improve string library usage in the database libraries

modules/postgres/postgres.lua

@@ -23,24 +23,19 @@ function Connection:query(query_str, ...)
 	if not self._id then
 		error("Connection is closed")
 	end
-	query_str = string.normalize_whitespace(query_str)
+	return moonshark.sql_query(self._id, query_str:normalize_whitespace(), ...)
-	return moonshark.sql_query(self._id, query_str, ...)
 end
 
 function Connection:exec(query_str, ...)
 	if not self._id then
 		error("Connection is closed")
 	end
-	query_str = string.normalize_whitespace(query_str)
+	return moonshark.sql_exec(self._id, query_str:normalize_whitespace(), ...)
-	return moonshark.sql_exec(self._id, query_str, ...)
 end
 
 function Connection:query_row(query_str, ...)
 	local results = self:query(query_str, ...)
-	if results and #results > 0 then
+	return results and #results > 0 and results[1] or nil
-		return results[1]
-	end
-	return nil
 end
 
 function Connection:query_value(query_str, ...)
@@ -53,77 +48,50 @@ function Connection:query_value(query_str, ...)
 	return nil
 end
 
--- Enhanced transaction support with savepoints
 function Connection:begin()
 	local result = self:exec("BEGIN")
 	if result then
 		return {
 			conn = self,
 			active = true,
-
 			commit = function(tx)
 				if tx.active then
-					local result = tx.conn:exec("COMMIT")
 					tx.active = false
-					return result
+					return tx.conn:exec("COMMIT")
 				end
 				return false
 			end,
-
 			rollback = function(tx)
 				if tx.active then
-					local result = tx.conn:exec("ROLLBACK")
 					tx.active = false
-					return result
+					return tx.conn:exec("ROLLBACK")
 				end
 				return false
 			end,
-
 			savepoint = function(tx, name)
-				if not tx.active then
+				if not tx.active then error("Transaction is not active") end
-					error("Transaction is not active")
+				if name:is_blank() then error("Savepoint name cannot be empty") end
-				end
+				return tx.conn:exec("SAVEPOINT {{name}}":parse({name = name}))
-				if string.is_blank(name) then
-					error("Savepoint name cannot be empty")
-				end
-				return tx.conn:exec(string.template("SAVEPOINT ${name}", {name = name}))
 			end,
-
 			rollback_to = function(tx, name)
-				if not tx.active then
+				if not tx.active then error("Transaction is not active") end
-					error("Transaction is not active")
+				if name:is_blank() then error("Savepoint name cannot be empty") end
-				end
+				return tx.conn:exec("ROLLBACK TO SAVEPOINT {{name}}":parse({name = name}))
-				if string.is_blank(name) then
-					error("Savepoint name cannot be empty")
-				end
-				return tx.conn:exec(string.template("ROLLBACK TO SAVEPOINT ${name}", {name = name}))
 			end,
-
 			query = function(tx, query_str, ...)
-				if not tx.active then
+				if not tx.active then error("Transaction is not active") end
-					error("Transaction is not active")
-				end
 				return tx.conn:query(query_str, ...)
 			end,
-
 			exec = function(tx, query_str, ...)
-				if not tx.active then
+				if not tx.active then error("Transaction is not active") end
-					error("Transaction is not active")
-				end
 				return tx.conn:exec(query_str, ...)
 			end,
-
 			query_row = function(tx, query_str, ...)
-				if not tx.active then
+				if not tx.active then error("Transaction is not active") end
-					error("Transaction is not active")
-				end
 				return tx.conn:query_row(query_str, ...)
 			end,
-
 			query_value = function(tx, query_str, ...)
-				if not tx.active then
+				if not tx.active then error("Transaction is not active") end
-					error("Transaction is not active")
-				end
 				return tx.conn:query_value(query_str, ...)
 			end
 		}
@@ -131,38 +99,34 @@ function Connection:begin()
 	return nil
 end
 
--- Simplified PostgreSQL parameter builder
+-- Build PostgreSQL parameters ($1, $2, etc.)
 local function build_postgres_params(data)
 	local keys = table.keys(data)
 	local values = table.values(data)
 	local placeholders = {}
 
 	for i = 1, #keys do
-		table.insert(placeholders, string.template("$${num}", {num = tostring(i)}))
+		placeholders[i] = "$" .. i
 	end
 
-	return keys, values, placeholders, #keys
+	return keys, values, placeholders
 end
 
--- Simplified query builders using table utilities
 function Connection:insert(table_name, data, returning)
-	if string.is_blank(table_name) then
+	if table_name:is_blank() then
 		error("Table name cannot be empty")
 	end
 
 	local keys, values, placeholders = build_postgres_params(data)
 
-	local query = string.template("INSERT INTO ${table} (${columns}) VALUES (${placeholders})", {
+	local query = "INSERT INTO {{table}} ({{columns}}) VALUES ({{placeholders}})":parse({
 		table = table_name,
-		columns = table.concat(keys, ", "),
+		columns = keys:join(", "),
 		placeholders = table.concat(placeholders, ", ")
 	})
 
-	if returning and not string.is_blank(returning) then
+	if returning and not returning:is_blank() then
-		query = string.template("${query} RETURNING ${returning}", {
+		query = query .. " RETURNING " .. returning
-			query = query,
-			returning = returning
-		})
 		return self:query(query, unpack(values))
 	else
 		return self:exec(query, unpack(values))
@@ -170,37 +134,32 @@ function Connection:insert(table_name, data, returning)
 end
 
 function Connection:upsert(table_name, data, conflict_columns, returning)
-	if string.is_blank(table_name) then
+	if table_name:is_blank() then
 		error("Table name cannot be empty")
 	end
 
 	local keys, values, placeholders = build_postgres_params(data)
-	local updates = table.map(keys, function(key)
+	local updates = table.map(keys, function(key) return key .. " = EXCLUDED." .. key end)
-		return string.template("${key} = EXCLUDED.${key}", {key = key})
-	end)
 
 	local conflict_clause = ""
 	if conflict_columns then
 		if type(conflict_columns) == "string" then
-			conflict_clause = string.template("(${columns})", {columns = conflict_columns})
+			conflict_clause = "(" .. conflict_columns .. ")"
 		else
-			conflict_clause = string.template("(${columns})", {columns = table.concat(conflict_columns, ", ")})
+			conflict_clause = "(" .. table.concat(conflict_columns, ", ") .. ")"
 		end
 	end
 
-	local query = string.template("INSERT INTO ${table} (${columns}) VALUES (${placeholders}) ON CONFLICT ${conflict} DO UPDATE SET ${updates}", {
+	local query = "INSERT INTO {{table}} ({{columns}}) VALUES ({{placeholders}}) ON CONFLICT {{conflict}} DO UPDATE SET {{updates}}":parse({
 		table = table_name,
-		columns = table.concat(keys, ", "),
+		columns = keys:join(", "),
 		placeholders = table.concat(placeholders, ", "),
 		conflict = conflict_clause,
-		updates = table.concat(updates, ", ")
+		updates = updates:join(", ")
 	})
 
-	if returning and not string.is_blank(returning) then
+	if returning and not returning:is_blank() then
-		query = string.template("${query} RETURNING ${returning}", {
+		query = query .. " RETURNING " .. returning
-			query = query,
-			returning = returning
-		})
 		return self:query(query, unpack(values))
 	else
 		return self:exec(query, unpack(values))
@@ -208,10 +167,10 @@ function Connection:upsert(table_name, data, conflict_columns, returning)
 end
 
 function Connection:update(table_name, data, where_clause, returning, ...)
-	if string.is_blank(table_name) then
+	if table_name:is_blank() then
 		error("Table name cannot be empty")
 	end
-	if string.is_blank(where_clause) then
+	if where_clause:is_blank() then
 		error("WHERE clause cannot be empty for UPDATE")
 	end
 
@@ -219,35 +178,29 @@ function Connection:update(table_name, data, where_clause, returning, ...)
 	local values = table.values(data)
 	local param_count = #keys
 
+	-- Build SET clause with numbered parameters
 	local sets = {}
 	for i, key in ipairs(keys) do
-		table.insert(sets, string.template("${key} = $${num}", {
+		sets[i] = key .. " = $" .. i
-			key = key,
-			num = tostring(i)
-		}))
 	end
 
-	-- Handle WHERE clause parameters
+	-- Handle WHERE parameters
 	local where_args = {...}
-	local where_clause_with_params = where_clause
+	local where_clause_final = where_clause
 	for i = 1, #where_args do
 		param_count = param_count + 1
-		table.insert(values, where_args[i])
+		values[#values + 1] = where_args[i]
-		where_clause_with_params = string.replace(where_clause_with_params, "?",
+		where_clause_final = where_clause_final:replace("?", "$" .. param_count, 1)
-			string.template("$${num}", {num = tostring(param_count)}), 1)
 	end
 
-	local query = string.template("UPDATE ${table} SET ${sets} WHERE ${where}", {
+	local query = "UPDATE {{table}} SET {{sets}} WHERE {{where}}":parse({
 		table = table_name,
 		sets = table.concat(sets, ", "),
-		where = where_clause_with_params
+		where = where_clause_final
 	})
 
-	if returning and not string.is_blank(returning) then
+	if returning and not returning:is_blank() then
-		query = string.template("${query} RETURNING ${returning}", {
+		query = query .. " RETURNING " .. returning
-			query = query,
-			returning = returning
-		})
 		return self:query(query, unpack(values))
 	else
 		return self:exec(query, unpack(values))
@@ -255,33 +208,29 @@ function Connection:update(table_name, data, where_clause, returning, ...)
 end
 
 function Connection:delete(table_name, where_clause, returning, ...)
-	if string.is_blank(table_name) then
+	if table_name:is_blank() then
 		error("Table name cannot be empty")
 	end
-	if string.is_blank(where_clause) then
+	if where_clause:is_blank() then
 		error("WHERE clause cannot be empty for DELETE")
 	end
 
-	-- Handle WHERE clause parameters
 	local where_args = {...}
 	local values = {}
-	local where_clause_with_params = where_clause
+	local where_clause_final = where_clause
+
 	for i = 1, #where_args do
-		table.insert(values, where_args[i])
+		values[i] = where_args[i]
-		where_clause_with_params = string.replace(where_clause_with_params, "?",
+		where_clause_final = where_clause_final:replace("?", "$" .. i, 1)
-			string.template("$${num}", {num = tostring(i)}), 1)
 	end
 
-	local query = string.template("DELETE FROM ${table} WHERE ${where}", {
+	local query = "DELETE FROM {{table}} WHERE {{where}}":parse({
 		table = table_name,
-		where = where_clause_with_params
+		where = where_clause_final
 	})
 
-	if returning and not string.is_blank(returning) then
+	if returning and not returning:is_blank() then
-		query = string.template("${query} RETURNING ${returning}", {
+		query = query .. " RETURNING " .. returning
-			query = query,
-			returning = returning
-		})
 		return self:query(query, unpack(values))
 	else
 		return self:exec(query, unpack(values))
@@ -289,7 +238,7 @@ function Connection:delete(table_name, where_clause, returning, ...)
 end
 
 function Connection:select(table_name, columns, where_clause, ...)
-	if string.is_blank(table_name) then
+	if table_name:is_blank() then
 		error("Table name cannot be empty")
 	end
 
@@ -298,26 +247,24 @@ function Connection:select(table_name, columns, where_clause, ...)
 		columns = table.concat(columns, ", ")
 	end
 
-	local query
+	if where_clause and not where_clause:is_blank() then
-	if where_clause and not string.is_blank(where_clause) then
-		-- Handle WHERE clause parameters
 		local where_args = {...}
 		local values = {}
-		local where_clause_with_params = where_clause
+		local where_clause_final = where_clause
+
 		for i = 1, #where_args do
-			table.insert(values, where_args[i])
+			values[i] = where_args[i]
-			where_clause_with_params = string.replace(where_clause_with_params, "?",
+			where_clause_final = where_clause_final:replace("?", "$" .. i, 1)
-				string.template("$${num}", {num = tostring(i)}), 1)
 		end
 
-		query = string.template("SELECT ${columns} FROM ${table} WHERE ${where}", {
+		local query = "SELECT {{columns}} FROM {{table}} WHERE {{where}}":parse({
 			columns = columns,
 			table = table_name,
-			where = where_clause_with_params
+			where = where_clause_final
 		})
 		return self:query(query, unpack(values))
 	else
-		query = string.template("SELECT ${columns} FROM ${table}", {
+		local query = "SELECT {{columns}} FROM {{table}}":parse({
 			columns = columns,
 			table = table_name
 		})
@@ -325,163 +272,137 @@ function Connection:select(table_name, columns, where_clause, ...)
 	end
 end
 
--- Enhanced PostgreSQL schema helpers
+-- Schema helpers
 function Connection:table_exists(table_name, schema_name)
-	if string.is_blank(table_name) then
+	if table_name:is_blank() then return false end
-		return false
-	end
-
 	schema_name = schema_name or "public"
-	local result = self:query_value(
+	return self:query_value("SELECT tablename FROM pg_tables WHERE schemaname = $1 AND tablename = $2",
-		"SELECT tablename FROM pg_tables WHERE schemaname = $1 AND tablename = $2",
+		schema_name:trim(), table_name:trim()) ~= nil
-		string.trim(schema_name), string.trim(table_name)
-	)
-	return result ~= nil
 end
 
 function Connection:column_exists(table_name, column_name, schema_name)
-	if string.is_blank(table_name) or string.is_blank(column_name) then
+	if table_name:is_blank() or column_name:is_blank() then return false end
-		return false
-	end
-
 	schema_name = schema_name or "public"
-	local result = self:query_value([[
+	return self:query_value([[
 		SELECT column_name FROM information_schema.columns
 		WHERE table_schema = $1 AND table_name = $2 AND column_name = $3
-	]], string.trim(schema_name), string.trim(table_name), string.trim(column_name))
+	]], schema_name:trim(), table_name:trim(), column_name:trim()) ~= nil
-	return result ~= nil
 end
 
 function Connection:create_table(table_name, schema)
-	if string.is_blank(table_name) or string.is_blank(schema) then
+	if table_name:is_blank() or schema:is_blank() then
 		error("Table name and schema cannot be empty")
 	end
-
+	return self:exec("CREATE TABLE IF NOT EXISTS {{table}} ({{schema}})":parse({
-	local query = string.template("CREATE TABLE IF NOT EXISTS ${table} (${schema})", {
 		table = table_name,
-		schema = string.trim(schema)
+		schema = schema:trim()
-	})
+	}))
-	return self:exec(query)
 end
 
 function Connection:drop_table(table_name, cascade)
-	if string.is_blank(table_name) then
+	if table_name:is_blank() then
 		error("Table name cannot be empty")
 	end
-
 	local cascade_clause = cascade and " CASCADE" or ""
-	local query = string.template("DROP TABLE IF EXISTS ${table}${cascade}", {
+	return self:exec("DROP TABLE IF EXISTS {{table}}{{cascade}}":parse({
 		table = table_name,
 		cascade = cascade_clause
-	})
+	}))
-	return self:exec(query)
 end
 
 function Connection:add_column(table_name, column_def)
-	if string.is_blank(table_name) or string.is_blank(column_def) then
+	if table_name:is_blank() or column_def:is_blank() then
 		error("Table name and column definition cannot be empty")
 	end
-
+	return self:exec("ALTER TABLE {{table}} ADD COLUMN IF NOT EXISTS {{column}}":parse({
-	local query = string.template("ALTER TABLE ${table} ADD COLUMN IF NOT EXISTS ${column}", {
 		table = table_name,
-		column = string.trim(column_def)
+		column = column_def:trim()
-	})
+	}))
-	return self:exec(query)
 end
 
 function Connection:drop_column(table_name, column_name, cascade)
-	if string.is_blank(table_name) or string.is_blank(column_name) then
+	if table_name:is_blank() or column_name:is_blank() then
 		error("Table name and column name cannot be empty")
 	end
-
 	local cascade_clause = cascade and " CASCADE" or ""
-	local query = string.template("ALTER TABLE ${table} DROP COLUMN IF EXISTS ${column}${cascade}", {
+	return self:exec("ALTER TABLE {{table}} DROP COLUMN IF EXISTS {{column}}{{cascade}}":parse({
 		table = table_name,
 		column = column_name,
 		cascade = cascade_clause
-	})
+	}))
-	return self:exec(query)
 end
 
 function Connection:create_index(index_name, table_name, columns, unique, method)
-	if string.is_blank(index_name) or string.is_blank(table_name) then
+	if index_name:is_blank() or table_name:is_blank() then
 		error("Index name and table name cannot be empty")
 	end
 
 	local unique_clause = unique and "UNIQUE " or ""
-	local method_clause = method and string.template(" USING ${method}", {method = string.upper(method)}) or ""
+	local method_clause = method and " USING " .. method:upper() or ""
 	local columns_str = type(columns) == "table" and table.concat(columns, ", ") or tostring(columns)
 
-	local query = string.template("CREATE ${unique}INDEX IF NOT EXISTS ${index} ON ${table}${method} (${columns})", {
+	return self:exec("CREATE {{unique}}INDEX IF NOT EXISTS {{index}} ON {{table}}{{method}} ({{columns}})":parse({
 		unique = unique_clause,
 		index = index_name,
 		table = table_name,
 		method = method_clause,
 		columns = columns_str
-	})
+	}))
-	return self:exec(query)
 end
 
 function Connection:drop_index(index_name, cascade)
-	if string.is_blank(index_name) then
+	if index_name:is_blank() then
 		error("Index name cannot be empty")
 	end
-
 	local cascade_clause = cascade and " CASCADE" or ""
-	local query = string.template("DROP INDEX IF EXISTS ${index}${cascade}", {
+	return self:exec("DROP INDEX IF EXISTS {{index}}{{cascade}}":parse({
 		index = index_name,
 		cascade = cascade_clause
-	})
+	}))
-	return self:exec(query)
 end
 
 -- PostgreSQL-specific functions
 function Connection:vacuum(table_name, analyze)
 	local analyze_clause = analyze and " ANALYZE" or ""
-	local table_clause = table_name and string.template(" ${table}", {table = table_name}) or ""
+	local table_clause = table_name and " " .. table_name or ""
-	return self:exec(string.template("VACUUM${analyze}${table}", {
+	return self:exec("VACUUM{{analyze}}{{table}}":parse({
 		analyze = analyze_clause,
 		table = table_clause
 	}))
 end
 
 function Connection:analyze(table_name)
-	local table_clause = table_name and string.template(" ${table}", {table = table_name}) or ""
+	local table_clause = table_name and " " .. table_name or ""
-	return self:exec(string.template("ANALYZE${table}", {table = table_clause}))
+	return self:exec("ANALYZE{{table}}":parse({table = table_clause}))
 end
 
 function Connection:reindex(name, type)
-	if string.is_blank(name) then
+	if name:is_blank() then
 		error("Name cannot be empty for REINDEX")
 	end
 
-	type = type or "INDEX"
+	type = (type or "INDEX"):upper()
 	local valid_types = {"INDEX", "TABLE", "SCHEMA", "DATABASE", "SYSTEM"}
-	local type_upper = string.upper(type)
 
-	if not table.contains(valid_types, type_upper) then
+	if not table.contains(valid_types, type) then
-		error(string.template("Invalid REINDEX type: ${type}", {type = type}))
+		error("Invalid REINDEX type: " .. type)
 	end
 
-	return self:exec(string.template("REINDEX ${type} ${name}", {
+	return self:exec("REINDEX {{type}} {{name}}":parse({type = type, name = name}))
-		type = type_upper,
-		name = name
-	}))
 end
 
--- PostgreSQL settings and introspection
 function Connection:show(setting)
-	if string.is_blank(setting) then
+	if setting:is_blank() then
 		error("Setting name cannot be empty")
 	end
-	return self:query_value(string.template("SHOW ${setting}", {setting = setting}))
+	return self:query_value("SHOW {{setting}}":parse({setting = setting}))
 end
 
 function Connection:set(setting, value)
-	if string.is_blank(setting) then
+	if setting:is_blank() then
 		error("Setting name cannot be empty")
 	end
-	return self:exec(string.template("SET ${setting} = ${value}", {
+	return self:exec("SET {{setting}} = {{value}}":parse({
 		setting = setting,
 		value = tostring(value)
 	}))
@@ -505,12 +426,11 @@ end
 
 function Connection:list_tables(schema_name)
 	schema_name = schema_name or "public"
-	return self:query("SELECT tablename FROM pg_tables WHERE schemaname = $1 ORDER BY tablename",
+	return self:query("SELECT tablename FROM pg_tables WHERE schemaname = $1 ORDER BY tablename", schema_name:trim())
-		string.trim(schema_name))
 end
 
 function Connection:describe_table(table_name, schema_name)
-	if string.is_blank(table_name) then
+	if table_name:is_blank() then
 		error("Table name cannot be empty")
 	end
 
@@ -520,64 +440,64 @@ function Connection:describe_table(table_name, schema_name)
 		FROM information_schema.columns
 		WHERE table_schema = $1 AND table_name = $2
 		ORDER BY ordinal_position
-	]], string.trim(schema_name), string.trim(table_name))
+	]], schema_name:trim(), table_name:trim())
 end
 
 -- JSON/JSONB helpers
 function Connection:json_extract(column, path)
-	if string.is_blank(column) or string.is_blank(path) then
+	if column:is_blank() or path:is_blank() then
 		error("Column and path cannot be empty")
 	end
-	return string.template("${column}->'${path}'", {column = column, path = path})
+	return "{{column}}->'{{path}}'":parse({column = column, path = path})
 end
 
 function Connection:json_extract_text(column, path)
-	if string.is_blank(column) or string.is_blank(path) then
+	if column:is_blank() or path:is_blank() then
 		error("Column and path cannot be empty")
 	end
-	return string.template("${column}->>'${path}'", {column = column, path = path})
+	return "{{column}}->>'{{path}}'":parse({column = column, path = path})
 end
 
 function Connection:jsonb_contains(column, value)
-	if string.is_blank(column) or string.is_blank(value) then
+	if column:is_blank() or value:is_blank() then
 		error("Column and value cannot be empty")
 	end
-	return string.template("${column} @> '${value}'", {column = column, value = value})
+	return "{{column}} @> '{{value}}'":parse({column = column, value = value})
 end
 
 function Connection:jsonb_contained_by(column, value)
-	if string.is_blank(column) or string.is_blank(value) then
+	if column:is_blank() or value:is_blank() then
 		error("Column and value cannot be empty")
 	end
-	return string.template("${column} <@ '${value}'", {column = column, value = value})
+	return "{{column}} <@ '{{value}}'":parse({column = column, value = value})
 end
 
 -- Array helpers
 function Connection:array_contains(column, value)
-	if string.is_blank(column) then
+	if column:is_blank() then
 		error("Column cannot be empty")
 	end
-	return string.template("$1 = ANY(${column})", {column = column})
+	return "$1 = ANY({{column}})":parse({column = column})
 end
 
 function Connection:array_length(column)
-	if string.is_blank(column) then
+	if column:is_blank() then
 		error("Column cannot be empty")
 	end
-	return string.template("array_length(${column}, 1)", {column = column})
+	return "array_length({{column}}, 1)":parse({column = column})
 end
 
 -- Connection management
 function postgres.parse_dsn(dsn)
-	if string.is_blank(dsn) then
+	if dsn:is_blank() then
 		return nil, "DSN cannot be empty"
 	end
 
 	local parts = {}
-	for pair in string.trim(dsn):gmatch("[^%s]+") do
+	for pair in dsn:trim():gmatch("[^%s]+") do
 		local key, value = pair:match("([^=]+)=(.+)")
 		if key and value then
-			parts[string.trim(key)] = string.trim(value)
+			parts[key:trim()] = value:trim()
 		end
 	end
 
@@ -585,15 +505,13 @@ function postgres.parse_dsn(dsn)
 end
 
 function postgres.connect(dsn)
-	if string.is_blank(dsn) then
+	if dsn:is_blank() then
 		error("DSN cannot be empty")
 	end
 
-	local conn_id = moonshark.sql_connect("postgres", string.trim(dsn))
+	local conn_id = moonshark.sql_connect("postgres", dsn:trim())
 	if conn_id then
-		local conn = {_id = conn_id}
+		return setmetatable({_id = conn_id}, Connection)
-		setmetatable(conn, Connection)
-		return conn
 	end
 	return nil
 end
@@ -625,10 +543,7 @@ end
 
 function postgres.query_row(dsn, query_str, ...)
 	local results = postgres.query(dsn, query_str, ...)
-	if results and #results > 0 then
+	return results and #results > 0 and results[1] or nil
-		return results[1]
-	end
-	return nil
 end
 
 function postgres.query_value(dsn, query_str, ...)
@@ -649,8 +564,7 @@ function postgres.migrate(dsn, migrations, schema)
 		error("Failed to connect to PostgreSQL database for migration")
 	end
 
-	conn:create_table("_migrations",
+	conn:create_table("_migrations", "id SERIAL PRIMARY KEY, name TEXT UNIQUE NOT NULL, applied_at TIMESTAMPTZ DEFAULT NOW()")
-		"id SERIAL PRIMARY KEY, name TEXT UNIQUE NOT NULL, applied_at TIMESTAMPTZ DEFAULT NOW()")
 
 	local tx = conn:begin()
 	if not tx then
@@ -658,18 +572,14 @@ function postgres.migrate(dsn, migrations, schema)
 		error("Failed to begin migration transaction")
 	end
 
-	local success = true
-	local error_msg = ""
-
 	for _, migration in ipairs(migrations) do
-		if not migration.name or string.is_blank(migration.name) then
+		if not migration.name or migration.name:is_blank() then
-			error_msg = "Migration must have a non-empty name"
+			tx:rollback()
-			success = false
+			conn:close()
-			break
+			error("Migration must have a non-empty name")
 		end
 
-		local existing = conn:query_value("SELECT id FROM _migrations WHERE name = $1",
+		local existing = conn:query_value("SELECT id FROM _migrations WHERE name = $1", migration.name:trim())
-			string.trim(migration.name))
 		if not existing then
 			local ok, err = pcall(function()
 				if type(migration.up) == "string" then
@@ -682,52 +592,34 @@ function postgres.migrate(dsn, migrations, schema)
 			end)
 
 			if ok then
-				conn:exec("INSERT INTO _migrations (name) VALUES ($1)", string.trim(migration.name))
+				conn:exec("INSERT INTO _migrations (name) VALUES ($1)", migration.name:trim())
-				print(string.template("Applied migration: ${name}", {name = migration.name}))
+				print("Applied migration: {{name}}":parse({name = migration.name}))
-			else
-				success = false
-				error_msg = string.template("Migration '${name}' failed: ${error}", {
-					name = migration.name,
-					error = err or "unknown error"
-				})
-				break
-			end
-		end
-	end
-
-	if success then
-		tx:commit()
 			else
 				tx:rollback()
 				conn:close()
-		error(error_msg)
+				error("Migration '{{name}}' failed: {{error}}":parse({
+					name = migration.name,
+					error = err or "unknown error"
+				}))
+			end
+		end
 	end
 
+	tx:commit()
 	conn:close()
 	return true
 end
 
--- Simplified result processing utilities
+-- Result processing utilities
 function postgres.to_array(results, column_name)
-	if not results or table.is_empty(results) then
+	if not results or table.is_empty(results) then return {} end
-		return {}
+	if column_name:is_blank() then error("Column name cannot be empty") end
-	end
-
-	if string.is_blank(column_name) then
-		error("Column name cannot be empty")
-	end
-
 	return table.map(results, function(row) return row[column_name] end)
 end
 
 function postgres.to_map(results, key_column, value_column)
-	if not results or table.is_empty(results) then
+	if not results or table.is_empty(results) then return {} end
-		return {}
+	if key_column:is_blank() then error("Key column name cannot be empty") end
-	end
-
-	if string.is_blank(key_column) then
-		error("Key column name cannot be empty")
-	end
 
 	local map = {}
 	for _, row in ipairs(results) do
@@ -738,18 +630,11 @@ function postgres.to_map(results, key_column, value_column)
 end
 
 function postgres.group_by(results, column_name)
-	if not results or table.is_empty(results) then
+	if not results or table.is_empty(results) then return {} end
-		return {}
+	if column_name:is_blank() then error("Column name cannot be empty") end
-	end
-
-	if string.is_blank(column_name) then
-		error("Column name cannot be empty")
-	end
-
 	return table.group_by(results, function(row) return row[column_name] end)
 end
 
--- Simplified debug helper
 function postgres.print_results(results)
 	if not results or table.is_empty(results) then
 		print("No results")
@@ -762,18 +647,15 @@ function postgres.print_results(results)
 	-- Calculate column widths
 	local widths = {}
 	for _, col in ipairs(columns) do
-		widths[col] = string.length(col)
+		widths[col] = col:length()
-	end
-
 		for _, row in ipairs(results) do
-		for _, col in ipairs(columns) do
 			local value = tostring(row[col] or "")
-			widths[col] = math.max(widths[col], string.length(value))
+			widths[col] = math.max(widths[col], value:length())
 		end
 	end
 
-	-- Print header
+	-- Print header and separator
-	local header_parts = table.map(columns, function(col) return string.pad_right(col, widths[col]) end)
+	local header_parts = table.map(columns, function(col) return col:pad_right(widths[col]) end)
 	local separator_parts = table.map(columns, function(col) return string.repeat_("-", widths[col]) end)
 
 	print(table.concat(header_parts, " | "))
@@ -783,22 +665,22 @@ function postgres.print_results(results)
 	for _, row in ipairs(results) do
 		local value_parts = table.map(columns, function(col)
 			local value = tostring(row[col] or "")
-			return string.pad_right(value, widths[col])
+			return value:pad_right(widths[col])
 		end)
 		print(table.concat(value_parts, " | "))
 	end
 end
 
 function postgres.escape_identifier(name)
-	if string.is_blank(name) then
+	if name:is_blank() then
 		error("Identifier name cannot be empty")
 	end
-	return string.template('"${name}"', {name = string.replace(name, '"', '""')})
+	return '"{{name}}"':parse({name = name:replace('"', '""')})
 end
 
 function postgres.escape_literal(value)
 	if type(value) == "string" then
-		return string.template("'${value}'", {value = string.replace(value, "'", "''")})
+		return "'{{value}}'":parse({value = value:replace("'", "''")})
 	end
 	return tostring(value)
 end

modules/sqlite/sqlite.lua

@@ -23,24 +23,19 @@ function Connection:query(query_str, ...)
 	if not self._id then
 		error("Connection is closed")
 	end
-	query_str = string.normalize_whitespace(query_str)
+	return moonshark.sql_query(self._id, query_str:normalize_whitespace(), ...)
-	return moonshark.sql_query(self._id, query_str, ...)
 end
 
 function Connection:exec(query_str, ...)
 	if not self._id then
 		error("Connection is closed")
 	end
-	query_str = string.normalize_whitespace(query_str)
+	return moonshark.sql_exec(self._id, query_str:normalize_whitespace(), ...)
-	return moonshark.sql_exec(self._id, query_str, ...)
 end
 
 function Connection:query_row(query_str, ...)
 	local results = self:query(query_str, ...)
-	if results and #results > 0 then
+	return results and #results > 0 and results[1] or nil
-		return results[1]
-	end
-	return nil
 end
 
 function Connection:query_value(query_str, ...)
@@ -53,57 +48,40 @@ function Connection:query_value(query_str, ...)
 	return nil
 end
 
--- Enhanced transaction support
 function Connection:begin()
 	local result = self:exec("BEGIN")
 	if result then
 		return {
 			conn = self,
 			active = true,
-
 			commit = function(tx)
 				if tx.active then
-					local result = tx.conn:exec("COMMIT")
 					tx.active = false
-					return result
+					return tx.conn:exec("COMMIT")
 				end
 				return false
 			end,
-
 			rollback = function(tx)
 				if tx.active then
-					local result = tx.conn:exec("ROLLBACK")
 					tx.active = false
-					return result
+					return tx.conn:exec("ROLLBACK")
 				end
 				return false
 			end,
-
 			query = function(tx, query_str, ...)
-				if not tx.active then
+				if not tx.active then error("Transaction is not active") end
-					error("Transaction is not active")
-				end
 				return tx.conn:query(query_str, ...)
 			end,
-
 			exec = function(tx, query_str, ...)
-				if not tx.active then
+				if not tx.active then error("Transaction is not active") end
-					error("Transaction is not active")
-				end
 				return tx.conn:exec(query_str, ...)
 			end,
-
 			query_row = function(tx, query_str, ...)
-				if not tx.active then
+				if not tx.active then error("Transaction is not active") end
-					error("Transaction is not active")
-				end
 				return tx.conn:query_row(query_str, ...)
 			end,
-
 			query_value = function(tx, query_str, ...)
-				if not tx.active then
+				if not tx.active then error("Transaction is not active") end
-					error("Transaction is not active")
-				end
 				return tx.conn:query_value(query_str, ...)
 			end
 		}
@@ -111,93 +89,85 @@ function Connection:begin()
 	return nil
 end
 
--- Simplified query builders using table utilities
 function Connection:insert(table_name, data)
-	if string.is_blank(table_name) then
+	if table_name:is_blank() then
 		error("Table name cannot be empty")
 	end
 
 	local keys = table.keys(data)
 	local values = table.values(data)
-	local placeholders = table.map(keys, function() return "?" end)
+	local placeholders = string.repeat_("?, ", #keys):trim_right(", ")
 
-	local query = string.template("INSERT INTO ${table} (${columns}) VALUES (${placeholders})", {
+	local query = "INSERT INTO {{table}} ({{columns}}) VALUES ({{placeholders}})":parse({
 		table = table_name,
-		columns = table.concat(keys, ", "),
+		columns = keys:join(", "),
-		placeholders = table.concat(placeholders, ", ")
+		placeholders = placeholders
 	})
 
 	return self:exec(query, unpack(values))
 end
 
 function Connection:upsert(table_name, data, conflict_columns)
-	if string.is_blank(table_name) then
+	if table_name:is_blank() then
 		error("Table name cannot be empty")
 	end
 
 	local keys = table.keys(data)
 	local values = table.values(data)
-	local placeholders = table.map(keys, function() return "?" end)
+	local placeholders = string.repeat_("?, ", #keys):trim_right(", ")
-	local updates = table.map(keys, function(key)
+	local updates = table.map(keys, function(key) return key .. " = excluded." .. key end):join(", ")
-		return string.template("${key} = excluded.${key}", {key = key})
-	end)
 
 	local conflict_clause = ""
 	if conflict_columns then
 		if type(conflict_columns) == "string" then
-			conflict_clause = string.template("(${columns})", {columns = conflict_columns})
+			conflict_clause = "(" .. conflict_columns .. ")"
 		else
-			conflict_clause = string.template("(${columns})", {columns = table.concat(conflict_columns, ", ")})
+			conflict_clause = "(" .. table.concat(conflict_columns, ", ") .. ")"
 		end
 	end
 
-	local query = string.template("INSERT INTO ${table} (${columns}) VALUES (${placeholders}) ON CONFLICT ${conflict} DO UPDATE SET ${updates}", {
+	local query = "INSERT INTO {{table}} ({{columns}}) VALUES ({{placeholders}}) ON CONFLICT {{conflict}} DO UPDATE SET {{updates}}":parse({
 		table = table_name,
-		columns = table.concat(keys, ", "),
+		columns = keys:join(", "),
-		placeholders = table.concat(placeholders, ", "),
+		placeholders = placeholders,
 		conflict = conflict_clause,
-		updates = table.concat(updates, ", ")
+		updates = updates
 	})
 
 	return self:exec(query, unpack(values))
 end
 
 function Connection:update(table_name, data, where_clause, ...)
-	if string.is_blank(table_name) then
+	if table_name:is_blank() then
 		error("Table name cannot be empty")
 	end
-	if string.is_blank(where_clause) then
+	if where_clause:is_blank() then
 		error("WHERE clause cannot be empty for UPDATE")
 	end
 
 	local keys = table.keys(data)
 	local values = table.values(data)
-	local sets = table.map(keys, function(key)
+	local sets = table.map(keys, function(key) return key .. " = ?" end):join(", ")
-		return string.template("${key} = ?", {key = key})
-	end)
 
-	local query = string.template("UPDATE ${table} SET ${sets} WHERE ${where}", {
+	local query = "UPDATE {{table}} SET {{sets}} WHERE {{where}}":parse({
 		table = table_name,
-		sets = table.concat(sets, ", "),
+		sets = sets,
 		where = where_clause
 	})
 
-	-- Add WHERE clause parameters
+	table.extend(values, {...})
-	local where_args = {...}
-	table.extend(values, where_args)
-
 	return self:exec(query, unpack(values))
 end
 
 function Connection:delete(table_name, where_clause, ...)
-	if string.is_blank(table_name) then
+	if table_name:is_blank() then
 		error("Table name cannot be empty")
 	end
-	if string.is_blank(where_clause) then
+	if where_clause:is_blank() then
 		error("WHERE clause cannot be empty for DELETE")
 	end
 
-	local query = string.template("DELETE FROM ${table} WHERE ${where}", {
+	local query = "DELETE FROM {{table}} WHERE {{where}}":parse({
 		table = table_name,
 		where = where_clause
 	})
@@ -205,7 +175,7 @@ function Connection:delete(table_name, where_clause, ...)
 end
 
 function Connection:select(table_name, columns, where_clause, ...)
-	if string.is_blank(table_name) then
+	if table_name:is_blank() then
 		error("Table name cannot be empty")
 	end
 
@@ -214,16 +184,15 @@ function Connection:select(table_name, columns, where_clause, ...)
 		columns = table.concat(columns, ", ")
 	end
 
-	local query
+	if where_clause and not where_clause:is_blank() then
-	if where_clause and not string.is_blank(where_clause) then
+		local query = "SELECT {{columns}} FROM {{table}} WHERE {{where}}":parse({
-		query = string.template("SELECT ${columns} FROM ${table} WHERE ${where}", {
 			columns = columns,
 			table = table_name,
 			where = where_clause
 		})
 		return self:query(query, ...)
 	else
-		query = string.template("SELECT ${columns} FROM ${table}", {
+		local query = "SELECT {{columns}} FROM {{table}}":parse({
 			columns = columns,
 			table = table_name
 		})
@@ -231,75 +200,63 @@ function Connection:select(table_name, columns, where_clause, ...)
 	end
 end
 
--- Schema helpers
 function Connection:table_exists(table_name)
-	if string.is_blank(table_name) then
+	if table_name:is_blank() then return false end
-		return false
+	return self:query_value("SELECT name FROM sqlite_master WHERE type='table' AND name=?", table_name:trim()) ~= nil
-	end
-
-	local result = self:query_value(
-		"SELECT name FROM sqlite_master WHERE type='table' AND name=?",
-		string.trim(table_name)
-	)
-	return result ~= nil
 end
 
 function Connection:column_exists(table_name, column_name)
-	if string.is_blank(table_name) or string.is_blank(column_name) then
+	if table_name:is_blank() or column_name:is_blank() then return false end
-		return false
-	end
 
-	local result = self:query(string.template("PRAGMA table_info(${table})", {table = table_name}))
+	local result = self:query("PRAGMA table_info({{table}})":parse({table = table_name}))
 	if result then
 		return table.any(result, function(row)
-			return string.iequals(row.name, string.trim(column_name))
+			return row.name:iequals(column_name:trim())
 		end)
 	end
 	return false
 end
 
 function Connection:create_table(table_name, schema)
-	if string.is_blank(table_name) or string.is_blank(schema) then
+	if table_name:is_blank() or schema:is_blank() then
 		error("Table name and schema cannot be empty")
 	end
 
-	local query = string.template("CREATE TABLE IF NOT EXISTS ${table} (${schema})", {
+	local query = "CREATE TABLE IF NOT EXISTS {{table}} ({{schema}})":parse({
 		table = table_name,
-		schema = string.trim(schema)
+		schema = schema:trim()
 	})
 	return self:exec(query)
 end
 
 function Connection:drop_table(table_name)
-	if string.is_blank(table_name) then
+	if table_name:is_blank() then
 		error("Table name cannot be empty")
 	end
-
+	return self:exec("DROP TABLE IF EXISTS {{table}}":parse({table = table_name}))
-	local query = string.template("DROP TABLE IF EXISTS ${table}", {table = table_name})
-	return self:exec(query)
 end
 
 function Connection:add_column(table_name, column_def)
-	if string.is_blank(table_name) or string.is_blank(column_def) then
+	if table_name:is_blank() or column_def:is_blank() then
 		error("Table name and column definition cannot be empty")
 	end
 
-	local query = string.template("ALTER TABLE ${table} ADD COLUMN ${column}", {
+	local query = "ALTER TABLE {{table}} ADD COLUMN {{column}}":parse({
 		table = table_name,
-		column = string.trim(column_def)
+		column = column_def:trim()
 	})
 	return self:exec(query)
 end
 
 function Connection:create_index(index_name, table_name, columns, unique)
-	if string.is_blank(index_name) or string.is_blank(table_name) then
+	if index_name:is_blank() or table_name:is_blank() then
 		error("Index name and table name cannot be empty")
 	end
 
 	local unique_clause = unique and "UNIQUE " or ""
 	local columns_str = type(columns) == "table" and table.concat(columns, ", ") or tostring(columns)
 
-	local query = string.template("CREATE ${unique}INDEX IF NOT EXISTS ${index} ON ${table} (${columns})", {
+	local query = "CREATE {{unique}}INDEX IF NOT EXISTS {{index}} ON {{table}} ({{columns}})":parse({
 		unique = unique_clause,
 		index = index_name,
 		table = table_name,
@@ -309,12 +266,10 @@ function Connection:create_index(index_name, table_name, columns, unique)
 end
 
 function Connection:drop_index(index_name)
-	if string.is_blank(index_name) then
+	if index_name:is_blank() then
 		error("Index name cannot be empty")
 	end
-
+	return self:exec("DROP INDEX IF EXISTS {{index}}":parse({index = index_name}))
-	local query = string.template("DROP INDEX IF EXISTS ${index}", {index = index_name})
-	return self:exec(query)
 end
 
 -- SQLite-specific functions
@@ -332,29 +287,29 @@ end
 
 function Connection:foreign_keys(enabled)
 	local value = enabled and "ON" or "OFF"
-	return self:exec(string.template("PRAGMA foreign_keys = ${value}", {value = value}))
+	return self:exec("PRAGMA foreign_keys = {{value}}":parse({value = value}))
 end
 
 function Connection:journal_mode(mode)
-	mode = mode or "WAL"
+	mode = (mode or "WAL"):upper()
 	local valid_modes = {"DELETE", "TRUNCATE", "PERSIST", "MEMORY", "WAL", "OFF"}
 
-	if not table.contains(table.map(valid_modes, string.upper), string.upper(mode)) then
+	if not table.contains(valid_modes, mode) then
 		error("Invalid journal mode: " .. mode)
 	end
 
-	return self:query(string.template("PRAGMA journal_mode = ${mode}", {mode = string.upper(mode)}))
+	return self:query("PRAGMA journal_mode = {{mode}}":parse({mode = mode}))
 end
 
 function Connection:synchronous(level)
-	level = level or "NORMAL"
+	level = (level or "NORMAL"):upper()
 	local valid_levels = {"OFF", "NORMAL", "FULL", "EXTRA"}
 
-	if not table.contains(valid_levels, string.upper(level)) then
+	if not table.contains(valid_levels, level) then
 		error("Invalid synchronous level: " .. level)
 	end
 
-	return self:exec(string.template("PRAGMA synchronous = ${level}", {level = string.upper(level)}))
+	return self:exec("PRAGMA synchronous = {{level}}":parse({level = level}))
 end
 
 function Connection:cache_size(size)
@@ -362,35 +317,30 @@ function Connection:cache_size(size)
 	if type(size) ~= "number" then
 		error("Cache size must be a number")
 	end
-	return self:exec(string.template("PRAGMA cache_size = ${size}", {size = tostring(size)}))
+	return self:exec("PRAGMA cache_size = {{size}}":parse({size = tostring(size)}))
 end
 
 function Connection:temp_store(mode)
-	mode = mode or "MEMORY"
+	mode = (mode or "MEMORY"):upper()
 	local valid_modes = {"DEFAULT", "FILE", "MEMORY"}
 
-	if not table.contains(valid_modes, string.upper(mode)) then
+	if not table.contains(valid_modes, mode) then
 		error("Invalid temp_store mode: " .. mode)
 	end
 
-	return self:exec(string.template("PRAGMA temp_store = ${mode}", {mode = string.upper(mode)}))
+	return self:exec("PRAGMA temp_store = {{mode}}":parse({mode = mode}))
 end
 
 -- Connection management
 function sqlite.open(database_path)
 	database_path = database_path or ":memory:"
-
+	if database_path ~= ":memory:" and database_path:is_blank() then
-	if database_path ~= ":memory:" then
-		if string.is_blank(database_path) then
 		database_path = ":memory:"
 	end
-	end
 
 	local conn_id = moonshark.sql_connect("sqlite", database_path:trim())
 	if conn_id then
-		local conn = {_id = conn_id}
+		return setmetatable({_id = conn_id}, Connection)
-		setmetatable(conn, Connection)
-		return conn
 	end
 	return nil
 end
@@ -401,9 +351,7 @@ sqlite.connect = sqlite.open
 function sqlite.query(database_path, query_str, ...)
 	local conn = sqlite.open(database_path)
 	if not conn then
-		error(string.template("Failed to open SQLite database: ${path}", {
+		error("Failed to open SQLite database: {{path}}":parse({path = database_path or ":memory:"}))
-			path = database_path or ":memory:"
-		}))
 	end
 
 	local results = conn:query(query_str, ...)
@@ -414,9 +362,7 @@ end
 function sqlite.exec(database_path, query_str, ...)
 	local conn = sqlite.open(database_path)
 	if not conn then
-		error(string.template("Failed to open SQLite database: ${path}", {
+		error("Failed to open SQLite database: {{path}}":parse({path = database_path or ":memory:"}))
-			path = database_path or ":memory:"
-		}))
 	end
 
 	local result = conn:exec(query_str, ...)
@@ -426,10 +372,7 @@ end
 
 function sqlite.query_row(database_path, query_str, ...)
 	local results = sqlite.query(database_path, query_str, ...)
-	if results and #results > 0 then
+	return results and #results > 0 and results[1] or nil
-		return results[1]
-	end
-	return nil
 end
 
 function sqlite.query_value(database_path, query_str, ...)
@@ -449,8 +392,7 @@ function sqlite.migrate(database_path, migrations)
 		error("Failed to open SQLite database for migration")
 	end
 
-	conn:create_table("_migrations",
+	conn:create_table("_migrations", "id INTEGER PRIMARY KEY, name TEXT UNIQUE, applied_at DATETIME DEFAULT CURRENT_TIMESTAMP")
-		"id INTEGER PRIMARY KEY, name TEXT UNIQUE, applied_at DATETIME DEFAULT CURRENT_TIMESTAMP")
 
 	local tx = conn:begin()
 	if not tx then
@@ -458,18 +400,14 @@ function sqlite.migrate(database_path, migrations)
 		error("Failed to begin migration transaction")
 	end
 
-	local success = true
-	local error_msg = ""
-
 	for _, migration in ipairs(migrations) do
-		if not migration.name or string.is_blank(migration.name) then
+		if not migration.name or migration.name:is_blank() then
-			error_msg = "Migration must have a non-empty name"
+			tx:rollback()
-			success = false
+			conn:close()
-			break
+			error("Migration must have a non-empty name")
 		end
 
-		local existing = conn:query_value("SELECT id FROM _migrations WHERE name = ?",
+		local existing = conn:query_value("SELECT id FROM _migrations WHERE name = ?", migration.name:trim())
-			string.trim(migration.name))
 		if not existing then
 			local ok, err = pcall(function()
 				if type(migration.up) == "string" then
@@ -482,52 +420,34 @@ function sqlite.migrate(database_path, migrations)
 			end)
 
 			if ok then
-				conn:exec("INSERT INTO _migrations (name) VALUES (?)", string.trim(migration.name))
+				conn:exec("INSERT INTO _migrations (name) VALUES (?)", migration.name:trim())
-				print(string.template("Applied migration: ${name}", {name = migration.name}))
+				print("Applied migration: {{name}}":parse({name = migration.name}))
-			else
-				success = false
-				error_msg = string.template("Migration '${name}' failed: ${error}", {
-					name = migration.name,
-					error = err or "unknown error"
-				})
-				break
-			end
-		end
-	end
-
-	if success then
-		tx:commit()
 			else
 				tx:rollback()
 				conn:close()
-		error(error_msg)
+				error("Migration '{{name}}' failed: {{error}}":parse({
+					name = migration.name,
+					error = err or "unknown error"
+				}))
+			end
+		end
 	end
 
+	tx:commit()
 	conn:close()
 	return true
 end
 
--- Simplified result processing using table utilities
+-- Result processing utilities
 function sqlite.to_array(results, column_name)
-	if not results or table.is_empty(results) then
+	if not results or table.is_empty(results) then return {} end
-		return {}
+	if column_name:is_blank() then error("Column name cannot be empty") end
-	end
-
-	if string.is_blank(column_name) then
-		error("Column name cannot be empty")
-	end
-
 	return table.map(results, function(row) return row[column_name] end)
 end
 
 function sqlite.to_map(results, key_column, value_column)
-	if not results or table.is_empty(results) then
+	if not results or table.is_empty(results) then return {} end
-		return {}
+	if key_column:is_blank() then error("Key column name cannot be empty") end
-	end
-
-	if string.is_blank(key_column) then
-		error("Key column name cannot be empty")
-	end
 
 	local map = {}
 	for _, row in ipairs(results) do
@@ -538,18 +458,11 @@ function sqlite.to_map(results, key_column, value_column)
 end
 
 function sqlite.group_by(results, column_name)
-	if not results or table.is_empty(results) then
+	if not results or table.is_empty(results) then return {} end
-		return {}
+	if column_name:is_blank() then error("Column name cannot be empty") end
-	end
-
-	if string.is_blank(column_name) then
-		error("Column name cannot be empty")
-	end
-
 	return table.group_by(results, function(row) return row[column_name] end)
 end
 
--- Simplified debug helper
 function sqlite.print_results(results)
 	if not results or table.is_empty(results) then
 		print("No results")
@@ -560,17 +473,17 @@ function sqlite.print_results(results)
 	table.sort(columns)
 
 	-- Calculate column widths
-	local widths = table.map_values(table.to_map(columns, function(col) return col end, function(col) return string.length(col) end), function(width) return width end)
+	local widths = {}
-
-	for _, row in ipairs(results) do
 	for _, col in ipairs(columns) do
+		widths[col] = col:length()
+		for _, row in ipairs(results) do
 			local value = tostring(row[col] or "")
-			widths[col] = math.max(widths[col], string.length(value))
+			widths[col] = math.max(widths[col], value:length())
 		end
 	end
 
-	-- Print header
+	-- Print header and separator
-	local header_parts = table.map(columns, function(col) return string.pad_right(col, widths[col]) end)
+	local header_parts = table.map(columns, function(col) return col:pad_right(widths[col]) end)
 	local separator_parts = table.map(columns, function(col) return string.repeat_("-", widths[col]) end)
 
 	print(table.concat(header_parts, " | "))
@@ -580,7 +493,7 @@ function sqlite.print_results(results)
 	for _, row in ipairs(results) do
 		local value_parts = table.map(columns, function(col)
 			local value = tostring(row[col] or "")
-			return string.pad_right(value, widths[col])
+			return value:pad_right(widths[col])
 		end)
 		print(table.concat(value_parts, " | "))
 	end