Linux patching (OS security updates, kernel upgrades, etc.) is a routine activity for system administrators. For Oracle RAC environments, DBAs must ensure pre-patching checks, safe shutdowns, and post-patch relinks are properly executed to avoid service disruption. 1. Why Pre-Patching Checks Are Critical Before handing over the server to the Linux team, DBAs must: These pre-checks […]
When working with ROLLUP or CUBE, you’ll notice NULL values appear in subtotals and grand totals.But how do you tell the difference between a real NULL value in the data and a NULL that just means “subtotal here”? That’s where GROUPING_ID comes in. It returns a numeric code indicating which columns are aggregated (rolled up). […]
SQL provides powerful extensions to GROUP BY: ROLLUP and CUBE. These are extremely useful for building reports with subtotals and cross-tab summaries. Let’s see some practical examples. Example 1: Total Salaries with ROLLUP by Department and Job This query calculates total salaries: Output: The hierarchy is clear: job totals roll up into department totals, which […]
Oracle Core DBA A Core DBA traditionally manages on-premises databases. Their toolset revolves around direct database administration, storage, networking, and operating system integration. Common Tools Used by Core DBAs Cloud Ops DBA A Cloud Ops DBA works in cloud-native or hybrid environments. They still use Oracle database tools, but the scope expands to cloud provider […]