Adding images to Postgresql through simple MS Access forms

It seems like there is no simple method for doing this task. Postgresql’s ‘bytea’ datatype field is resolved in MS Access linked table as ‘binary’ where simple image uploading method is not even available. There are also reports that already saved images in Postgresql are not resolved as images in the linked ‘binary’ field of MS Access forms and reports.

Adding images to postgresql database is also not cost effective. For the moderate number of images to be added through the application, it is better to make local MS Access tables for images by using ‘attachment’ data type. Thus, for images/documents etc. it is better to make local MS Access field (attachment). Image data will reside on local MS Access. All other data would reside in Postgresql server. It will be better for server resources and cost will not pile up for cloud due to images. Retrieval of images being local will also be fast.

Auto Increment (Postgresql) Vs. AutoNumber (MS Access)

In Postgresql, prefer making Auto Increment for the table right from start. Following is code for a test table:

CREATE TABLE test_table(

    test_id SERIAL PRIMARY KEY

);

I wrote above code in pgAdmin 4 >> Tools >> Query Tool

Executing this query straight made the table under Public Schema. Then I altered the table (using graphic interface) and added another text column.

MS Access Autonumber vs. Postgresql Auto Increment

Difference with MS Access is that MS Access assigns autonumber according to sequence by just entering the data into another column. But Postgresql assigns Auto Increment when data of complete row is entered and cursor moves to next row. Since Auto Increment column cannot be null (and is also PRIMARY KEY), so it cannot be blank. Postgresql fills this column when cursor moves to next row (In MS Access linked table). Secondly, in Postgresql, it is possible to explicitly enter any value other than sequence. The same is not the behavior of MS Access. However, explicit entry in this column is to be avoided as it will create problems. For example in fourth row, I explicitly entered number 25. Then next row automatically took the number 4 and it worked up to number 24. Afterwards, auto increment failed for one time and number 26 was entered manually. Then auto increment kept going correctly.

Visible Milky Way Band – It is entire thickness of our galaxy and not just a spiral arm.

Visible milky way band is not a view of just one spiral arm. It is a view of the entire thickness of the galactic disc as viewable from our location within the disc. This band tells us that we are living in a disc shaped galaxy and it also gives hint about our location within the disc.

Suppose you are looking at milky way band in the night sky and start moving towards opposite direction while keep on looking at the band. When you will reach about 2000 light years away from the visible band — from that location Sun and surrounding stars will no more be visible. They would have become a part of the visible galactic band!

Practical Understanding Vs. Intellectual Understanding

Practical understanding of let’s say Newton’s Physics is of the type which is offered by the text books. Students understand the statements of laws along with mathematical depiction thereof and become able to solve numerical or exercise questions. After completing the study in this way, they may become good engineers or professors of physics.

But those who become scientists, they seek understanding of a different kind that may be regarded as intellectual understanding. They not only pursue to understand book contents within the context of daily real life observations, more importantly they also try to investigate the history and logic behind theories of science that they read in text books. Rather than trying to solve text books exercise questions, their efforts are usually focused at finding how the theory in question was actually derived or discovered by the original scientist. The practical understanding makes one able to apply theory in practice whereas the intellectual understanding would make one able to not only improve or refine the existing theories but to propose or formulate new theories as well.

The myth of Cylindrical Universe

In science literature and online sources, the whole universe is often depicted in the shape of a cylinder.

In year 2018, I completed my first book (on the topic of big bang) but a perplexing issue remained outstanding which I could not solve till the publication of the book. The problem was that Friedmann (1922) was saying that Einstein’s depiction of universe was cylindrical whereas Einstein’s own paper (1917) had described universe as spherical.

Following is quote from Friedmann (1922) paper:

In their well-known works on general cosmological questions, Einstein and de-Sitter arrive at two possible types of universe: Einstein obtains the so-called cylindrical world ……..

Whereas if we read Einstein (1917) paper, we find that Einstein was talking about spherical universe:

From our assumption as to the uniformity of distribution of the masses generating the field, it follows that the curvature of the required space must be constant. With this distribution of mass, therefore, the required finite continuum of the x1, x2, x3 with constant x4, will be a spherical space.

Here x1, x2 and x3 are coordinates of three dimensional space and 4th dimension x4 (time) is kept constant and the result is a spherical space.

So the issue remain unresolved till the publication of my book (2018) regarding why did Friedmann (1922) write that Einstein (1917) had obtained a cylindrical universe. However, now I get the clue of this apparent anomaly. It turned out that Friedmann (1922) had taken his understanding of Einstein (1917) from Arthur Eddington’s (1921) book i.e. a secondary source. Following is written in Eddington (1921) book:

It is with some such underlying idea that Einstein’s cylindrical space-time was suggested, since this cannot exist without matter to keep it stretched. Now we freely admit that our assumption of perfect flatness in the remote parts of space was arbitrary …..

Space, Time and Gravitation, An outline of the General Relativity (1921)

Now case is clear before the readers. Einstein (1917) was talking about three dimensional space as spherical while keeping 4th dimension (time) as constant. Eddington (1921) was talking about 4 dimensional space-time to be cylindrical in shape. Friedmann (1922) was talking about three dimensional space and calling it cylindrical on behalf of Einstein.