Indicator Variables

最新推荐文章于 2024-09-02 14:08:42 发布

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#variables #null #processing #db2 #insert #sql

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本文详细介绍了DB2中Indicator Variables的作用及使用方法。包括处理NULL数据的功能、不同值所代表的意义，以及在SQL语句中如何被设置或利用。

Indicator Variables

1. Function: Processing NULL Data

2. The value of Indicator Variable (SMALLINT)

l >=0 (usually 0), indicate that the column is not NULL

l <0 (usually -1), indicate that the column is NULL

l -2, indicate that the column value can’t be stored in host variable for the reason that numeric conversion could not be performed or arithmetic expression error occurred

l -3, indicate that a hole was detected for the row on a multiple row FETCH, and values were not returned for the row. SQLCODE +222, is also returned for that row.

3. Indicator Variable Usage

l When using SELECT or FETCH statement in SQL, indicator variables are set by DB2 according to the property of the relevant column(NULL or NOT NULL)

l When using UPDATE or INSERT statement in SQL, the programmer need to set the value of indicator variables to tell DB2 that the relevant column is NULL or NOT NULL