Orm.Utilities.cs

using System.Data;
using Dapper;
using SwiftSQL.Dialects;

namespace SwiftSQL;

public static partial class Orm
{
    public static async Task<bool> TableExistsAsync(
        IDbConnection connection,
        ISqlDialect dialect,
        string tableName,
        IDbTransaction? transaction = null,
        CancellationToken cancellationToken = default)
    {
        var sql = dialect.Name switch
        {
            "SQLite" => "SELECT name FROM sqlite_master WHERE type = 'table' AND name = @name;",
            "MySQL" => "SELECT table_name FROM information_schema.tables WHERE table_schema = DATABASE() AND table_name = @name;",
            "PostgreSQL" => "SELECT tablename FROM pg_tables WHERE schemaname = current_schema() AND tablename = @name;",
            _ => "SELECT 1 WHERE 1 = 0;"
        };

        var result = await connection.ExecuteScalarAsync<string?>(
            new CommandDefinition(sql, new { name = tableName }, transaction, cancellationToken: cancellationToken)
        );

        return result is not null;
    }

    public static Task RenameTableAsync(
        IDbConnection connection,
        ISqlDialect dialect,
        string fromTableName,
        string toTableName,
        IDbTransaction? transaction = null,
        CancellationToken cancellationToken = default)
    {
        var sql = $"ALTER TABLE {dialect.QuoteIdentifier(fromTableName)} RENAME TO {dialect.QuoteIdentifier(toTableName)};";
        return connection.ExecuteAsync(new CommandDefinition(sql, transaction: transaction, cancellationToken: cancellationToken));
    }
}