asp.net 显示指定密钥的核心 2 太长； 最大密钥长度为 3072 字节

Question

I am working on .net core 2. I am using mysql as database. When i am writing the following code dbContext.Database.EnsureCreated(); it is generating me an error

MySql.Data.MySqlClient.MySqlException: 'Specified key was too long; max key length is 3072 bytes'

public void Configure(IApplicationBuilder app, IHostingEnvironment env, ApplicationDbContext dbContext)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }

            // ===== Create tables ======
            dbContext.Database.EnsureCreated();

            app.UseMvc();
        }

I am able to generate roleclaims, roles, userclaims, users successfully. I am using applicationDbcontext which is extending IdentityDbContext.

How can this error be resolved. need help thanks in advance.

Answer 1

I also face this issue what i do is

1. Open command prompt and go to project location then run following command

   dotnet ef migrations script -o initial.sql

2. It will generate sql, open the file and remove all VARCHAR(767) with VARCHAR(100)

run the sql in sqlyog/workbench you first migration will be created & now you can continue work.

and for rest of migrations make sure do not make primary key varchar for greater length or use int

Thanks

Answer 2

Not a fix, but a simple workaround when Irfan's answer does not apply.

After receiving this error, I addressed the potential issue of keys from combined fields exceeding the limit by setting their max sizes in the migration Up method - this did not help.

I generated a script in Package Manager Console with script-migration -o initial.sql -context MyDbContextName and saw that there were no exceptional varchars in the stored migrations.

I gave up on a code solution and did this: -

1. In MySQL Workbench, create the empty schema (database) by right-clicking in an empty part of the Schemas tab and choosing Create Schema.
2. In Package Manager Console, run update-database -context ApplicationDbContext .