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IBM Db2

IBM Db2

IBM Db2 is a data source that contains relational data.

Configure the following details for IBM Db2 data source:

Table 1. Register data source
Field Description
Display name Enter the data source name to be displayed on the screen.
Database name Enter the name of your database.
Hostname Enter the hostname.
Port Enter the port number.
Authentication type

Choose and enter the Authentication type details.

  • Username and password: Enter the username and password.
  • API key: Enter the API key.
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.
Test connection Click the Test connection link to test the data source connection. If the data source connection is successful, a success message appears.
Catalog name Enter the name of the catalog. This catalog is automatically associated with your data source.
Create Click Create to create the data source.

Select IBM Db2 from the data source section to add IBM Watson Query. You can now query the nicknames that are created in IBM Db2 and the virtualized tables from Watson Query instances.

Features

  1. You can perform the following operations for BLOB and CLOB data types for IBM Db2 data source:

    • INSERT
    • CREATE
    • CTAS
    • ALTER
    • DROP

  2. To insert CLOB data type, provide the value directly or cast it explicitly to CLOB data type.

    INSERT INTO <table_name> VALUES ('<clob value>', '<other values>');
INSERT INTO <table_name> VALUES (CAST('<clob text>' AS CLOB));

  3. To insert BLOB data, use the cast function with BLOB data type. The corresponding hexadecimal value is inserted into the IBM Db2 data source:

    INSERT INTO <table_name> VALUES (CAST('<blob text>' AS BLOB));

Limitations for SQL statements

  1. ALTER TABLE DROP COLUMN operation is not supported for column-organized tables.
  2. DROP TABLE statement is supported only when enabled in the catalog.
  3. CREATE VIEW can be used for a table only if that table is in the same catalog and the same schema.
  4. DROP SCHEMA can do RESTRICT by default.
  5. CREATE VIEW with JOINS is not supported.
  6. For data source-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

  1. BLOB and CLOB data types support SELECT statement but do not support operations such as equal, like, and in.
  2. BINARY data type supports only SELECT statement.
  3. 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 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.