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Designing databasesThe first step in creating a relational database is to construct a data model, which is a precise, complete definition of the data you want to store. After you prepare your data model, you must implement it as a database and tables. To implement your data model, you first select a data type for each column and then you create a database and tables and populate the tables with data. You can also implement fragmentation strategies and control access to your data.
Designing and Implementing a DatabaseThe HCL OneDB™ Database Design and Implementation Guide provides information to help you design, implement, and manage your HCL® OneDB® databases. It includes data models that illustrate different approaches to database design and shows you how to use structured query language (SQL) to implement and manage your databases.
Object-relational databases
Create and use user-defined casts
What is a cast?
Invoke casts

Invoke casts

For built-in casts and user-defined implicit casts, the database server automatically (implicitly) invokes the cast to handle the data conversion. For example, you can compare a value of type INT with SMALLINT, FLOAT, or CHAR values without explicitly casting the expression because the database server provides system-defined casts to transparently handle conversions between these built-in data types.

When you define an explicit user-defined cast to handle conversions between two data types, you must explicitly invoke the cast with either the CAST...AS keywords or the double-colon cast operator (::). The following partial examples show the two ways that you can invoke an explicit cast:

... WHERE new_col = CAST(old_col AS newtype)

... WHERE new_col = old_col::newtype

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