全部博文(69)
发布时间:2017-10-30 03:18:46
SELECT SUBSTR(TABSCHEMA,1,18) TABSCHEMA,SUBSTR(TABNAME,1,30) TABNAME,(DATA_OBJECT_P_SIZE + INDEX_OBJECT_P_SIZE + LONG_OBJECT_P_SIZE + LOB_OBJECT_P_SIZE + XML_OBJECT_P_SIZE) AS TOTAL_SIZE_IN_KB,(DATA_OBJECT_P_SIZE + INDEX_OBJECT_P_SIZE + LONG_OBJECT_P_SIZE + LOB_OBJECT_P_SIZE + XML_OBJECT_P_SIZE)/.........【阅读全文】
发布时间:2016-08-26 04:53:23
There are quite some perspectives need to keep in mind when writing SQL Queries:1. Avoid including data type conversion in joining conditions2. Avoid using function in joining conditions3. Avoid using negtive joining conditions4. Keep the joining conditions in the same data type......【阅读全文】
发布时间:2016-08-13 05:11:42
Suppose the database stores information about actors, together with theirnames, birthdays, and ratings, where ratings can change over time:According to anchor modeling, each attribute should go into its own table:the 'anchor' table which only has a synthetic primary key:create tab.........【阅读全文】
发布时间:2016-08-12 08:17:19
To execute DB2 UDB Admin Functions to work in IBM Data Studio, you can use the SYSPROC.ADMIN_CMD procedure which will work through most of the JDBC drivers. 1. Open a query editor in Data Studio to your DB2 Server2. Use the ADMIN_CMD procedure CALL SYSPROC.ADMIN_CMD()3. .........【阅读全文】
发布时间:2015-12-31 07:19:19
In db2, null could be anything. But some time when we join tables by using join condition which involves null values, we should remember that :a.cola = b.colb -- if both are null, the condition is false, that is null = null returns false.a.cola <> b.colb -- if both ar.........【阅读全文】