Consider a database table holding data like that: Id UserId IsCheckIn DateTime Image AccountId 30356 60866 1 2020-12-19 12:17:17 b622f3e0806f.jpg 10017 30355 60866 0 2020-12-19 10:52:26 b622f3e0806f.jpg 10017 30354 60866 1 2020-12-19 10:51:02 b622f3e0806f.jpg 10017 30353 60866 0 2020-01-20 09:29:42 1596.jpg 1…
Tag: database
Why to use NoSQL DB when we could scale out SQL DB by sharing?
I recently read that the NoSQL DB scale out more easily than the traditional SQL DB. But consider that I have a huge table in SQL DB then I could easily distribute rows among multiple servers based on some hash function. For e.g. – If I have 4 servers I could do (id%4) where id is the primary key of
Data Structure for One Entry with Unknown Number of Tags
Noob here. I am trying to create a class or data structure where each entry has one unique name and an unknown number of descriptive tags. I’d like the data structure to be something I could also easily export to some common format (I am guessing that CSV would not be able to do what I am asking since I
Trigger before insert in PostgreSQL and except some columns
I’m trying to write a trigger for my table. This table has 50 columns and 3 of them are timestamp type. In the future I will insert new rows and they can be duplicate of existing, so I need to compute hash of each row. My idea is to compute row’s hash in each insertion and check it’s existin…
ERROR 1452: Cannot add or update a child row: a foreign key constraint fails, Can anybody assist
I was wondering if anybody would be so kind as to try help me figure out th problem with my code. I have an extremially limited knowledge of sql I am a student and this is my first year doing sql. …
How to ORDER BY the amount of a given character in a string using SQL?
The column OTI in traits_general comprises of string values. What I am attempting to do here is to select, in descending order by the amount of zeros in each string, each OTI value. For example: In this instance, if we had the strings, 03001, 22321, 00002, 30203, and 11102, then I would want for it to be orde…
Division of 2 values in mysql
Hello I’m a newbie in SQL. I have a table of workers and I want to calculate the avg num of female workers. I want to divide 2 tables that I create, but when I do the division the value of the new …
How to use a for loop to insert multiple records in a database table
I have simplified my problem into the following code: $sql_abc = “CREATE TABLE $tbl_abc( x INTEGER(255) ) “; echo “About to execute $sql_abc”; if (mysqli_query($conn, $sql_abc)…
When inserting multiple record into a SQL table it does not follow the order
When using a single insert statement to add multiple records into a table as shown below, it does not follow the same order when selecting. I understand that it does not affect anything but may I know …
Designing a database for Large Data and Multiple Users [closed]
I am designing a project that can require thousands of records per Admin(I estimate within a couple years I will see over 100,000 records in the database) and all records are unique to each Admin. (ie …