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