PostgreSQL

IBM Cloud Databases for PostgreSQL is an open source object-relational database that is highly customizable. It’s a feature-rich enterprise database with JSON support.

Configure the following details for PostgreSQL data source:

Register data source
Field	Description
Display name	Enter the database name to be displayed on the screen.
Database name	Enter the name of your database.
Hostname	Enter the hostname.
Port	Enter the port number.
Username	Enter the username.
Password	Enter the password.
Port is SSL enabled	Use the toggle switch to enable or disable SSL connection. If enabled, i. The Upload SSL certificate (.pem, .crt, .cert or .cer) link is enabled. ii. Click the Upload SSL certificate (.pem, .crt, .cert or .cer) link. iii. Browse the SSL certificate and upload.
Validate certificate	The toggle switch must be enabled to Validate certificate. If disabled, the test connection feature does not work and the PostgreSQL database cannot be added to the engine.
Test connection	Click the Test connection link to test the database connection. If the database connection is successful, a success message appears.
Catalog name	Enter the name of the catalog. This catalog is automatically associated with your database.
Create	Click Create to create the database.

Enable the toggle switch for Validate certificate option to create the PostgreSQL database. If disabled, the Test connection feature does not work and the database cannot be added to the engine.

Limitations for SQL statements

DROP TABLE statement is supported only when enabled in the catalog.
For database-based catalogs the CREATE SCHEMA, CREATE TABLE, DROP SCHEMA, DROP TABLE, DELETE, DROP VIEW, ALTER TABLE, and ALTER SCHEMA statements are not available in the Data Manager UI.

Limitations for data types

BLOB and CLOB data types can be used as an equivalent alternative to BYTEA and TEXT respectively.
BLOB and CLOB data types support SELECT statement but do not support operations such as equal, like, and in.
The data that is shown from the UI for BLOB data type is in Base64 format, while the result from presto-cli is in hexadecimal format.
BINARY data type supports only SELECT statement.
BYTEA is the BINARY alternative data type.
When the fields of data type REAL have 6 digits or more in the decimal part with the digits being predominately zero, the values when queried are rounded off. It is observed that the rounding off occurs differently based on the precision of the values. For example, a decimal number 1.654 when rounded to 3-digits after the decimal point are the same. Another example is 10.890009 and 10.89000. It is noticed that 10.89000 is rounded to 10.89, whereas 10.89009 is not rounded off. This is an inherent issue because of the representational limitations of binary floating point formats. This might have a significant impact when querying involves sorting.