Feldera only supports two kinds of SQL Data Definition Language (DDL) statements: table definitions, and view definitions. Each table definition becomes an input, and each view definition becomes an output. Here is an example program:

CREATE TABLE Person
(
    name    VARCHAR,
    age     INT,
    present BOOLEAN
);
CREATE MATERIALIZED VIEW Adult AS SELECT Person.name, Person.age FROM Person WHERE Person.age > 18;

Statements need to be separated by semicolons.

Feldera is optimized for performing incremental view maintenance. In consequence, Feldera programs in SQL are expressed as VIEWS, or standing queries. A view is a virtual table that is formed by a query on other tables or views.

For example, the following query defines a view:

CREATE MATERIALIZED VIEW Adult AS SELECT Person.name FROM Person WHERE Person.age > 18

In order to interpret this query the compiler needs to have been given a definition of table (or view) Person. The table Person must be defined using a SQL DDL statement, e.g.:

CREATE TABLE Person
(
    name    VARCHAR,
    age     INT,
    present BOOLEAN
)