Merge dd2d37026e into 88e5be6e4b

databases/oracledb.sh

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+*****************************************************************************
+BASICS
+*****************************************************************************
+
+# Connect to Oracle Database
+Establish a connection to the Oracle Database using SQL*Plus. Replace username, password, hostname, port, and service_name with the appropriate values.
+
+sqlplus username/password@hostname:port/service_name
+
+
+# Show All Schemas
+Retrieve a list of all schemas in the Oracle Database.
+ 
+SELECT username FROM all_users;
+
+# Show Current Schema
+Display the current schema (user) in use.
+ 
+SHOW USER;
+
+# Create Schema (User)
+Create a new schema (user) in the Oracle Database.
+ 
+CREATE USER username IDENTIFIED BY password;
+
+# Switch Schema
+Change the current schema for the session.
+ 
+ALTER SESSION SET CURRENT_SCHEMA = username;
+
+# Drop Schema (User)
+Remove a schema (user) from the Oracle Database, including all owned objects.
+ 
+DROP USER username CASCADE;
+
+# Show Tables in Current Schema
+Retrieve a list of tables in the current schema.
+ 
+SELECT table_name FROM user_tables;
+
+*****************************************************************************
+CRUD
+*****************************************************************************
+
+# Create Table
+Define and create a new table in the Oracle Database.
+ 
+CREATE TABLE table_name (
+  column1 datatype,
+  column2 datatype,
+  ...
+);
+
+# Insert Row
+Add a new row with specified values into a table.
+ 
+INSERT INTO table_name (column1, column2, ...) VALUES (value1, value2, ...);
+
+# Select All Rows
+Retrieve all rows from a table.
+ 
+SELECT * FROM table_name;
+
+# Select Specific Columns
+Retrieve specific columns from a table.
+ 
+SELECT column1, column2 FROM table_name;
+
+# Update Row
+Modify data in a table by updating a specific row.
+ 
+UPDATE table_name SET column1 = value1 WHERE condition;
+
+# Delete Row
+Remove specific rows from a table based on a condition.
+ 
+DELETE FROM table_name WHERE condition;
+
+*****************************************************************************
+OTHER FUNCTIONS
+*****************************************************************************
+
+# Sort Rows
+Retrieve rows from a table sorted in ascending or descending order based on a specified column.
+ 
+SELECT * FROM table_name ORDER BY column1 [ASC|DESC];
+
+# Count Rows
+Calculate the total number of rows in a table.
+ 
+SELECT COUNT(*) FROM table_name;
+
+# Limit Rows
+Restrict the number of rows retrieved from a table.
+ 
+SELECT * FROM table_name WHERE ROWNUM <= n;
+
+# Join Tables
+Combine rows from two or more tables based on a related column.
+ 
+SELECT * FROM table1 JOIN table2 ON table1.column = table2.column;
+
+# Group By
+Group rows based on the values in a specified column and perform an aggregate function.
+ 
+SELECT column, COUNT(*) FROM table_name GROUP BY column;
+
+# Aggregate Functions
+Perform aggregate calculations on a column, such as average, sum, minimum, and maximum.
+ 
+SELECT AVG(column), SUM(column), MIN(column), MAX(column) FROM table_name;
+
+# Subquery
+Use the result of a subquery to filter data in the main query.
+ 
+SELECT column1 FROM table_name WHERE column2 = (SELECT column2 FROM another_table WHERE condition);
+
+# Index
+Create an index on a column to improve query performance.
+ 
+CREATE INDEX index_name ON table_name(column1);
+
+# Drop Index
+Remove an existing index from a table.
+ 
+DROP INDEX index_name;
+
+# Constraints
+Enforce data integrity by adding a primary key constraint to a table.
+ 
+ALTER TABLE table_name ADD CONSTRAINT constraint_name PRIMARY KEY (column1);
+
+# Sequence
+Create a sequence that generates unique values for a column.
+ 
+CREATE SEQUENCE sequence_name START WITH 1 INCREMENT BY 1;
+
+# View
+Create a virtual table based on the result of a SELECT query.
+ 
+CREATE VIEW view_name AS SELECT column1, column2 FROM table_name WHERE condition;
+
+# Stored Procedure
+Define and store a reusable set of SQL statements in the database.
+ 
+CREATE OR REPLACE PROCEDURE procedure_name (parameter1 datatype, parameter2 datatype, ...) AS
+BEGIN
+  -- procedure body
+END;
+/
+
+# Trigger
+Associate a set of actions with a specific table event, such as before inserting a new row.
+ 
+CREATE OR REPLACE TRIGGER trigger_name
+BEFORE INSERT ON table_name
+FOR EACH ROW
+BEGIN
+  -- trigger body
+END;
+/
+
+# Partitioning
+Divide a large table into smaller, more manageable pieces for improved performance and maintenance.
+ 
+CREATE TABLE table_name
+PARTITION BY RANGE (column_name)
+(
+  PARTITION part1 VALUES LESS THAN (value1),
+  PARTITION part2 VALUES LESS THAN (value2),
+  ...
+);