuilder.Entity().HasIndex(b => new { b.licenseRfid });
            modelBuilder.Entity().HasIndex(b => new { b.licenseNo});
            modelBuilder.Entity().HasIndex(b => new { b.updateTime});
        }

Then do EF migration, downgrade/upgrade codes will be generated autometically.

    public partial class CreateIndex : Migration
    {
        protected override void Up(MigrationBuilder migrationBuilder)
        {
            migrationBuilder.CreateIndex(
                name: "IX_VerifyLogs_CarAppraisalLicense",
                table: "VerifyLogs",
                column: "CarAppraisalLicense");

            migrationBuilder.CreateIndex(
                name: "IX_VerifyLogs_Time",
                table: "VerifyLogs",
                column: "Time");

            migrationBuilder.CreateIndex(
                name: "IX_VerifyLogs__CreateTime",
                table: "VerifyLogs",
                column: "_CreateTime");

            migrationBuilder.CreateIndex(
                name: "IX_VerifyLogs__ModifiedTime",
                table: "VerifyLogs",
                column: "_ModifiedTime");

            migrationBuilder.CreateIndex(
                name: "IX_DriverLicenses_licenseNo",
                table: "DriverLicenses",
                column: "licenseNo");

            migrationBuilder.CreateIndex(
                name: "IX_DriverLicenses_licenseRfid",
                table: "DriverLicenses",
                column: "licenseRfid");

            migrationBuilder.CreateIndex(
                name: "IX_DriverLicenses_updateTime",
                table: "DriverLicenses",
                column: "updateTime");

            migrationBuilder.CreateIndex(
                name: "IX_CarLicenses_carPlateModify",
                table: "CarLicenses",
                column: "carPlateModify");

            migrationBuilder.CreateIndex(
                name: "IX_CarLicenses_carRfid",
                table: "CarLicenses",
                column: "carRfid");

            migrationBuilder.CreateIndex(
                name: "IX_CarLicenses_licenseRfid",
                table: "CarLicenses",
                column: "licenseRfid");

            migrationBuilder.CreateIndex(
                name: "IX_CarLicenses_updateTime",
                table: "CarLicenses",
                column: "updateTime");
        }

        protected override void Down(MigrationBuilder migrationBuilder)
        {
            migrationBuilder.DropIndex(
                name: "IX_VerifyLogs_CarAppraisalLicense",
                table: "VerifyLogs");

            migrationBuilder.DropIndex(
                name: "IX_VerifyLogs_Time",
                table: "VerifyLogs");

            migrationBuilder.DropIndex(
                name: "IX_VerifyLogs__CreateTime",
                table: "VerifyLogs");

            migrationBuilder.DropIndex(
                name: "IX_VerifyLogs__ModifiedTime",
                table: "VerifyLogs");

            migrationBuilder.DropIndex(
                name: "IX_DriverLicenses_licenseNo",
                table: "DriverLicenses");

            migrationBuilder.DropIndex(
                name: "IX_DriverLicenses_licenseRfid",
                table: "DriverLicenses");

            migrationBuilder.DropIndex(
                name: "IX_DriverLicenses_updateTime",
                table: "DriverLicenses");

            migrationBuilder.DropIndex(
                name: "IX_CarLicenses_carPlateModify",
                table: "CarLicenses");

            migrationBuilder.DropIndex(
                name: "IX_CarLicenses_carRfid",
                table: "CarLicenses");

            migrationBuilder.DropIndex(
                name: "IX_CarLicenses_licenseRfid",
                table: "CarLicenses");

            migrationBuilder.DropIndex(
                name: "IX_CarLicenses_updateTime",
                table: "CarLicenses");
        }
    }

After creating the index, we can reduce 1/10 DB query time on average.