Work in progress for RepoDb offset paging, but BatchQuery is not work…

…ing as originally thought, will have to re-factor to implement a Skip/Take query manually!

GraphQL.RepoDb.SqlServer/GraphQLRepoDbMapper.cs

@@ -194,7 +194,12 @@ public RepoDbOffsetPagingParams GetOffsetPagingParameters()
                 return null;
             }
 
-            return RepoDbOffsetPagingParams.FromSkipTake(graphQLPagingArgs.Skip, graphQLPagingArgs.Take);
+
+            return RepoDbOffsetPagingParams.FromSkipTake(
+                graphQLPagingArgs.Skip, 
+                graphQLPagingArgs.Take,
+                this.GraphQLParamsContext.IsTotalCountRequested
+            );
         }
     }
 }

GraphQL.RepoDb.SqlServer/RepoDb.OffsetPagination/IRepoDbOffsetPagingParams.cs

@@ -4,5 +4,6 @@ public interface IRepoDbOffsetPagingParams
     {
         int Page { get; }
         int RowsPerBatch { get; }
+        bool IsTotalCountEnabled { get; }
     }
 }

GraphQL.RepoDb.SqlServer/RepoDb.OffsetPagination/RepoDbBatchQueryExtensions.cs

@@ -11,7 +11,7 @@
 using System.Threading.Tasks;
 using RepoDb.Interfaces;
 
-namespace RepoDb.CursorPagination
+namespace RepoDb.OffsetPagination
 {
     public static class BaseRepositoryOffsetPaginationCustomExtensions
     {
@@ -25,6 +25,7 @@ public static class BaseRepositoryOffsetPaginationCustomExtensions
         /// <param name="where"></param>
         /// <param name="page"></param>
         /// <param name="rowsPerBatch"></param>
+        /// <param name="fetchTotalCount"></param>
         /// <param name="tableName"></param>
         /// <param name="hints"></param>
         /// <param name="fields"></param>
@@ -40,6 +41,7 @@ public static async Task<OffsetPageResults<TEntity>> GraphQLBatchOffsetPagingQue
             Expression<Func<TEntity, bool>> where,
             int? page = null,
             int? rowsPerBatch = null,
+            bool fetchTotalCount = false,
             string tableName = null,
             string hints = null,
             IEnumerable<Field> fields = null,
@@ -55,6 +57,7 @@ public static async Task<OffsetPageResults<TEntity>> GraphQLBatchOffsetPagingQue
             return await baseRepo.GraphQLBatchOffsetPagingQueryAsync<TEntity, TDbConnection>(
                     page: page,
                     rowsPerBatch: rowsPerBatch,
+                    fetchTotalCount: fetchTotalCount,
                     orderBy: orderBy,
                     where: where != null ? QueryGroup.Parse<TEntity>(where) : (QueryGroup)null,
                     hints: hints,
@@ -78,6 +81,7 @@ public static async Task<OffsetPageResults<TEntity>> GraphQLBatchOffsetPagingQue
         /// <param name="page"></param>
         /// <param name="rowsPerBatch"></param>
         /// <param name="tableName"></param>
+        /// <param name="fetchTotalCount"></param>
         /// <param name="hints"></param>
         /// <param name="fields"></param>
         /// <param name="commandTimeout"></param>
@@ -91,6 +95,7 @@ public static async Task<OffsetPageResults<TEntity>> GraphQLBatchOffsetPagingQue
             QueryGroup where = null,
             int? page = null,
             int? rowsPerBatch = null,
+            bool fetchTotalCount = false,
             string hints = null,
             IEnumerable<Field> fields = null,
             string tableName = null,
@@ -111,6 +116,7 @@ public static async Task<OffsetPageResults<TEntity>> GraphQLBatchOffsetPagingQue
                 var cursorPageResult = await connection.GraphQLBatchOffsetPagingQueryAsync<TEntity>(
                     page: page,
                     rowsPerBatch: rowsPerBatch,
+                    fetchTotalCount: fetchTotalCount,
                     orderBy: orderBy,
                     where: where,
                     hints: hints,
@@ -145,6 +151,7 @@ public static async Task<OffsetPageResults<TEntity>> GraphQLBatchOffsetPagingQue
         /// <param name="where"></param>
         /// <param name="page"></param>
         /// <param name="rowsPerBatch"></param>
+        /// <param name="fetchTotalCount"></param>
         /// <param name="hints"></param>
         /// <param name="fields"></param>
         /// <param name="commandTimeout"></param>
@@ -159,6 +166,7 @@ public static async Task<OffsetPageResults<TEntity>> GraphQLBatchOffsetPagingQue
             Expression<Func<TEntity, bool>> where,
             int? page = null,
             int? rowsPerBatch = null,
+            bool fetchTotalCount = false,
             string hints = null,
             IEnumerable<Field> fields = null,
             int? commandTimeout = null,
@@ -172,6 +180,7 @@ public static async Task<OffsetPageResults<TEntity>> GraphQLBatchOffsetPagingQue
             return await dbConnection.GraphQLBatchOffsetPagingQueryAsync<TEntity>(
                 page: page,
                 rowsPerBatch: rowsPerBatch,
+                fetchTotalCount: fetchTotalCount,
                 orderBy: orderBy,
                 where: where != null ? QueryGroup.Parse<TEntity>(where) : (QueryGroup)null,
                 hints: hints,
@@ -193,6 +202,7 @@ public static async Task<OffsetPageResults<TEntity>> GraphQLBatchOffsetPagingQue
         /// <param name="page"></param>
         /// <param name="rowsPerBatch"></param>
         /// <param name="tableName"></param>
+        /// <param name="fetchTotalCount"></param>
         /// <param name="hints"></param>
         /// <param name="fields"></param>
         /// <param name="commandTimeout"></param>
@@ -206,6 +216,7 @@ public static async Task<OffsetPageResults<TEntity>> GraphQLBatchOffsetPagingQue
             QueryGroup where = null, 
             int? page = null, 
             int? rowsPerBatch = null,
+            bool fetchTotalCount = false,
             string hints = null,
             IEnumerable<Field> fields = null,
             string tableName = null,
@@ -242,10 +253,14 @@ public static async Task<OffsetPageResults<TEntity>> GraphQLBatchOffsetPagingQue
                 ? RepoDbQueryGroupProxy.GetMappedParamsObject<TEntity>(where)
                 : null;
 
-            var batchResults = await dbConnection.BatchQueryAsync<TEntity>(
-                tableName: tableName,
+            //We increment Rows count to actually be fetched by One to help determine if there is any data after the current page...
+            var rowsPerPage = rowsPerBatch ?? int.MaxValue;
+            var rowsToFetch = rowsPerPage < int.MaxValue ? rowsPerPage + 1 : rowsPerPage;
+
+            var batchResults = (await dbConnection.BatchQueryAsync<TEntity>(
+                tableName: dbTableName,
                 page: page ?? 0,
-                rowsPerBatch: rowsPerBatch ?? int.MaxValue,
+                rowsPerBatch: rowsToFetch,
                 fields: validSelectFields,
                 orderBy: orderBy,
                 where: whereParams,
@@ -254,10 +269,34 @@ public static async Task<OffsetPageResults<TEntity>> GraphQLBatchOffsetPagingQue
                 transaction: transaction,
                 trace: trace,
                 cancellationToken: cancellationToken
-            ).ConfigureAwait(false);
+            ).ConfigureAwait(false))
+            ?.ToList() ?? new List<TEntity>();
+
+            //If specified we need to get the Total Count...
+            int totalCount = 0;
+            if (fetchTotalCount)
+            {
+                var repoDbTotalCount = await dbConnection.CountAsync(
+                    tableName: dbTableName,
+                    where: whereParams,
+                    hints: hints,
+                    commandTimeout: commandTimeout,
+                    transaction: transaction,
+                    trace: trace,
+                    cancellationToken: cancellationToken
+                ).ConfigureAwait(false);
+
+                totalCount = Convert.ToInt32(repoDbTotalCount);
+            }
 
             //TODO: Implement Logic to determine HasNextPage, HasPreviousPage, and get Total Count or Not!
-            var offsetPageResults = new OffsetPageResults<TEntity>(batchResults, true, true, 0);
+            var hasPreviousPage = page > 0;
+            var hasNextPage = batchResults.Count > rowsPerPage;
+
+            //Trim the results to the exact page size (removing potential additional item).
+            var pageResults = batchResults.Take(rowsPerPage);
+
+            var offsetPageResults = new OffsetPageResults<TEntity>(pageResults, hasNextPage, hasPreviousPage, totalCount);
             return offsetPageResults;
         }
 

GraphQL.RepoDb.SqlServer/RepoDb.OffsetPagination/RepoDbOffsetPagingParams.cs

@@ -17,13 +17,15 @@ public class RepoDbOffsetPagingParams : IRepoDbOffsetPagingParams
         /// </summary>
         /// <param name="rowsPerBatch">Is Optional and may be null to get all results; will default to getting all data (int.MaxValue) if null or is not a valid positive value.</param>
         /// <param name="page">Is Optional and will default to the first page (zero-based) if null or is not a valid positive value.</param>
-        public RepoDbOffsetPagingParams(int? rowsPerBatch = null, int? page = null)
+        /// <param name="fetchTotalCount">Enable the retrieval of the Total Count; for OffsetPaging this is optional and enabling it may impact performance.</param>
+        public RepoDbOffsetPagingParams(int? rowsPerBatch = null, int? page = null, bool fetchTotalCount = false)
         {
             if (rowsPerBatch.HasValue && rowsPerBatch <= 0)
                 throw new ArgumentException("A valid number of rows per batch must be specified (>0).", nameof(rowsPerBatch));
 
             this.RowsPerBatch = rowsPerBatch.HasValue && rowsPerBatch > 0 ? (int)rowsPerBatch : int.MaxValue;
             this.Page = page.HasValue && page > 0 ? (int)page : 0;
+            this.IsTotalCountEnabled = fetchTotalCount;
         }
 
         /// <summary>
@@ -32,8 +34,9 @@ public RepoDbOffsetPagingParams(int? rowsPerBatch = null, int? page = null)
         /// </summary>
         /// <param name="skip">Is Optional and may be null to get all results; will default to skipping none (0) if null or is not a valid positive value.</param>
         /// <param name="take">Is Optional and may be null to get all results; will default to getting all data (int.MaxValue) if null or is not a valid positive value.</param>
+        /// <param name="fetchTotalCount">Enable the retrieval of the Total Count; for OffsetPaging this is optional and enabling it may impact performance.</param>
         /// <returns></returns>
-        public static RepoDbOffsetPagingParams FromSkipTake(int? skip = null, int? take = null)
+        public static RepoDbOffsetPagingParams FromSkipTake(int? skip = null, int? take = null, bool fetchTotalCount = false)
         {
             if (take.HasValue && take <= 0)
                 throw new ArgumentException("A valid number of items to take (rows-per-page) must be specified (e.g. greater than 0).", nameof(take));
@@ -48,10 +51,11 @@ public static RepoDbOffsetPagingParams FromSkipTake(int? skip = null, int? take
             var skipOver = Math.Max((skip ?? 0), 0);
             var page = (int)(skipOver / rowsPerBatch);
 
-            return new RepoDbOffsetPagingParams(rowsPerBatch, page);
+            return new RepoDbOffsetPagingParams(rowsPerBatch, page, fetchTotalCount);
         }
 
         public int Page { get; }
         public int RowsPerBatch { get; }
+        public bool IsTotalCountEnabled { get; }
     }
 }

Sample.StarWars-AzureFunctions-RepoDB/Characters/CharacterQueries.cs

@@ -55,7 +55,7 @@ [GraphQLParams] IParamsContext graphQLParams
             //       down to the Repository (and underlying Database) layer.
             var charactersSlice = await repository.GetCursorPagedCharactersAsync(
                 repoDbParams.GetSelectFields(),
-                repoDbParams.GetSortOrderFields() ?? OrderField.Parse(new { Name = Order.Ascending }),
+                repoDbParams.GetSortOrderFields(),
                 repoDbParams.GetCursorPagingParameters()
             );
 
@@ -91,7 +91,7 @@ [GraphQLParams] IParamsContext graphQLParams
             //       down to the Repository (and underlying Database) layer.
             var charactersPage = await repository.GetOffsetPagedCharactersAsync(
                 repoDbParams.GetSelectFields(),
-                repoDbParams.GetSortOrderFields() ?? OrderField.Parse(new { Name = Order.Ascending }),
+                repoDbParams.GetSortOrderFields(),
                 repoDbParams.GetOffsetPagingParameters()
             );
 

Sample.StarWars-AzureFunctions-RepoDB/Repositories/CharacterRepository.cs

@@ -9,19 +9,20 @@
 using HotChocolate.PreProcessingExtensions.Pagination;
 using Microsoft.Data.SqlClient;
 using RepoDb;
-using RepoDb.CursorPagination;
 using RepoDb.Enumerations;
+using RepoDb.CursorPagination;
+using RepoDb.OffsetPagination;
 using StarWars.Characters;
 using StarWars.Characters.DbModels;
 
 namespace StarWars.Repositories
 {
     public class CharacterRepository : BaseRepository<ICharacter, SqlConnection>, ICharacterRepository
     {
-        public static class TableNames
+        public static readonly IReadOnlyList<OrderField> DefaultCharacterSortFields = new List<OrderField>()
         {
-            public const string StarWarsCharacters = "StarWarsCharacters";
-        }
+            OrderField.Ascending<ICharacter>(c => c.Id)
+        }.AsReadOnly();
 
         public CharacterRepository(string connectionString)
             : base(connectionString)
@@ -38,7 +39,7 @@ IEnumerable<OrderField> sortFields
             var results = await sqlConn.QueryAsync<CharacterDbModel>(
                 where: c => c.Id >= 1000 && c.Id <=2999,
                 fields: selectFields,
-                orderBy: sortFields
+                orderBy: sortFields ?? DefaultCharacterSortFields
             );
 
             var mappedResults = MapDbModelsToCharacterModels(results);
@@ -56,7 +57,7 @@ IRepoDbCursorPagingParams pagingParams
 
             var pageSlice = await sqlConn.GraphQLBatchSliceQueryAsync<CharacterDbModel>(
                 fields: selectFields,
-                orderBy: sortFields,
+                orderBy: sortFields ?? DefaultCharacterSortFields,
                 afterCursor: pagingParams.AfterIndex!,
                 beforeCursor: pagingParams.BeforeIndex!,
                 firstTake: pagingParams.First,
@@ -80,7 +81,8 @@ IRepoDbOffsetPagingParams pagingParams
             var offsetPageResults = await sqlConn.GraphQLBatchOffsetPagingQueryAsync<CharacterDbModel>(
                 page: pagingParams.Page,
                 rowsPerBatch: pagingParams.RowsPerBatch,
-                orderBy: sortFields,
+                fetchTotalCount: pagingParams.IsTotalCountEnabled,
+                orderBy: sortFields ?? DefaultCharacterSortFields,
                 fields: selectFields
             );
 
@@ -97,7 +99,7 @@ IRepoDbCursorPagingParams pagingParams
             await using var sqlConn = CreateConnection();
 
             var pageSlice = await sqlConn.GraphQLBatchSliceQueryAsync<CharacterDbModel>(
-                orderBy: sortFields,
+                orderBy: sortFields ?? DefaultCharacterSortFields,
                 fields: selectFields,
                 where: c => c.Id >=1000 && c.Id <= 1999,
                 afterCursor: pagingParams.AfterIndex!,

Temp/RepoDB Batch Offset Paging Tests.sql

@@ -0,0 +1,13 @@
+SELECT * FROM StarWarsCharacters ORDER BY Id ASC
+
+DECLARE @page AS INT = 1;
+DECLARE @rowsPerBatch AS INT = 8;
+
+SELECT TOP((@page + 1)*@rowsPerBatch) ROW_NUMBER() OVER (ORDER BY Id ASC) AS [RowNumber], [Id], [Name] FROM [StarWarsCharacters] ORDER BY Id ASC;
+
+--Modeled from RepoDB's BatchQuery logic (query builder)
+WITH CTE AS (SELECT TOP((@page + 1)*@rowsPerBatch) ROW_NUMBER() OVER (ORDER BY Id ASC) AS [RowNumber], [Id], [Name] FROM [StarWarsCharacters] ORDER BY Id ASC)
+SELECT [Id], [Name] FROM CTE WHERE ([RowNumber] BETWEEN ((@page * @rowsPerBatch) + 1) AND ((@page + 1) * @rowsPerBatch));
+
+SELECT
+	BetweenSql = 'Between ' + CONVERT(VARCHAR(5), ((@page * @rowsPerBatch) + 1)) + ' and ' + CONVERT(VARCHAR(5), ((@page + 1) * @rowsPerBatch));