Oracle SQL is the structured query language used to communicate with Oracle databases, enabling data retrieval, manipulation, and management.
A table is a database object that stores data in rows and columns. Each row represents a record, and each column represents a field.
A primary key is a column or set of columns that uniquely identifies each row in a table. It enforces uniqueness and does not allow null values.
A foreign key is a column or set of columns in one table that refers to the primary key in another table, creating a relationship between the two tables.
Constraints are rules applied to table columns to enforce data integrity. Common constraints include PRIMARY KEY, FOREIGN KEY, UNIQUE, NOT NULL, and CHECK.
A view is a virtual table based on the result of an SQL query. It does not store data physically but provides a way to look at data from one or more tables.
A join is a query that combines rows from two or more tables based on a related column. Common types include INNER JOIN, LEFT JOIN, RIGHT JOIN, and FULL OUTER JOIN.
Aggregate functions perform calculations on multiple rows and return a single result. Common aggregate functions include SUM(), AVG(), COUNT(), MAX(), and MIN().
The GROUP BY clause is used to group rows with the same values in specified columns and apply aggregate functions to each group.
A sequence is a database object that generates a series of unique numbers, typically used for primary keys.
Indexes are database objects that improve query performance by allowing faster retrieval of rows. Common index types include B-tree, Bitmap, and Unique.
A cursor is a pointer to a result set of a query. It is used to process rows returned by the query one at a time.
An implicit cursor is automatically created by Oracle when a query is executed, whereas an explicit cursor must be declared and opened by the user to retrieve multiple rows.
Synonyms are aliases for database objects such as tables, views, sequences, or functions, used to simplify access.
Normalization is the process of organizing a database into tables and columns to reduce data redundancy and improve data integrity.
Denormalization is the process of combining tables to reduce the complexity of queries and improve performance by adding redundancy.
A PL/SQL block is a logical unit of code that contains procedural language constructs like variables, conditions, loops, and SQL statements. It has three parts: Declaration, Execution, and Exception handling.
ROWNUM is a pseudo-column that assigns a unique number to each row returned by a query.
DELETE removes rows from a table and can be rolled back, while TRUNCATE removes all rows from a table but cannot be rolled back.
Partitioning is a database feature that divides large tables into smaller, more manageable pieces, improving performance and scalability.
