I created two tables and built a foreign key between them, now I want to reorganize position of the tables in ERD (pgAdmin4 - version 6.14).
I'm try reorganize, but I cannot, see image-01:
My expectation is to align relationship line between tables like in image-02 (ERD MySQL):
Related
So I created a recipe database, and just now I've noticed I forgot to add an ingredient to the second recipe. The order of ingredients is obviously important here, so even if I add it now to the end of the table, it will still be the last when I SELECT the second recipe, when it should be the second ingredient.
Is there any way I can insert it in a specific position, or am I doomed and will have to create an index column specifying the order of the ingredients?
NOTE: This is a junction table, so there's no primary key here, thus I can't insert it using a specific primary key value.
EDIT: Basically I have three tables: Recipe, Ingredient, and RecipeIngredient many-to-many junction table.
Here's the RecipeIngredient junction table structure:
RecipeId: FK
IngredientId: FK
Quantity: REAL
UOM: TEXT
Notes: TEXT
The rules of the First normal form (1NF) are strict on this:
There's no top-to-bottom ordering to the rows.
Meaning there is no way, in a proper database schema, that a record can be "missing at a certain position".
You are indeed "doomed" and
will have to create an index column specifying the order of the ingredients
can you show the table structure?
It is difficult to insert a row in specific position without primary key.
I've been thrown quite the scenario today. Essentially, I have one table (ProjTransPosting) that houses records, and that table relates to a number of similarly structured tables (ProjCostTrans, ProjRevenueTrans, etc). They relate by TransId, but each TransId will relate to only one of the number of child tables (meaning if a TransId of 137 exists in ProjCostTrans, there cannot be a TransId of 137 in ProjRevenueTrans). The schemas of the children tables are identical.
So, my original thought was to create a Map and create the mappings from the various children tables. And then I would use this Map as a datasource in the form so everything can show up in one column. I created all the relationships between the Map and the children table along with the relation to the parent table. I put Map in the form as a datasource and this caused a blank Grid, although I don't know why. Is it the case that the Map object can only by of one table type at any given time? I thought the purpose of this was that it could be universal and act as a buffer to many record types. I'd like to pursue this route as this definitely would achieve what I'm looking for.
In failing this I was forced to arrange my Data Source to perform something like this: SELECT ProjTransPosting LEFT JOIN ProjCostTrans LEFT JOIN ProjRevenueTrans ... The problem with this is, each child table I add-on, it's creating additional columns, and the values of the other columns are all NULL (blank in AX). So I have something like this:
Parent.TransId ChildA.Field ChildB.Field ChildC.Field
1 NULL 1256 NULL
2 1395 NULL NULL
3 NULL 4762 NULL
4 NULL NULL 1256
Normally, the user would deal with the annoyance of having the extra columns show up, but they want to also be able to filter on the fields in all the children tables. My example above, they want to be able to filter "1256" and the results would return TransIds 1 and 4, but obviously since the values in this case are spread out in multiple columns, this cannot be done by the user.
Ideally the Map would "combine" these columns into one and then the user could filter easily on it. Any ideas on how to proceed with this?
Try creating a union query and then a view based on that query.
Maps are supposed to be used only in X++, and not as data sources in forms.
This sounds like the exact purpose of table inheritance in AX 2012.
http://msdn.microsoft.com/en-us/library/gg881053.aspx
When to use:
http://msdn.microsoft.com/en-us/library/gg843731.aspx
EDIT: Adding my comments here to make this a more full answer.
Let's say you have three tables TabPet, TabPetCat, TabPetDog, where TabPet is the supertype table and the others are decedents.
If you insert two records each into TabPetCat and TabPetDog (4 total), they will all have unique recIds. Let's say TabPetCat gets 5637144580 and 5637144581. TabPetDog gets 5637144582, and 5637144583.
If you open TabPet, you will see 5637144580, 5637144581, 5637144582, and 5637144583.
So what you would do is make your table ProjTransPosting the supertype and then ProjCostTrans, ProjRevenueTrans, etc descendant tables. Unless transId is really necessary, you could just get rid of it and only use RecId.
ALTER TABLE a add (OWNER_NAME VARCHAR2,OWNER_PARENT VARCHAR2);
Is it possible to alter table add MULTIPLE columns in a single statement in sqlite3?
The SQLite documentation provides the following picture to illustrate how the ALTER TABLE is understood by SQLite.
So, it does not seem possible to add multiple columns in a single ALTER TABLE command.
Reference: SQLite Query Language: ALTER TABLE
EDIT:
SQLite is a bit rigid when it comes to modifying existing tables and has limited support for the ALTER TABLE query.
Some more information can be found following this link: How do I add or delete columns from an existing table in SQLite.
The link also provides a workaround to carry out complex table modifications.
In a nutshell (emphasis mine):
If you want to make more complex changes in the structure of a table, you will have to recreate the table. You can save existing data to a temporary table, drop the old table, create the new table, then copy the data back in from the temporary table.
I need to manipulate some data in SQLite, it should be simple but trying to figure it out how to do exactly this has frustrated me.
It's just a join, one table called "routes" has a column "stop_id". I need to take another table called "stops" which also has a "stop_id" column and everywhere that they match, add all the additional columns from "stops" to the "routes" table (added columns are "stop_name" "stop_lat" "stop_lon" and "master_station"). "stop_id" is the primary key in the stops table. I need to join the tables and not keep them relational because after I do that I will be changing the rows by hand with new information. I am using Firefox SQLite Manager if that matters.
A join can be done with JOIN:
SELECT * FROM routes JOIN stops USING (stop_id)
However, the result of a join cannot be changed directly; the UPDATE statement works only on actual tables.
To change values that come from the routes or stops tables, you have to update those tables by using their respective primary keys to look up the records.
Database Diagram
I'm trying to create master Info table that has all his fields additionally to other 3 tables. so, the master info table has many phone number, many encoder numbers and many control room numbers. therefore, I have made them in this way but I'm not sure that what if i need to do the opposite, like put the statin_No in each table? instead of putting each table primary key in the masterInfoTable like, putting Audio_keyNo in MasterInfoTable?
the masterInfo table contains(
Station_No, Encoder_make, Encoder_Model, Audio_keyNo, ControlRoom_keyNo, and Encoder_KeyNo)
the AudioTable has(
Audio_KeyNO, Audio_No)
The ControlRoom table and Encoder table have the keyno and control room or encoder no.
any thing end with KeyNO is a primary Key.
You need to create you main station table and other three tables for Encoder, Phone, Control Room. Connect these three tables to the main table you have. So, the main table will have a primary key and three foreign keys for the three tables. This is the best what can i think of from your problem's description. Let me know if you any further question.