Umbraco-CMS/src/Umbraco.Infrastructure/Persistence/UmbracoDatabaseExtensions.cs

using System;
using System.Collections.Generic;
using System.Linq;
using Umbraco.Cms.Infrastructure.Persistence.Dtos;
using Umbraco.Cms.Infrastructure.Persistence.SqlSyntax;
using Umbraco.Extensions;

namespace Umbraco.Cms.Infrastructure.Persistence
{
    internal static class UmbracoDatabaseExtensions
    {
        public static UmbracoDatabase AsUmbracoDatabase(this IUmbracoDatabase database)
        {
            if (database is not UmbracoDatabase asDatabase)
            {
                throw new Exception("oops: database.");
            }

            return asDatabase;
        }

        /// <summary>
        /// Gets a dictionary of key/values directly from the database, no scope, nothing.
        /// </summary>
        /// <remarks>Used by <see cref="CoreRuntimeBootstrapper"/> to determine the runtime state.</remarks>
        public static IReadOnlyDictionary<string, string> GetFromKeyValueTable(this IUmbracoDatabase database, string keyPrefix)
        {
            if (database is null) return null;

            // create the wildcard where clause
            ISqlSyntaxProvider sqlSyntax = database.SqlContext.SqlSyntax;
            var whereParam = sqlSyntax.GetStringColumnWildcardComparison(
                sqlSyntax.GetQuotedColumnName("key"),
                0,
                Querying.TextColumnType.NVarchar);

            var sql = database.SqlContext.Sql()
                .Select<KeyValueDto>()
                .From<KeyValueDto>()
                .Where(whereParam, keyPrefix + sqlSyntax.GetWildcardPlaceholder());

            return database.Fetch<KeyValueDto>(sql)
                .ToDictionary(x => x.Key, x => x.Value);
        }


        /// <summary>
        /// Returns true if the database contains the specified table
        /// </summary>
        /// <param name="database"></param>
        /// <param name="tableName"></param>
        /// <returns></returns>
        public static bool HasTable(this IUmbracoDatabase database, string tableName)
        {
            try
            {
                return database.SqlContext.SqlSyntax.GetTablesInSchema(database).Any(table => table.InvariantEquals(tableName));
            }
            catch (Exception)
            {
                return false; // will occur if the database cannot connect
            }
        }

        /// <summary>
        /// Returns true if the database contains no tables
        /// </summary>
        /// <param name="database"></param>
        /// <returns></returns>
        public static bool IsDatabaseEmpty(this IUmbracoDatabase database)
            => database.SqlContext.SqlSyntax.GetTablesInSchema(database).Any() == false;

    }
}