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Thomas Blum
เข้าร่วมเมื่อ 26 ต.ค. 2020
Linux Command Introduction 2: mkdir, cd, echo, touch, and ps
In this video we continue taking a fast look at some Linux commands. We used the mkdir command to create new directories (folders). We showed how a space in the folder name could be misinterpreted as wanting two different directories and how to use quotes to get a space in a name (if one is truly desired). We used the cd (change directory) command to move among the folders we created. We used the echo command to add redirect content into a file. And we used the touch command to make a new file without any content. We showed how to move both down and up in the file systems -- and talked about a directory's parent and children. Finally we looked at the ps (process) command. Without options it output the processes owned by the current user of the command line (terminal). With the -e option, it gave a much more comprehensive list of the processes running -- including many instances of the same process.
มุมมอง: 13
วีดีโอ
Linux Command Introduction: date, ls, stat, and more
มุมมอง 1814 วันที่ผ่านมา
In this video we look at an brief introduction to a few Linux commands. We start with the date command and then redirect its output to a file. We use the ls (list) command to show the file created. We use the stat command to view some of the properties and permissions assigned to that file. We use the more command to display the contents of the file. Finally we end by making the distinction bet...
Wolfram Cloud: Circle Inversion of "Interstitial Circles" on a Honeycomb Lattice
มุมมอง 3021 วันที่ผ่านมา
We use Wolfram Cloud (Mathematica) and the process of circle inversion to determine the radius of a certain circle. If six "kissing" circles surround the interior of a unit circle, those circles have a radius of 1/3. The question arose as to what was the radius of an "interstitial circle" that kissed two of these circles and the original unit circle. The problem was tackled using circle inversi...
Using HTML and JavaScript to create an SVG Quatrefoil Design
มุมมอง 3921 วันที่ผ่านมา
In this video we use JavaScript to calculate various parameters to draw a quatrefoil (four-leaf) design in SVG. The design basically consists of four arcs of circles centered on the ends of a cross shape. The challenge is to calculate where the arcs intersect and what part of the arc to draw.
Using the SQL Window Function Percent_Rank to Calculate the First, Second and Third Quartiles
มุมมอง 5021 วันที่ผ่านมา
In this video we look at using the SQL Window Function Percent_Rank to calculate the median of some data in a database table as well as the "inclusive" First and Third Quartiles. We also compare the first and third quartile calculations in Microsoft Excel, an R script, and in Wolfram/Mathematica to make clear what version of the quartiles we are producing here.
Passing JSON data from Flask/WT-Forms to Jinja to JavaScript
มุมมอง 2328 วันที่ผ่านมา
In this video we look at a demo program that has Python read a JSON file and uses it in both a server and a client context. First, on the server side that information is used to create "choices" for a WT-Forms SelectField (drop-down list). Then, on the client side, that information is passed from Python/Flask to Jinja which inserts the data into a JavaScript section of code making the informati...
SQL Queries: CASE WHEN-THEN
มุมมอง 24หลายเดือนก่อน
In this video we look at an example of using the SQL keywords: CASE, WHEN, THEN, ELSE and END. We use the w3schools online implementation of the NorthWind database. The CASE-THEN-WHEN-ELSE structure introduces a column into a query's output that takes on values depending on the conditions established by the WHEN-THEN parts WHEN condition THEN value. The last catch-all case does not require a co...
SQL Query: the EXISTS keyword
มุมมอง 13หลายเดือนก่อน
In this video we look at SQL queries using the EXISTS keyword. We start with the demo of an EXISTS query provided by the w3schools and their online implementation of the NorthWind database. An EXISTS query has a subquery but different from other queries with subqueries in that the subquery in an EXISTS query is not a proper, stand-alone query. There is a table missing from the FROM portion of t...
SQL Queries Aggregate Functions: HAVING
มุมมอง 9หลายเดือนก่อน
In this video we use the w3schools implementation of the NorthWind database to demonstrate the HAVING keyword in a SQL query. The HAVING keyword serves a similar purpose to the WHERE clause in a SQL query. However, it is used in conjunction with aggregation queries (such as those with COUNT or SUM) and GROUP BY. In fact we re-write a query with HAVING as a query containing a sub-query and a WHE...
Database Security: Part 2
มุมมอง 35หลายเดือนก่อน
In this second video on database security we focus on encryption and firewalls. Encryption applies some parametrized, invertible function (e.g. something simple like ADD 3) to turn plaintext (readable) into cyphertext (unreadable). The inverse process (either SUBTRACT 3 or ADD -3) converts the cyphertext back into plaintext. In symmetric encryption knowing the parameter ("key") for encrypting d...
Database Security: Part 1
มุมมอง 13หลายเดือนก่อน
In this video we look at an introduction to database security. A security policy should lay out the balancing of providing access to the data and protecting the data as one of an enterprise's assets. It lists some common threats (involving hardware, software, and people) and some countermeasures. It mentions authorization and views as means of assigning very specific access to users. It then go...
Data Definition Language: Part 2
มุมมอง 20หลายเดือนก่อน
In a previous video we looked at the parts of SQL that defined an attribute (column, property, field) its name, type, domain, and so on. In this video we talk about the part of the Data Definition Language that brings together the attributes to create a table. In addition we consider the role played by certain fields or combinations of fields such a PRIMARY KEY and its role in maintaining Entit...
Data Definition Language (DDL): Part 1
มุมมอง 10หลายเดือนก่อน
In this video we start to look at the DDL (Data Definition Language) part of SQL (Structured Query Language). The DDL is what is used to CREATE a database to specify what data will be collected, what values are allowed, and so on. We start with the narrowest part defining attributes. To start an attribute has a name or identifier. Next, it has a type to limit the sort of values that are expecte...
Database Transactions: Part 3
มุมมอง 11หลายเดือนก่อน
In this video we look at a mechanism for preventing two database transactions from interfering with each other and leading to inconsistent results. A transaction can request a "lock" on data it intends to use in a transaction. The lock might be "shared" if the transaction will only read (SELECT) the data, but the lock will be "exclusive" if the transaction will write data (UPDATE). Two-phase lo...
Database Transactions: Part 2
มุมมอง 14หลายเดือนก่อน
In this video we look at some scenarios in which two transactions can interfere with each other. Thus they would not pass the ACID test, as they are not I "isolated". If two transactions only read data (SELECT), they do not interfere. If two transactions involve completely different sets of data, they don't interfere. Otherwise, we should ask if the two transactions are "serializable" consisten...
VS Code: Importing CSV files to make a SQLite Database
มุมมอง 189หลายเดือนก่อน
VS Code: Importing CSV files to make a SQLite Database
VS Code: Writing and Running a SQL Script
มุมมอง 40หลายเดือนก่อน
VS Code: Writing and Running a SQL Script
VS Code: Creating a SQLite Database from a SQL Script
มุมมอง 68หลายเดือนก่อน
VS Code: Creating a SQLite Database from a SQL Script
SQL Queries Aggregate Functions: AVG, MAX, and MIN
มุมมอง 15หลายเดือนก่อน
SQL Queries Aggregate Functions: AVG, MAX, and MIN
SQL Queries Aggregate Functions: COUNT and GROUP BY
มุมมอง 14หลายเดือนก่อน
SQL Queries Aggregate Functions: COUNT and GROUP BY
SQL Queries: Inner Joins vs Outer Joins (Left and Right)
มุมมอง 60หลายเดือนก่อน
SQL Queries: Inner Joins vs Outer Joins (Left and Right)
Using VS-Code and SQLite3 Editor: Fixing a SQL Create Script
มุมมอง 582 หลายเดือนก่อน
Using VS-Code and SQLite3 Editor: Fixing a SQL Create Script
Thank you for showing this. As a relative beginner, I'd like to ask what is the advantage of doing this work in VS Code instead of a dedicated SQL editor like MySQL Workbench or Navicat?
There are two choices here. The first is to use SQLite as a database, and the second is to use VS Code as an IDE. Because SQLite is "sever-less" (en.wikipedia.org/wiki/SQLite), it is easier for our IT department to install in our labs and for the students to have it on their own devices. I find it is good enough to teach database basics and development provided one is not taking any project all the way to production or specifically interested in client-server and multi-user aspects of the database. As for VS Code, it is becoming my go-to IDE mainly because of its extensibility. I can use it when I teach database, when I teach Python, and when I teach JavaScript. Furthermore, I can get it to act as if it were a server when I need that.
Thank you
C'mon you can't be explaining Linux commands on a windows machine 😢
Thank you.
how do you change the input bits?
Thank you for the video
th-cam.com/video/1DeYvCq9wQM/w-d-xo.html
www1.lasalle.edu/~blum/c152wks/Circle_Inversion_Honeycomb_Interstitials.pdf
www1.lasalle.edu/~blum/c343wks/SVG_Quatrefoil.html
When I put double curly braces in the script, it gives a syntax error and there is another trouble that it shows error in the network which is caused because it takes the html as a json
I have only used the code in the context of a Python/Flask development server using the VS Code environment. And as you saw, there it worked. The double-curly is Jinja, and I don't recall installing anything beyond Flask (and WT-Forms) to make it understood.
www1.lasalle.edu/~blum/c240wks/SQL_PercentRank_Quartiles.zip
www1.lasalle.edu/~blum/c341wks/ComforterDemo.zip
Thank you
www1.lasalle.edu/~blum/c240wks/DatabaseSecurity_B.pptx
www1.lasalle.edu/~blum/c240wks/DatabaseSecurity_A.pptx
www1.lasalle.edu/~blum/c240wks/DDL_B.pptx
www1.lasalle.edu/~blum/c240wks/DDL_A.pptx
www1.lasalle.edu/~blum/c240wks/Transactions_C.pptx
www1.lasalle.edu/~blum/c240wks/Transactions_B.pptx
www1.lasalle.edu/~blum/c240wks/Transactions_A.pptx
www1.lasalle.edu/~blum/c240wks/classicModels_CSV_files.zip
www1.lasalle.edu/~blum/c240wks/StatePopulation.txt
www1.lasalle.edu/~blum/c240wks/AuthorMultiInsert.zip
www1.lasalle.edu/~blum/c240wks/Quote_SQL_script_A.zip
www1.lasalle.edu/~blum/c240wks/Lab_VSCode_SQLite_Script_A.pptx
Wonderful explanation, thank you!
thank you! it was very helpful
www1.lasalle.edu/~blum/c152wks/Lab_20D_Grade_Calculation_rev.xlsx
www1.lasalle.edu/~blum/c240wks/In_Class_Users_ER_Modeling.docx
www1.lasalle.edu/~blum/c240wks/Lab7A_ArtForSale.docx
www1.lasalle.edu/~blum/c240wks/FacultyBookOrderThirdNormal.doc
www1.lasalle.edu/~blum/c341wks/tkinter_bigcats.zip
www1.lasalle.edu/~blum/c240wks/MoreOnNormalization_3.pptx
www1.lasalle.edu/~blum/c240wks/MoreOnNormalization_2.pptx
www1.lasalle.edu/~blum/c240wks/MoreOnNormalization_1.pptx
www1.lasalle.edu/~blum/c152wks/Lorentzian_Fit.xlsx
www1.lasalle.edu/~blum/c240wks/StarWars_2NF.docx
www1.lasalle.edu/~blum/c240wks/StudentTranscriptsSecondNormal_inclass.docx
www1.lasalle.edu/~blum/c343wks/SVG_Georgy_Girl.html
Thanks a lot, i couldn't make chat gpt draw a heart lol, i gave him the html code from the page and he then did just fine !
Glad it was useful (even if it wasn't the way I expected it to be used).
www1.lasalle.edu/~blum/c152wks/Lab_12D_NuclearDecaySimulation_no_voice.pptx
www1.lasalle.edu/~blum/c152wks/Lab_12C_RandomWalkSimulation_no_voice.pptx
www1.lasalle.edu/~blum/c152wks/Lab_13B_R_fitting_to_power_law_no_voice.pptx
www1.lasalle.edu/~blum/c152wks/Lab_13D_LatitudeLongitude_no_voice.pptx
now create a coordinate system for it
frank-buss.de/hat/
www1.lasalle.edu/~blum/c240wks/Normalization_2.pptx
www1.lasalle.edu/~blum/c240wks/Normalization_1.pptx
thanks for sharing!
www1.lasalle.edu/~blum/c240wks/DataModels_03.pptx