added cheat sheets

MarkDownToPdfScript/main.ts

@@ -35,6 +35,9 @@ export const work = async (source: string, target: string): Promise<void> => {
     .access(targetDir)
     .catch(() => fsp.mkdir(targetDir, { recursive: true }));
 
+  console.log(pdfBufferArray);
+  return;
+
   const zipFile = new AdmZip();
   pdfBufferArray.forEach((e) => e && zipFile.addFile(e.name, e.file));
   zipFile.writeZip(target);

Markdown/Advanced-Databases/Advanced/README.md

@@ -0,0 +1,176 @@
+
+# Nested Queries 
+
+|  With Select  | With Update | With Insert | With Delete |
+| --- | --- | --- | --- |
+| ``SELECT (SELECT query that returns one value) FROM table  WHERE conditions``  <br />  <br /> ``SELECT columns FROM (SELECT query that retuns multiple rows ) WHERE condition``  <br />  <br />  `` SELECT column_name FROM   tables  WHERE  column_name OPERATOR  (SELECT Query)`` | ``UPDATE table SET column_name = new_value WHERE OPERATOR (SELECT Query)``| ``INSERT INTO table_name [ (columns..) ]  VALUES (SELECT Query that reurns one value , [val , ...])``  | ``DELETE FROM TABLE_NAME WHERE OPERATOR (SELECT Query)`` |
+<!--## With Select
+       SELECT ( SELECT Query that returns one value 
+      // Don't forget to make the join condition with the table called in the main select )
+       FROM table 
+       WHERE conditions 
+  ------------------------------    
+       SELECT columns 
+       FROM (SELECT query that retuns multiple values )
+       WHERE condition
+---------------------------------------
+      SELECT column_name
+      FROM   tables 
+      WHERE  column_name OPERATOR  (SELECT Query)
+## With Update 
+       UPDATE table
+      SET column_name = new_value
+      WHERE OPERATOR [ VALUE ] (SELECT Query)
+## With Insert 
+       INSERT INTO table_name [ (columns..) ] 
+       VALUES (SELECT Query that reurns one value , [val , ...]) 
+   ## With Delete
+       DELETE FROM TABLE_NAME
+       WHERE OPERATOR (SELECT Query)
+-->
+ **OPERATOR**  : EXISTS / NOT EXISTS  -- BETWEEN -- IN 
+
+
+# Views 
+### Creation
+#### Virtual View 
+- ``CREATE VIEW view_name(col1,col2,..) AS  query  [WITH CHECK OPTION] [WITH READ ONLY] ``
+- `` REPLACE VIEW view_name(cols) AS query  [WITH CHECK OPTION] [WITH READ ONLY]``
+#### Concrete View 
+- ``CREATE CONCRETE VIEW view_name(col1,col2,..) AS  query  [WITH CHECK OPTION] [WITH READ ONLY] ``
+
+### Delete
+- `` DROP VIEW view_name ``
+# Recursive Queries (^SQL3)
+
+     WITH [RECURSIVE] name AS (
+     Initialisation Query 
+     UNION ALL
+     Recursive Query with terminate condition in where 
+     )
+     SELECT * from name; -- Displaying result data 
+     
+     
+- PostgreSQL requires the RECURSIVE keyword in recursive definitions but it is optional for other databases.
+
+<img height=300 src='https://cdn.sqlservertutorial.net/wp-content/uploads/SQL-Server-Recursive-CTE-execution-flow.png' >
+
+# PL/SQL 
+
+ ``DECLARE``<br /> ``VarName [constant] type [:= val];``<br /> ``BEGIN``<br />``EXCEPTION``<br />``END`` 
+
+
+# Functions and Procedures 
+## Functions 
+|Oracle | PostgreSQL |
+| --- | --- |
+| ``CREATE FUNCTION func_name[(in / out / in out parms)] RETURN returnType AS``<br /> ``DECLARE``<br /> ``VarName [constant] type [:= val];``<br /> ``BEGIN``<br />``-- SELECT must always be used with INTO``<br />``RETURN statement``<br />``EXCEPTION``<br />``END``|``CREATE FUNCTION func_name() RETURNS returnType AS $$``<br />``DECLARE``<br />``VarName [constant] type [:= val];``<br /> ``BEGIN``<br />``RETURN statement``<br />``EXCEPTION``<br />``END``<br />``$$ LANGUAGE plpgsql;``| 
+     
+          
+  ## Procedures
+
+  |Oracle | PostgreSQL |
+| --- | --- |
+| ``CREATE procedure proc_name[(in / out / in out parms)] AS ``<br /> ``DECLARE``<br /> ``VarName [constant] type [:= val];``<br /> ``BEGIN``<br />``-- SELECT must always be used with INTO``<br />``RETURN statement``<br />``EXCEPTION``<br />``END proc_name;``|``CREATE Procedure prod_name() AS $$``<br />``DECLARE``<br />``VarName [constant] type [:= val];``<br /> ``BEGIN``<br />``EXCEPTION``<br />``END``<br />``$$ LANGUAGE plpgsql;``| 
+     
+
+
+
+- Var Types
+    - RECORD, INTEGER , VARCHAR(n) , CHAR ,DATE , DECIMAL ... 
+    - TABLES , LINE ..
+    - %TYPE  %ROWTYPE
+### Custom Type : 
+            
+            CREATE TYPE type_name AS (
+            var_name    var_type ,
+              );
+              
+- Return Types:     
+     - INTEGER , VARCHAR(n) , CHAR ,DATE , DECIMAL ... 
+     - setof (type) : return more then one row
+
+   **Example:** 
+
+            CREATE OR REPLACE function cat() RETURNS setof varchar language plpgsql as $$
+            DECLARE 
+              liste CURSOR for SELECT tablename FROM pg_tables where tableowner='root';
+              tablename RECORD ;
+              BEGIN
+
+              for tablename in liste 
+              loop 
+              return NEXT tablename.tablename ;
+              end loop;
+
+              END 
+               $$;
+
+
+# Triggers
+
+       CREATE TRIGGER trigger_name
+       {BEFORE | AFTER} {INSERT | UPDATE| DELETE } [OF colums]
+       ON table_name
+       [REFERENCING {OLD | NEW | PARENT } [ROW] [AS] alias]
+       [FOR EACH ROW]
+          
+        --trigger_body (pl/sql bloc) 
+        or
+        --calling a function (EXECUTE PROCEDURE func_name();) ; 
+        this function should RETURN a TRIGGER
+
+# Cursor
+ - It helps you store multiple lines and Mange access to them
+
+### Creation
+
+
+|Oracle |PostgreSQL|
+| ----- | ----- |
+|``CURSOR cursorname IS SELECT ..FROM .. WHERE..``<br />``FOR UPDATE/DELETE [OF Column list ]][NOWAIT WAIT duration]``|``cursorname CURSOR  FOR Query``|
+
+### Iterating Rows
+
+
+|Oracle |PostgreSQL|
+| ----- | ----- |
+|``FOR record_variable IN cursor_variable`` <br/>``LOOP``<br/>``...``<br/> ``END LOOP;``|``LOOP``<br/>``FETCH FROM cursor_variable INTO record_variable;``<br/>``EXIT WHEN NOT FOUND;``<br/>``...``<br />``END LOOP;``|
+
+In PostgreSQL : we should open the Cursor after Declation 
+
+# Exceptions
+
+we add exceptions within a PL/SQL bloc : 
+
+       DECLARE 
+       -- Variables, curseurs, exceptions définies par l'utilisateur
+       BEGIN *
+
+       -- Instructions 
+
+       EXCEPTION (facultatif)
+       -- Actions à effectuer lorsque des erreurs se produisent
+       END; *
+  -------------------------------------       
+         
+      EXCEPTION 
+      WHEN DefinedException | costum exception THEN
+      statement;
+      ...
+
+      WHEN OTHERS THEN
+      statement;
+
+
+  - Defined exception
+      - NO_DATA_FOUND 
+      - TOO_MANY_ROWS
+      - ..
+ - Custom exception in oracle: 
+      - **Declaration** : ``exception_name EXCEPTION; ``
+      - **Raising an exception** : ``RAISE  exception_name;``
+
+ - Custom exception in PostgreSQL: 
+           ``raise exception '%','Exception text';``
+

Markdown/Advanced-Databases/Beginner/README.md

@@ -0,0 +1,117 @@
+
+# Managing Users
+  - ``GRANT privileges ON table TO user (PUBLIC) [WITH GRANT OPTION ]``
+  - ``REVOKE privileges ON table FROM user``
+- Privileges: 
+
+
+|`` ALL PREVILEGES``|``UPDATE (columns)``|``SELECT (columns)``|``INSERT (columns)``|``DELETE (columns)``|``ALTER (columns)``| `` INDEX``|
+| --- | --- | --- | --- | --- | --- | --- |
+
+
+###  ROLES : 
+- ``
+    CREATE ROLE role_name; 
+``
+- `` 
+   GRANT previlege ON table TO role; 
+``
+- ``  
+ GRANT role TO user; 
+``
+
+# Managing Tables
+
+## Creation 
+  - ``CREATE TABLE table_name ( column_name  [TYPE] [COLUMN_CONSTRAINT]  , [TABLE CONSTRAINT] [REFRENTIAL CONSTAINT]);``
+
+       - **TABLE CONSTRAINT** :
+         - ``CONSTRAINT`` const_name ``CONST_TYPE`` (Column1, column2,... )
+      - **COLUMN CONSTRAINT**: 
+      [CONSTRAINT constraint_name]
+          -  `` AUTO_INCREMENT ``
+         -  ``UNIQUE``
+         -  ``NULL`` / ``NOT NULL`` 
+         -  ``DEFAULT``'val'
+         -  ``PRIMARY KEY``
+         -  ``REFRENCES`` 'table_name'
+         -  ``CHECK`` 'constraint'
+
+      - **REFERENCIAL CONSTRAINT** :
+        - ``FOREIGN KEY``(column_name) ``REFERENCES`` table_name(primarykey) [FOREIGN KEY CONSTRAINT]
+        - **FOREIGN KEY CONSTRAINT**: 
+           - ``ON DELETE`` {CASCADE/SET NULL/ SET DEFAULT}
+           - ``ON UPDATE`` {CASCADE/SET NULL/ SET DEFAULT}   
+
+      - **TYPE**: 
+        - ``VARCHAR(n)``
+        - ``INTEGER`` 
+        - ``BOOL``
+        - ``DATE``
+        - ``DATETIME``
+
+  ##### FIND MORE: `https://www.w3schools.com/sql/sql_datatypes.asp`
+       
+                  
+## Modification
+- ``ALTER TABLE table_name [OPERATION];``
+
+
+    - OPERATIONS :
+      - `` RENAME TO`` new_table_name
+      - ``RENAME COLUMN`` column_name ``TO`` new_name
+      - ``DROP COLUMN`` column_name
+      - ``DROP CONSTRAINT`` const_name
+      - ``ADD COLUMN`` column_name
+      - ``ADD CONSTRAINT`` constraint_details
+      - ``MODIFY COLUMN`` column_name
+
+
+## Delete 
+  - ``DROP TABLE Table_name {CASCADE CONSTRAINT | RESTRICT };``
+# Managing Data
+## SELECT 
+
+     SELECT {DISTINCT | ALL} columns
+     FROM tables 
+     WHERE conditions
+     GROUP BY columns 
+     HAVING conditions
+     [UNION | INTERSECT | MINUS <sub-Query>]
+     ORDER BY columns 
+     
+ ### Operations can be used in ``WHERE`` and ``HAVING`` clause 
+
+ |< , > , = ,<= , >= , <>|LIKE|IS NULL|IN (va1, val)|BETWEEN n1 AND n2|
+ | --- | --- | --- | --- | --- |
+
+
+### Functions can be used in ``SELECT`` statement, ``WHERE`` and ``ORDER BY`` clause
+
+1 - **Multiple-Row Functions** : Aggregate Functions
+
+ | SUM|AVG|MIN|MAX|COUNT|
+ | --- | --- | --- | --- | --- |
+
+
+2  - **Single-Row functions** 
+
+   - UPPER, LOWER , INITCAP
+   - CONCAT, LENGTH, SUBSTR, INSTR, LPAD, RPAD, TRIM , REPLACE.
+   - MONTHS_BETWEEN, ADD_MONTHS, NEXT_DAY, LAST_DAY, CURTIME , DATE_FORMAT(date, format) ,YEAR(date)
+   - ROUND, TRUNC, MOD.
+
+  See More : https://docs.oracle.com/database/121/SQLRF/functions002.htm#SQLRF51178
+
+## UPDATE
+- ``
+  UPDATE table 
+  SET changes
+  WHERE condition
+  ``
+## INSERT
+
+- ``INSET INTO table_name (col1, col2, ...) VALUES (val1, val2 ,...);``
+
+## DELETE
+- ``DELETE FROM table_name WHERE condition``