SQL Server connector

The SQL Server connector allows querying and creating tables in an external Microsoft SQL Server database. This can be used to join data between different systems like SQL Server and Hive, or between two different SQL Server instances.

Requirements

To connect to SQL Server, you need:

• SQL Server 2012 or higher, or Azure SQL Database.

• Network access from the Trino coordinator and workers to SQL Server. Port 1433 is the default port.

Configuration

The connector can query a single database on an SQL server instance. Create a catalog properties file that specifies the SQL server connector by setting the connector.name to sqlserver.

For example, to access a database as sqlserverdb, create the file etc/catalog/sqlserverdb.properties. Replace the connection properties as appropriate for your setup:

connector.name=sqlserver
connection-url=jdbc:sqlserver://<host>:<port>;database=<database>
connection-user=root
connection-password=secret

The connection-url defines the connection information and parameters to pass to the SQL Server JDBC driver. The supported parameters for the URL are available in the SQL Server JDBC driver documentation.

The connection-user and connection-password are typically required and determine the user credentials for the connection, often a service user. You can use secrets to avoid actual values in the catalog properties files.

Multiple SQL Server databases or servers

The SQL Server connector can’t access more than one database using a single catalog.

If you have multiple databases, or want to access multiple instances of SQL Server, you need to configure one catalog for each instance.

To add another catalog:

• Add another properties file to etc/catalog

• Save it with a different name that ends in .properties

For example, if you name the property file sales.properties, Trino uses the configured connector to create a catalog named sales.

Querying SQL Server

The SQL Server connector provides access to all schemas visible to the specified user in the configured database. For the following examples, assume the SQL Server catalog is sqlserver.

You can see the available schemas by running SHOW SCHEMAS:

SHOW SCHEMAS FROM sqlserver;

If you have a schema named web, you can view the tables in this schema by running SHOW TABLES:

SHOW TABLES FROM sqlserver.web;

You can see a list of the columns in the clicks table in the web database using either of the following:

DESCRIBE sqlserver.web.clicks;
SHOW COLUMNS FROM sqlserver.web.clicks;

Finally, you can query the clicks table in the web schema:

SELECT * FROM sqlserver.web.clicks;

If you used a different name for your catalog properties file, use that catalog name instead of sqlserver in the above examples.

Type mapping

Trino supports the following SQL Server data types:

SQL Server Type	Trino Type
bigint	bigint
smallint	smallint
int	integer
float	double
char(n)	char(n)
varchar(n)	varchar(n)
date	date
datetime2(n)	timestamp(n)

Complete list of SQL Server data types.

SQL support

The connector provides read access and write access to data and metadata in SQL Server. In addition to the globally available and read operation statements, the connector supports the following features:

• INSERT

• DELETE

• Schema and table management

SQL DELETE

If a WHERE clause is specified, the DELETE operation only works if the predicate in the clause can be fully pushed down to the data source.

Pushdown

The connector supports pushdown for a number of operations:

• Join pushdown

• Limit pushdown

• Top-N pushdown

Aggregate pushdown for the following functions:

• avg()

• count()

• max()

• min()

• sum()

• stddev()

• stddev_pop()

• stddev_samp()

• variance()

• var_pop()

• var_samp()

Data compression

You can specify the data compression policy for SQL Server tables with the data_compression table property. Valid policies are NONE, ROW or PAGE.

Example:

CREATE TABLE myschema.scientists (
  recordkey VARCHAR,
  name VARCHAR,
  age BIGINT,
  birthday DATE
)
WITH (
  data_compression = 'ROW'
);