- Oracle Database – Tables, Constraints and Sequences
A CREATE TABLE worth copying, and the five constraint types. Why an unindexed foreign key locks the child table, why composite UNIQUE lets partly-null duplicates through, and the ON UPDATE CASCADE Oracle does not have. Identity columns versus sequences, CACHE and the gaps it creates, and how to drop a column on a large table.
- Oracle Database – Data Types
VARCHAR2 versus CHAR and why the BYTE/CHAR length qualifier matters in UTF-8. NUMBER precision and why money never goes in a binary float. The fact that DATE includes a time, and the range comparison that follows from it. Booleans before 23ai, the empty string that is NULL, and a full mapping table to Java types.
- Oracle Database – Users, Schemas and Privileges
In Oracle a user is a schema, so CREATE USER is how you create a namespace. Setting up a proper application account: why a tablespace quota is not optional, what CONNECT and RESOURCE really grant, the owner/role/service-account split, three ways to stop qualifying table names, and the password expiry that locks out service accounts.
- LeetCode 33 – Search in Rotated Sorted Array
A rotated array is not sorted, so binary search should not work on it. It does, because however you cut it in half at least one half is properly sorted — and telling which is a single comparison. Why that comparison needs <= and not <, the overflow-safe midpoint, and why the duplicates variant provably degrades to O(n).
- Oracle Database – Run It Locally with Docker
Oracle Database Free in a container: the image to pull, the three environment variables that matter, how to tell when the database is genuinely ready, and why you must connect to the FREEPDB1 service rather than FREE. Includes a docker-compose file with schema init scripts, and the gotchas on Apple Silicon.