These topics cover what PSQL is and what it can do for you:

PSQL is a comprehensive database management system built around the MicroKernel Engine.

This section explains the product and its components.

Loosely defined, a database is simply a collection of data. Generally, the data is structured by dividing it into sub-sets of information that share the same characteristics. Some examples of a database are:

In the particular context of this product, a database is a specific, well-defined collection of related information. You can probably find one or more databases available on your computer or your network. For example, you may have a database of information related to vendors from whom you purchase supplies or raw materials, and you probably also have a database containing customer or member information. Each of these is a distinct, well-defined collection of related information.

As citizens of the computer age, we are surrounded by collections of information – databases –everywhere we go. Unfortunately, all this data is of no use to anyone without methods to sort it, search it, analyze it, and keep it current.

A database management system, or DBMS, is a computer program designed to manage large amounts of data and to allow other computer programs and people to interact with the data. A DBMS can also be referred to informally as a database engine or simply an engine. A DBMS performs the following tasks:

In summary, the DBMS organizes your data, keeps it safe, and helps you to use it and understand it.

The PSQL DBMS consists of a variety of components for to help you manage data:

The PSQL MicroKernel Engine is the high-performance heart of PSQL. This engine works directly with the data files on your computer’s hard disk. When requested, it directly inserts new data, deletes unnecessary data, and ensures the safety and integrity of the data files at all times, even when people and applications are working with the data.

The PSQL Relational Engine interacts with the MicroKernel Engine and the PSQL Client. This engine provides many important features, including support for Microsoft ODBC, sophisticated search and analysis capability, and security.

In client-server systems, the PSQL Client resides on the computer that makes requests to a PSQL Server. The client interacts with the client application and across the network with both the MicroKernel Engine and the Relational Engine on the server.

The PSQL Control Center (PCC) is a graphical tool that helps you create and manipulate databases and manage your DBMS. It allows you to access nearly product functions from one place. For a tour of PCC, see Using PSQL Control Center.

The PSQL database engines come with a variety of graphical and command-line tools to support the testing, configuring, and manipulating of the many features and options provided by PSQL. All of the utilities run on Windows, and most support remote access to Linux and macOS database server engines.

PSQL comes with a complete set of online documentation. For more information about the documentation, see Using PSQL Documentation.

The topics in this section cover basic database concepts and the features that distinguish PSQL from other database products.

Most database management systems in use today share a common set of basic structures. The descriptions of these structures that follow are based on the following table:

The most basic element of a database is a value. A value is one piece of data, one characteristic, for a specific entity. For example, in the diagram, the name John Doe or the phone number 555-1212 is a value.

Another element is a column, or a field. A column represents a characteristic with no specific value. Columns generally have names that describe the given characteristic. For example, in the telephone book, Name and Phone are columns. They do not have specific values unless you look up a particular person. Field is sometimes used to refer to the generic characteristic of a specific row. For example, someone might point to a specific box in the table above and ask, “What is the value of that field?”

Another element is called a row, or a record. A row is a collection of all the values for one particular instance. For example, one entry in the phone book, complete with name, address, and phone number, is one record or row.

A cell is a column within a specific record. You can think of it as the intersection of a row and a column. Each cell has a specific value. For example, you might tell a coworker that the value of the cell located at row 2, column 3 is 12345.

A collection of rows and columns makes up a table. A table is a set of data that shares exactly the same structure. Tables generally have names that describe the contents of the table. For example, the table above is called Phone Book. With PSQL, each table is stored as a separate data file on the hard disk.

An index is an ordered list of all the values in a particular column. A table can have zero or more indexes on it. The database engine uses indexes to find specific records in the database without having to step through every record one at a time. Creating indexes on columns which will frequently be used in database searches is likely to improve the performance of your database.

A database is a collection of one or more tables. The data in the tables does not need to be related among the various tables, but usually there are many relations. For example, a database might consist of the Food Preferences table below, and the Phone Book table above. With PSQL, a database consists of one or more data files and Data Dictionary Files (DDFs) on your hard disk. The DDFs are special data files that contain all the definitions for tables, columns, and other attributes that define the structure of your database.

The term schema refers to the complete set of definitions that describe the entire structure of a database. A typical schema defines tables, columns, indexes, and many other attributes. The DDFs for a database contain the database schema.

The term remote refers to an object, such as a file server or a database, that is not located on the computer you are using to access it. When you connect to a database over the network, you are connecting to a remote database. Remote is the opposite of local. Remote can refer to either the client or the server, depending on whether you are currently seated at the server computer or at one of its clients. Remote always refers to an object not located on the system you are using.

The term local refers to the computer you are using right now, or something stored on this computer. A local database is a database in which the data files are stored on the hard disk of the computer you are currently using. Local is the opposite of remote. Local can refer to either the client or the server, depending on whether you are currently seated at the server computer or a client computer.

The term relational refers to the storage of data in the form of related tables. The related tables allow relationships to be created between sub-sets of data.

For example, you can see that both our example tables contain the Name column, and some of the names are the same. Because we can cross-reference the names in the Phone table with the names in the Food table, we have the power to ask and answer such questions as, “What is the phone number of someone who likes steak?” We may also answer such questions as, “Which consumer profile purchased the most product B after buying product A?”

You can see how powerful relational data access is. The Relational Engine of PSQL provides full relational access to your data.

A join refers to an association between columns of related tables. Typically, a join operation is part of a SELECT query, which is used to obtain information from related tables.

One unique feature of PSQL is that it allows applications to access data through either the industry-standard Relational Engine, or through the ultra-high-speed MicroKernel Engine. In fact, PSQL allows applications to use both engines at the same time to access the same data.

PSQL provides a variety of methods to access data through the engines, such as the Btrieve API, ADO.NET, and ODBC. Refer to the SDK documentation for all of the access methods.

When the product and the documentation refer to the MicroKernel Engine, the terms table and database are generally not used, and data files are referred to directly as such. In addition, MicroKernel Engine users normally use the terms records and fields rather than rows and columns.

PSQL is available in different versions. The major differences between the versions are price, multiuser features, and the licensing model used.

The database engine in all of the versions is fully compatible with any PSQL database, and was designed with a common architecture. To upgrade from Workgroup to Server typically requires no changes to your application or to your database. Simply install the new version and you are ready to go. Because PSQL Vx Server uses a different license model, it requires a full installation. You cannot upgrade PSQL Server or Workgroup to PSQL Vx Server.

PSQL Workgroup offers a peer-to-peer network setup designed for stand-alone single-user installations up to small workgroups. The Workgroup engine is the only engine that offers multiuser access to PSQL data located on a computer where no database engine is installed.

A major difference between Workgroup and Server is the Gateway feature of Workgroup. When there is no database engine running on the computer where the data is located, normally the first database engine to connect to that data handles all requests from other engines to access that data. This feature can be configured so that the same Workgroup engine always services that data, or the Gateway designation can be allowed to “float” based on which Workgroup engine connects to the data first during any given work day.

The Workgroup product uses the concurrent user licensing model. See License Models.

PSQL Server offers a full client-server architecture providing performance and scalability for up to thousands of concurrent users. The Server engine can be monitored and configured remotely. The Server engine must be located on the same computer as the data files it is intended to access.

PSQL Server configuration settings are the same for engines installed on Windows, Linux, macOS, Windows Nano Server, and IoT Core systems unless otherwise noted in the documentation.

PSQL Server uses the concurrent user licensing model. For more information, see License Models. No additional license is required for use with hypervisor features such as live migration, failover, fault tolerance (FT), high availability (HA), and disaster recovery.

PSQL Vx Server has the same capabilities as PSQL Server, except that its license model supports service bureau, software-as-a-service, or other environments with multiplexed clients. PSQL Vx Server has no restrictions on hosting, connection pooling, or Internet or intranet use.

PSQL Vx Server uses the capacity-based licensing model. See License Models.

Because PSQL Vx Server is built on technology used for PSQL Server, it shares most of the database functionality and documentation of PSQL Server. Throughout the PSQL documentation, all topics for PSQL Server also apply to PSQL Vx Server unless differences are explicitly cited.

Crystal Reports is an optional product that provides rich capabilities for creating and formatting reports based on PSQL databases. Reports can be customized in thousands of ways and published as HTML, Microsoft Word document, Microsoft Excel document, or other formats.

For more information about Crystal Reports, contact your sales representative or visit the Actian PSQL website.

All PSQL documentation assumes you are familiar with the basics of using a computer, such as clicking and dragging, opening and saving files. If you need assistance with these tasks, please consult the documentation that came with your computer or operating system.

The viewer for the user documentation is integrated into PSQL Control Center (PCC). Access the documentation through the PCC interface on the Welcome view, in the Help menu, by pressing F1 (Windows) or Shift-F1 (Linux).

The following is a summary of the most commonly used books in the documentation library. The library contains other books, all of which can be accessed through the PCC interface as explained above.

Getting Started with PSQL helps you install, set up, and troubleshoot PSQL configuration. It covers the following topics:

What’s New in PSQL summarizes new features and changes in behavior for the current release of PSQL compared to the previous release. It also directs you to the documentation where the new features are fully discussed.

This guide introduces PSQL and covers common user tasks. It discusses the database engine, PSQL utilities, and other key components; the differences between Server and Workgroup engines; and the differences between ODBC and Btrieve access. It provides PSQL basics.

Advanced Operations Guide provides detailed information at the administrative level, including the steps to perform common procedures and several new ones. Topics include:

SQL Engine Reference gives database programmers a complete reference guide to the SQL relational database language. It also covers SQL engine parameters and limitations.

Status Codes and Messages documents all possible status codes and numbered messages that can be received when using PSQL.

The Status Codes Quick Reference is also included with your complete documentation set.

You can download the product documentation, white papers, technical papers, and use the online library at the Actian PSQL website.

The PSQL engine adheres to the file system security defined by the specific operating system (OS), such as Windows File Sharing.

Only the Server engine can enforce OS-level file security based on the privileges assigned to the login user name. The Workgroup product does not attempt to do this. In a small office, where Workgroup engines are most common, this can be considered a plus because they are usually short on networking experts, and the fewer barriers to successful data access the better.