Set relations to retrieve by a query at compile time.

+ Add compile-time utility functions to build strings and queries.
* Relations to retrieve when querying a model must now be set at comptime.

src/comptime.zig

@@ -0,0 +1,33 @@
+
+/// Append an element to the given array at comptime.
+pub fn append(array: anytype, element: anytype) @TypeOf(array ++ .{element}) {
+	return array ++ .{element};
+}
+
+/// Join strings into one, with the given separator in between.
+pub fn join(separator: []const u8, slices: []const[]const u8) []const u8 {
+	if (slices.len == 0) return "";
+
+	// Compute total length of the string to make.
+	const totalLen = total: {
+		// Compute separator length.
+		var total = separator.len * (slices.len - 1);
+		// Add length of all slices.
+		for (slices) |slice| total += slice.len;
+		break :total total;
+	};
+
+	var buffer: [totalLen]u8 = undefined;
+
+	// Based on std.mem.joinMaybeZ implementation.
+	@memcpy(buffer[0..slices[0].len], slices[0]);
+	var buf_index: usize = slices[0].len;
+	for (slices[1..]) |slice| {
+		@memcpy(buffer[buf_index .. buf_index + separator.len], separator);
+		buf_index += separator.len;
+		@memcpy(buffer[buf_index .. buf_index + slice.len], slice);
+		buf_index += slice.len;
+	}
+
+	return &buffer;
+}

src/query.zig

@@ -8,25 +8,71 @@ const _sql = @import("sql.zig");
 const _conditions = @import("conditions.zig");
 const relations = @import("relations.zig");
 const repository = @import("repository.zig");
-
+const _comptime = @import("comptime.zig");
-const InlineRelationsResult = struct {
-
-};
 
 /// Repository query configuration structure.
 pub const RepositoryQueryConfiguration = struct {
 	select: ?_sql.RawQuery = null,
 	join: ?_sql.RawQuery = null,
 	where: ?_sql.RawQuery = null,
-	with: ?[]const relations.Eager = null,
+};
+
+/// Compiled relations structure.
+const CompiledRelations = struct {
+	inlineSelect: []const u8,
+	inlineJoins: []const u8,
 };
 
 /// Repository models query manager.
 /// Manage query string build and its execution.
-pub fn RepositoryQuery(comptime Model: type, comptime TableShape: type, comptime repositoryConfig: repository.RepositoryConfiguration(Model, TableShape)) type {
+pub fn RepositoryQuery(comptime Model: type, comptime TableShape: type, comptime repositoryConfig: repository.RepositoryConfiguration(Model, TableShape), comptime with: ?[]const relations.ModelRelation) type {
-	// Pre-compute SQL buffer size.
+	const compiledRelations = comptime compile: {
+		// Inline relations list.
+		var inlineRelations: []relations.ModelRelation = &[0]relations.ModelRelation{};
+
+		if (with) |_with| {
+			// If there are relations to eager load, prepare their query.
+
+			// Initialize inline select array.
+			var inlineSelect: [][]const u8 = &[0][]const u8{};
+			// Initialize inline joins array.
+			var inlineJoins: [][]const u8 = &[0][]const u8{};
+
+			for (_with) |relation| {
+				// For each relation, determine if it's inline or not.
+				var tt = relation.relation{};
+				const relationInstance = tt.relation();
+				if (relationInstance.inlineMapping()) {
+					// Add the current relation to inline relations.
+					inlineRelations = @ptrCast(@constCast(_comptime.append(inlineRelations, relation)));
+
+					// Build table alias and fields prefix for the relation.
+					const tableAlias = "relations." ++ relation.field;
+					const fieldsPrefix = tableAlias ++ ".";
+
+					// Generate selected columns for the relation.
+					inlineSelect = @ptrCast(@constCast(_comptime.append(inlineSelect, relationInstance.genSelect(tableAlias, fieldsPrefix))));
+					// Generate joined table for the relation.
+					inlineJoins = @ptrCast(@constCast(_comptime.append(inlineJoins, relationInstance.genJoin(tableAlias))));
+				}
+			}
+
+			break :compile CompiledRelations{
+				.inlineSelect = if (inlineSelect.len > 0) ", " ++ _comptime.join(", ", inlineSelect) else "",
+				.inlineJoins = if (inlineJoins.len > 0) " " ++ _comptime.join(" ", inlineJoins) else "",
+			};
+		} else {
+			break :compile CompiledRelations{
+				.inlineSelect = "",
+				.inlineJoins = "",
+			};
+		}
+	};
+
+	// Pre-compute SQL buffer.
 	const fromClause = " FROM \"" ++ repositoryConfig.table ++ "\"";
-	const defaultSelectSql = "\"" ++ repositoryConfig.table ++ "\".*";
+	const defaultSelectSql = "\"" ++ repositoryConfig.table ++ "\".*" ++ compiledRelations.inlineSelect;
+	const defaultJoin = compiledRelations.inlineJoins;
 
 	// Model key type.
 	const KeyType = repository.ModelKeyType(Model, TableShape, repositoryConfig);
@@ -39,9 +85,6 @@ pub fn RepositoryQuery(comptime Model: type, comptime TableShape: type, comptime
 		connection: *database.Connection = undefined,
 		queryConfig: RepositoryQueryConfiguration,
 
-		/// List of loaded inline relations.
-		inlineRelations: []relations.Eager = undefined,
-
 		query: ?_sql.RawQuery = null,
 		sql: ?[]const u8 = null,
 
@@ -177,103 +220,16 @@ pub fn RepositoryQuery(comptime Model: type, comptime TableShape: type, comptime
 			}
 		}
 
-		/// Set relations to eager load.
-		pub fn with(self: *Self, relation: relations.ModelRelation) !void {
-			// Take an array of eager relations (which can have subrelations).
-			const allocator = self.arena.allocator();
-
-			// Make a relation instance.
-			const relationInstance = try allocator.create(relation.relation);
-
-			// Add the new relation to a newly allocated array, with one more space.
-			const newPos = if (self.queryConfig.with) |_with| _with.len else 0;
-			var newWith = try allocator.alloc(relations.Eager, newPos + 1);
-			newWith[newPos] = .{
-				.field = relation.field,
-				.relation = relationInstance.*.relation(),
-				.with = &[0]relations.Eager{}, //TODO handle subrelations with dotted syntax
-			};
-
-			if (self.queryConfig.with) |_with| {
-				// Copy existing relations.
-				@memcpy(newWith[0..newPos], _with);
-				// Free previous array.
-				allocator.free(_with);
-			}
-
-			// Save the newly allocated array.
-			self.queryConfig.with = newWith;
-		}
-
-		/// Build inline relations query part.
-		fn buildInlineRelations(self: *Self) !?struct{
-			select: []const u8,
-			join: _sql.RawQuery,
-		} {
-			if (self.queryConfig.with) |_with| {
-				// Initialize an ArrayList of query parts for relations.
-				var inlineRelations = try std.ArrayList(_sql.RawQuery).initCapacity(self.arena.allocator(), _with.len);
-				defer inlineRelations.deinit();
-				var inlineRelationsSelect = try std.ArrayList([]const u8).initCapacity(self.arena.allocator(), _with.len);
-				defer inlineRelationsSelect.deinit();
-
-				// Initialize an ArrayList to store all loaded inline relations.
-				var loadedRelations = std.ArrayList(relations.Eager).init(self.arena.allocator());
-				defer loadedRelations.deinit();
-
-				for (_with) |_relation| {
-					// Append each inline relation to the ArrayList.
-					if (_relation.relation.inlineMapping()) {
-						try loadedRelations.append(_relation); // Store the loaded inline relation.
-
-						// Get an allocator for local allocations.
-						const localAllocator = self.arena.allocator();
-
-						// Build table alias and fields prefix.
-						const tableAlias = try std.fmt.allocPrint(localAllocator, "relations.{s}", .{_relation.field});
-						defer localAllocator.free(tableAlias);
-						const prefix = try std.fmt.allocPrint(localAllocator, "{s}.", .{tableAlias});
-						defer localAllocator.free(prefix);
-
-						// Alter query to get relation fields.
-						try inlineRelations.append(try _relation.relation.genJoin(self.arena.allocator(), tableAlias));
-						const relationSelect = try _relation.relation.genSelect(localAllocator, tableAlias, prefix);
-						try inlineRelationsSelect.append(relationSelect);
-					}
-				}
-
-				self.inlineRelations = try loadedRelations.toOwnedSlice();
-
-				// Return the inline relations query part.
-				return .{
-					.select = try std.mem.join(self.arena.allocator(), ", ", inlineRelationsSelect.items),
-					.join = try _sql.RawQuery.fromConcat(self.arena.allocator(), inlineRelations.items),
-				};
-			} else {
-				// Nothing.
-				return null;
-			}
-		}
-
 		/// Build SQL query.
 		pub fn buildSql(self: *Self) !void {
-			// Build inline relations query part.
-			const inlineRelations = try self.buildInlineRelations();
-			defer if (inlineRelations) |_inlineRelations| self.arena.allocator().free(_inlineRelations.join.sql);
-			defer if (inlineRelations) |_inlineRelations| self.arena.allocator().free(_inlineRelations.join.params);
-			defer if (inlineRelations) |_inlineRelations| self.arena.allocator().free(_inlineRelations.select);
-
 			// Build the full SQL query from all its parts.
 			const sqlQuery = _sql.RawQuery{
 				.sql = try std.mem.join(self.arena.allocator(), "", &[_][]const u8{
 					"SELECT ", if (self.queryConfig.select) |_select| _select.sql else defaultSelectSql,
-					if (inlineRelations) |_| ", " else "",
-					if (inlineRelations) |_inlineRelations| _inlineRelations.select else "",
 					fromClause,
+					defaultJoin,
 					if (self.queryConfig.join) |_| " " else "",
 					if (self.queryConfig.join) |_join| _join.sql else "",
-					if (inlineRelations) |_| " " else "",
-					if (inlineRelations) |_inlineRelations| _inlineRelations.join.sql else "",
 					if (self.queryConfig.where) |_| " WHERE " else "",
 					if (self.queryConfig.where) |_where| _where.sql else "",
 					";",
@@ -281,7 +237,6 @@ pub fn RepositoryQuery(comptime Model: type, comptime TableShape: type, comptime
 				.params = try std.mem.concat(self.arena.allocator(), _sql.RawQueryParameter, &[_][]const _sql.RawQueryParameter{
 					if (self.queryConfig.select) |_select| _select.params else &[0]_sql.RawQueryParameter{},
 					if (self.queryConfig.join) |_join| _join.params else &[0]_sql.RawQueryParameter{},
-					if (inlineRelations) |_inlineRelations| _inlineRelations.join.params else &[0]_sql.RawQueryParameter{},
 					if (self.queryConfig.where) |_where| _where.params else &[0]_sql.RawQueryParameter{},
 				})
 			};

src/relations.zig

@@ -62,8 +62,7 @@ pub fn typedMany(
 	};
 
 	const FromKeyType = std.meta.fields(FromModel)[std.meta.fieldIndex(FromModel, fromRepositoryConfig.key[0]).?].type;
-	const QueryType = _query.RepositoryQuery(ToModel, ToTable, toRepositoryConfig);
+	const QueryType = _query.RepositoryQuery(ToModel, ToTable, toRepositoryConfig, null);
-	const SelectBuilder = _sql.SelectBuilder(ToTable);
 
 	return struct {
 		const Self = @This();
@@ -72,12 +71,12 @@ pub fn typedMany(
 			return false;
 		}
 
-		fn genJoin(_: *anyopaque, _: std.mem.Allocator, _: []const u8) !_sql.RawQuery {
+		fn genJoin(_: *anyopaque, comptime _: []const u8) []const u8 {
 			unreachable; // No possible join in a many relation.
 		}
 
-		fn genSelect(_: *anyopaque, allocator: std.mem.Allocator, table: []const u8, prefix: []const u8) ![]const u8 {
+		fn genSelect(_: *anyopaque, comptime table: []const u8, comptime prefix: []const u8) []const u8 {
-			return SelectBuilder.build(allocator, table, prefix);
+			return _sql.SelectBuild(ToTable, table, prefix);
 		}
 
 		fn buildQuery(_: *anyopaque, opaqueModels: []const anyopaque, opaqueQuery: *anyopaque) !void {
@@ -181,8 +180,7 @@ fn typedOne(
 	comptime config: OneConfiguration) type {
 
 	const FromKeyType = std.meta.fields(FromModel)[std.meta.fieldIndex(FromModel, fromRepositoryConfig.key[0]).?].type;
-	const QueryType = _query.RepositoryQuery(ToModel, ToTable, toRepositoryConfig);
+	const QueryType = _query.RepositoryQuery(ToModel, ToTable, toRepositoryConfig, null);
-	const SelectBuilder = _sql.SelectBuilder(ToTable);
 
 	// Get foreign key from relation config or repository config.
 	const foreignKey = switch (config) {
@@ -205,32 +203,29 @@ fn typedOne(
 			return true;
 		}
 
-		fn genJoin(_: *anyopaque, allocator: std.mem.Allocator, alias: []const u8) !_sql.RawQuery {
+		fn genJoin(_: *anyopaque, comptime alias: []const u8) []const u8 {
 			return switch (config) {
-				.direct => (.{
+				.direct => (
-					.sql = try std.fmt.allocPrint(allocator, "LEFT JOIN \"" ++ toRepositoryConfig.table ++ "\" AS \"{s}\" ON " ++
+					"LEFT JOIN \"" ++ toRepositoryConfig.table ++ "\" AS \"" ++ alias ++ "\" ON " ++
-						"\"" ++ fromRepositoryConfig.table ++ "\"." ++ foreignKey ++ " = \"{s}\"." ++ modelKey, .{alias, alias}),
+						"\"" ++ fromRepositoryConfig.table ++ "\"." ++ foreignKey ++ " = \"" ++ alias ++ "\"." ++ modelKey
-					.params = &[0]_sql.RawQueryParameter{},
+				),
-				}),
 
-				.reverse => (.{
+				.reverse => (
-					.sql = try std.fmt.allocPrint(allocator, "LEFT JOIN \"" ++ toRepositoryConfig.table ++ "\" AS \"{s}\" ON " ++
+					"LEFT JOIN \"" ++ toRepositoryConfig.table ++ "\" AS \"" ++ alias ++ "\" ON " ++
-						"\"" ++ fromRepositoryConfig.table ++ "\"." ++ modelKey ++ " = \"{s}\"." ++ foreignKey, .{alias, alias}),
+						"\"" ++ fromRepositoryConfig.table ++ "\"." ++ modelKey ++ " = \"" ++ alias ++ "\"." ++ foreignKey
-					.params = &[0]_sql.RawQueryParameter{},
+				),
-				}),
 
-				.through => |through| (.{
+				.through => |through| (
-					.sql = try std.fmt.allocPrint(allocator, "LEFT JOIN \"" ++ through.table ++ "\" AS \"{s}_pivot\" ON " ++
+					"LEFT JOIN \"" ++ through.table ++ "\" AS \"" ++ alias ++ "_pivot\" ON " ++
-						"\"" ++ fromRepositoryConfig.table ++ "\"." ++ foreignKey ++ " = " ++ "\"{s}_pivot\"." ++ through.joinForeignKey ++
+						"\"" ++ fromRepositoryConfig.table ++ "\"." ++ foreignKey ++ " = " ++ "\"" ++ alias ++ "_pivot\"." ++ through.joinForeignKey ++
-						"LEFT JOIN \"" ++ toRepositoryConfig.table ++ "\" AS \"{s}\" ON " ++
+					"LEFT JOIN \"" ++ toRepositoryConfig.table ++ "\" AS \"" ++ alias ++ "\" ON " ++
-						"\"{s}_pivot\"." ++ through.joinModelKey ++ " = " ++ "\"{s}\"." ++ modelKey, .{alias, alias, alias, alias, alias}),
+						"\"" ++ alias ++ "_pivot\"." ++ through.joinModelKey ++ " = " ++ "\"" ++ alias ++ "\"." ++ modelKey
-					.params = &[0]_sql.RawQueryParameter{},
+				),
-				}),
 			};
 		}
 
-		fn genSelect(_: *anyopaque, allocator: std.mem.Allocator, table: []const u8, prefix: []const u8) ![]const u8 {
+		fn genSelect(_: *anyopaque, comptime table: []const u8, comptime prefix: []const u8) []const u8 {
-			return SelectBuilder.build(allocator, table, prefix);
+			return _sql.SelectBuild(ToTable, table, prefix);
 		}
 
 		fn buildQuery(_: *anyopaque, opaqueModels: []const anyopaque, opaqueQuery: *anyopaque) !void {
@@ -296,8 +291,8 @@ pub const Relation = struct {
 		instance: *anyopaque,
 
 		inlineMapping: *const fn (self: *anyopaque) bool,
-		genJoin: *const fn (self: *anyopaque, allocator: std.mem.Allocator, alias: []const u8) anyerror!_sql.RawQuery,
+		genJoin: *const fn (self: *anyopaque, comptime alias: []const u8) []const u8,
-		genSelect: *const fn (self: *anyopaque, allocator: std.mem.Allocator, table: []const u8, prefix: []const u8) anyerror![]const u8,
+		genSelect: *const fn (self: *anyopaque, comptime table: []const u8, comptime prefix: []const u8) []const u8,
 		buildQuery: *const fn (self: *anyopaque, models: []const anyopaque, query: *anyopaque) anyerror!void,
 	},
 
@@ -308,13 +303,13 @@ pub const Relation = struct {
 	}
 
 	/// In case of inline mapping, generate a JOIN clause to retrieve the associated data.
-	pub fn genJoin(self: Self, allocator: std.mem.Allocator, alias: []const u8) !_sql.RawQuery {
+	pub fn genJoin(self: Self, comptime alias: []const u8) []const u8 {
-		return self._interface.genJoin(self._interface.instance, allocator, alias);
+		return self._interface.genJoin(self._interface.instance, alias);
 	}
 
 	/// Generate a SELECT clause to retrieve the associated data, with the given table and prefix.
-	pub fn genSelect(self: Self, allocator: std.mem.Allocator, table: []const u8, prefix: []const u8) ![]const u8 {
+	pub fn genSelect(self: Self, comptime table: []const u8, comptime prefix: []const u8) []const u8 {
-		return self._interface.genSelect(self._interface.instance, allocator, table, prefix);
+		return self._interface.genSelect(self._interface.instance, table, prefix);
 	}
 
 	/// Build the query to retrieve relation data.

src/repository.zig

@@ -110,7 +110,7 @@ pub fn Repository(comptime Model: type, comptime TableShape: type, comptime repo
 		pub const TableType = TableShape;
 		pub const config = repositoryConfig;
 
-		pub const Query: type = query.RepositoryQuery(Model, TableShape, config);
+		pub const Query: type = query.RepositoryQuery(Model, TableShape, config, null);
 		pub const Insert: type = insert.RepositoryInsert(Model, TableShape, config, config.insertShape);
 
 		/// Type of one model key.
@@ -152,6 +152,10 @@ pub fn Repository(comptime Model: type, comptime TableShape: type, comptime repo
 			}
 		};
 
+		pub fn QueryWith(comptime with: []const _relations.ModelRelation) type {
+			return query.RepositoryQuery(Model, TableShape, config, with);
+		}
+
 		pub fn InsertCustom(comptime InsertShape: type) type {
 			return insert.RepositoryInsert(Model, TableShape, config, InsertShape);
 		}

src/sql.zig

@@ -213,6 +213,29 @@ pub fn SelectBuilder(comptime TableShape: type) type {
 	};
 }
 
+/// Build a SELECT query part for a given table, renaming columns with the given prefix, at comptime.
+pub fn SelectBuild(comptime TableShape: type, comptime table: []const u8, comptime prefix: []const u8) []const u8 {
+	// Initialize the selected columns string.
+	var columnsSelect: []const u8 = "";
+
+	var first = true;
+	// For each field, generate a format string.
+	for (@typeInfo(TableShape).Struct.fields) |field| {
+		// Add ", " between all selected columns (just not the first one).
+		if (first) {
+			first = false;
+		} else {
+			columnsSelect = @ptrCast(columnsSelect ++ ", ");
+		}
+
+		// Select the current field column.
+		columnsSelect = @ptrCast(columnsSelect ++ "\"" ++ table ++ "\".\"" ++ field.name ++ "\" AS \"" ++ prefix ++ field.name ++ "\"");
+	}
+
+	// Return built columns selection.
+	return columnsSelect;
+}
+
 
 
 

tests/relations.zig

@@ -32,10 +32,11 @@ test "belongsTo" {
 	};
 
 	// Build a query of submodels.
-	var myQuery = repository.MySubmodelRepository.Query.init(std.testing.allocator, poolConnector.connector(), .{});
+	var myQuery = repository.MySubmodelRepository.QueryWith(
+		// Retrieve parents of submodels from relation.
+		&[_]zrm.relations.ModelRelation{repository.MySubmodelRelations.parent}
+	).init(std.testing.allocator, poolConnector.connector(), .{});
 	defer myQuery.deinit();
-	// Retrieve parents of submodels from relation.
-	try myQuery.with(repository.MySubmodelRelations.parent);
 
 	try myQuery.buildSql();