Data Definition Language (DDL) data densification data dictionary view, USER_UPDATABLE_COLUMNS Data Manipulation Language [See DML] data types DATE converting default format internal storage format NULL values and specifying format object types parameters tables data warehouse applications, group operations and Database 10g collections optimization of partitioning databases engines group operations aggregate functions DISTINCT/ALL GROUP BY clause HAVING clause nested parameters time zones DATE data type converting default format format, specifying internal storage format NULL values and dates arithmetic addition overview subtraction case-sensitivity format codes formatting interval data INTERVAL DAY TO SECOND data type INTERVAL YEAR TO MONTH data type ISO standards overview weeks years literals pivot tables, creating ranges, SELECT statement rounding/truncating RTRIM function summarizing by time zones database overview session working days, calculating years AD/BC indicators two-digit DAY TO SECOND interval literal days (working), calculating dbms_xmlschema.registerSchema( ) built-in procedure DBTIMEZONE function keyword DDL (Data Definition Language) Decision Support Systems [See DSS] DECODE function divide by zero errors errors optional updates result sets, transforming selective aggregation selective function execution state, controlling syntax 2nd UPDATE statement default date format definitions, objects DELETE statement DML join views multiple-column subqueries scalar subqueries deleting duplicate result sets subpartitions subtrees denormalizations, conditional updates DENSE_RANK function 2nd dependency graphs deterministic functions DIMENSION BY clause 2nd DISTINCT keyword aggregate functions compared to EXISTS divide by zero errors, avoiding DML (Data Manipulation Language) DELETE statement INSERT statement join views multilevel collections partitions, specifying SELECT statement clause references DISTINCT keyword ORDER BY clause WHERE clause statements (inline views) stored functions and UPDATE statement documents (XML) generating overview of storing data updating DSS (Decision Support Systems) queries compared to SQL SQL and