Author name cluster

Curtis E. Dyreson

Possible papers associated with this exact author name in Arrow. This page groups case-insensitive exact name matches and is not a full identity disambiguation profile.

6 papers

2 author rows

TIME Conference 2025 Conference Paper

Temporal GraphQL: A Tree Grammar Approach

Curtis E. Dyreson
Bishal Sarkar

This paper presents a novel system, called Temporal GraphQL, for supporting temporal data in web services. A temporal web service is a service that provides a temporal view of data, that is, a view of the current data as well as past or future states of the data. Capturing the history of the data is important in data forensics, data auditing, and subscriptions, where an application continuously reads data. GraphQL is a technology for improving the development and management of web services. Originally developed by Facebook and widely used in industry, GraphQL is a query language for web services. This paper introduces Temporal GraphQL. We show how to use tree grammars to model GraphQL schemas, data, and queries, and propose temporal tree grammars to model Temporal GraphQL. We extend GraphQL with temporal snapshot, slice, and delta operators. To the best of our knowledge, this is the first work on Temporal GraphQL and temporal tree grammars.

Details

I&C Journal 2023 Journal Article

Achieving sequenced SQL with log-segmented timestamps

Curtis E. Dyreson
M.A. Manazir Ahsan

In a period-timestamped, relational temporal database, each tuple is timestamped with a period. The timestamp records when the tuple is “alive” in some temporal dimension. Sequenced semantics is a special semantics for evaluating a query in a temporal database. The semantics stipulates that the query must, in effect, be evaluated simultaneously in each time instant using the tuples alive at that instant. Previous research has proposed changes to a database management system's query evaluation engine to support sequenced semantics. We show how to achieve sequenced semantics without modifying a query evaluation engine. Our technique has two pillars. First we use log-segmented timestamps to record a tuple's lifetime. A log-segmented timestamp divides the time-line into segments of known length. Any temporal period can be represented by a small number of such segments. Second, by taking advantage of the properties of log-segmented timestamps, we translate a sequenced query to a non-temporal query, using the operations already present in an unmodified, non-temporal query evaluation engine. The paper provides translations for both relational algebra and SQL. We experimentally evaluate the SQL translation. The primary contribution of this paper is how to implement sequenced semantics using log-segmented timestamped tuples in a generic SQL DBMS.

Details DOI

TIME Conference 2023 Conference Paper

Optimization of Nonsequenced Queries Using Log-Segmented Timestamps

Curtis E. Dyreson

In a period-timestamped, relational temporal database, each tuple is timestamped with a period. The timestamp records when the tuple is "alive" in some temporal dimension. Nonsequenced semantics is a query evaluation semantics that involves adding temporal predicates and constructors to a query. We show how to use log-segmented timestamps to improve the efficiency of temporal, nonsequenced queries evaluated using a non-temporal DBMS, i. e. , a DBMS that has no special temporal indexes or query evaluation operators. A log-segmented timestamp divides the time-line into segments of known length. Any temporal period can be represented by a small number of such segments. The segments can be appended to a relation as additional columns. The advantage of log-segmented timestamps is that each segment can be indexed using standard database indexes, e. g. , a B^+-tree. A query optimizer can use the indexes to generate a lower cost query evaluation plan. This paper shows how to rewrite a query to use the additional columns and evaluates the time cost benefits and space cost disadvantages.

Details

TIME Conference 2021 Conference Paper

Achieving a Sequenced, Relational Query Language with Log-Segmented Timestamps

Curtis E. Dyreson
M. A. Manazir Ahsan

In a period-timestamped, relational temporal database, each tuple is timestamped with a period. The timestamp records when the tuple is "alive" in some temporal dimension. Sequenced semantics is a special semantics for evaluating a query in a temporal database. The semantics stipulates that the query must, in effect, be evaluated simultaneously in each time instant using the tuples alive at that instant. Previous research has proposed changes to the query evaluation engine to support sequenced semantics. In this paper we show how to achieve sequenced semantics without modifying a query evaluation engine. Our technique has two pillars. First we use log-segmented timestamps to record a tuple’s lifetime. A log-segmented timestamp divides the time-line into segments of known length. Any temporal period can be represented by a small number of such segments. Second, by taking advantage of the properties of log-segmented timestamps, we translate a sequenced relational algebra query to a non-temporal relational algebra query, using the operations already present in an unmodified, non-temporal query evaluation engine. The primary contribution of this paper is how to implement sequenced semantics using log-segmented timestamped tuples in a generic DBMS, which, to the best of our knowledge, has not been previously shown.

Details

TIME Conference 2016 Conference Paper

Translating Temporal SQL to Nested SQL

Curtis E. Dyreson
Venkata A. Rani

This paper presents a technique for weaving temporal semantics into an SQL query. We assume that a query writer programs a query and then annotates the query with some temporal semantics, such as sequenced or nonsequenced semantics. The annotation is a lightweight temporal statement modifier, it changes the semantics by which the query is evaluated. Annotations can be specified for a wide variety of semantics including sequenced and nonsequenced semantics. We give a denotational semantics for translating SQL queries with temporal annotations into Nested SQL. Nested SQL is SQL with some additional operations. We also describe how the translation is implemented using an ANTLR grammar for SQLite.

Details

TIME Conference 2015 Conference Paper

Unifying Sequenced and Non-sequenced Semantics

Curtis E. Dyreson
Venkata A. Rani
Amani M. Shatnawi

Sequenced and nonsequenced semantics were introduced as different semantics for the evaluation of an operation in a temporal database such as a query or data modification. In this paper we present a new framework that shows both semantics are variants of a general temporal semantics. Our framework uses tuple lineage to track tuples through operations. We present the general semantics and show additional semantics that can be realized. We also show how the semantics can be woven into an operation using annotations.

Details