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Open SQL Database DependenciesLocate this document in the navigation structure

Use

Open SQL for Java provides portability across various database platforms in such aspects as SQL statement syntax, data type mapping, and so on.

The same level of abstraction cannot be applied to the runtime behavior of database systems; issues such as statement execution time, performance, and even the successful statement execution depend on the database product, as well as on hardware resources and system configuration. For more information about certain issues, see the database product documentation.

The following are database-dependent:

  • NULL values in ORDER BY clause

    If a result set column used in an ORDER BY clause contains NULL values, the SQL standard does not specify whether the NULL values will be sorted highest or lowest. Whether a NULL value is considered greater or less than a non-NULL value is database-dependent. It is only guaranteed that all values that are NULL are either considered greater than all non-NULL values, or are considered less than all non-NULL values.

    More information about the ORDER BY clause: ORDER BY Clause

  • <in predicate>

    The number of <in value> s that an <in value list> of an <in predicate> may contain is database-dependent. The highest number of <in value> s that is supported on all databases is 256.

    More information about the <in predicate> : In predicate