Pomelo.entityframeworkcore.mysql: How to get all table names with Pomelo.EntityFrameworkCore.MySql?

Created on 24 Dec 2020  ·  4Comments  ·  Source: PomeloFoundation/Pomelo.EntityFrameworkCore.MySql

I want to check some table is existed, so how to get all table names?

use CreateCommand() to do a custom query?

closed-question type-question

Most helpful comment

Uh oh, maybe I can't, I've got question limit on Stack Overflow. - Too much personal question...

@Flithor In that case, here is the promised sample code:

```c#
using System;
using System.Collections.Generic;
using System.Diagnostics;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Logging;
using Pomelo.EntityFrameworkCore.MySql.Infrastructure;

namespace IssueConsoleTemplate
{
public class IceCream
{
public int IceCreamId { get; set; }
public string Name { get; set; }
}

public class Context : DbContext
{
    public DbSet<IceCream> IceCreams { get; set; }

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {
        optionsBuilder
            .UseMySql(
                "server=127.0.0.1;port=3306;user=root;password=;database=Issue1279",
                b => b.ServerVersion("8.0.21-mysql")
                      .CharSetBehavior(CharSetBehavior.NeverAppend))
            .UseLoggerFactory(
                LoggerFactory.Create(
                    b => b.AddConsole()
                        .AddFilter(level => level >= LogLevel.Information)))
            .EnableSensitiveDataLogging()
            .EnableDetailedErrors();
    }
}

internal static class Program
{
    private static void Main()
    {
        using var context = new Context();

        context.Database.EnsureDeleted();
        context.Database.EnsureCreated();

        var tableNames = GetTableNames(context);

        Trace.Assert(tableNames.Contains("IceCreams"));
    }

    private static List<string> GetTableNames(DbContext context)
    {
        // EF Core will close the connection automatically for us, when we ensure, that it is EF Core itself that is
        // responsible for opening the database connection. We can ensure that by calling `OpenConnection()` first.
        context.Database.OpenConnection();

        var connection = context.Database.GetDbConnection();

        using var command = connection.CreateCommand();
        command.CommandText = @"select `TABLE_NAME`

from INFORMATION_SCHEMA.TABLES
where TABLE_SCHEMA = database();";

        var tableNames = new List<string>();

        using var reader = command.ExecuteReader();
        while (reader.Read())
        {
            tableNames.Add((string) reader["TABLE_NAME"]);
        }

        return tableNames;
    }
}

}
```

All 4 comments

Yes a custom query like SHOW TABLES; would work. Please ask this question on Stack Overflow for further help as issues aren't meant for this purpose.

@Flithor I'll answer you with some sample code on Stack Overflow, once you have posted your question over there. Please use the pomelo-entityframeworkcore-mysql tag, so I will be notified (its an MySQL and EF Core related question, so close enough).

Uh oh, maybe I can't, I've got question limit on Stack Overflow. - Too much personal question...
(I'll edited title for help others)

Uh oh, maybe I can't, I've got question limit on Stack Overflow. - Too much personal question...

@Flithor In that case, here is the promised sample code:

```c#
using System;
using System.Collections.Generic;
using System.Diagnostics;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Logging;
using Pomelo.EntityFrameworkCore.MySql.Infrastructure;

namespace IssueConsoleTemplate
{
public class IceCream
{
public int IceCreamId { get; set; }
public string Name { get; set; }
}

public class Context : DbContext
{
    public DbSet<IceCream> IceCreams { get; set; }

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {
        optionsBuilder
            .UseMySql(
                "server=127.0.0.1;port=3306;user=root;password=;database=Issue1279",
                b => b.ServerVersion("8.0.21-mysql")
                      .CharSetBehavior(CharSetBehavior.NeverAppend))
            .UseLoggerFactory(
                LoggerFactory.Create(
                    b => b.AddConsole()
                        .AddFilter(level => level >= LogLevel.Information)))
            .EnableSensitiveDataLogging()
            .EnableDetailedErrors();
    }
}

internal static class Program
{
    private static void Main()
    {
        using var context = new Context();

        context.Database.EnsureDeleted();
        context.Database.EnsureCreated();

        var tableNames = GetTableNames(context);

        Trace.Assert(tableNames.Contains("IceCreams"));
    }

    private static List<string> GetTableNames(DbContext context)
    {
        // EF Core will close the connection automatically for us, when we ensure, that it is EF Core itself that is
        // responsible for opening the database connection. We can ensure that by calling `OpenConnection()` first.
        context.Database.OpenConnection();

        var connection = context.Database.GetDbConnection();

        using var command = connection.CreateCommand();
        command.CommandText = @"select `TABLE_NAME`

from INFORMATION_SCHEMA.TABLES
where TABLE_SCHEMA = database();";

        var tableNames = new List<string>();

        using var reader = command.ExecuteReader();
        while (reader.Read())
        {
            tableNames.Add((string) reader["TABLE_NAME"]);
        }

        return tableNames;
    }
}

}
```

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