A schema of a database system is its structure described in a formal language supported by the database management system (DBMS) and refers to the organization of data to create a blueprint of how a database will be constructed (divided into database tables).

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How to differentiate between class and attribute

I have this problem: Library has books, VDOs, CDs Journals. It gives loan to users. Books and Journals can be referential which cannot be loaned out more than 2hrs and non-referential which can be ...
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51 views

Tuple Relational Calculus help? [closed]

I have the following three questions in relation to the following diagram: 1) How many copies of the book titled “The Lost Tribe” are owned by the library branch whose name is "Sharpstown"? ...
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1answer
49 views

Why wouldn't I put the single preferred option into its own table, instead of having a 'Preferred' column?

In similar spirit to How to implement a 'default' flag that can only be set on a single row I would like to specify that, for any given list of possible names for a business, only one of the ...
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1answer
363 views

Is an ER diagram an example of a conceptual, logical or physical schema?

I have been reading databases, and I clearly understand the difference between a conceptual, logical and physical schema. An ER diagram is an example of which of these schema's?
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4answers
196 views

How can I compare the schema of two databases?

Is there a way to find the differences in two SQL Server databases (schema only). One is local and the second is at a customers site. We are experiencing problems with crystal reports running some ...
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6answers
13k views

Is there any good tool for making Database Design and Prototypes? [closed]

I would like to have a good tool for designing the Database Schema with all the tables, columns, data types and relations. Today I mostly do this with pen and paper but I would like to do it in a good ...
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1answer
676 views

Select rows from table where each row refers to a different schema

I have customer table in public schema. And I have a schema named after each customer. Each customer schema contains different tables like portals, plugin, ... When I want to select portals used by ...
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2answers
177 views

Is EAV an appropriate design for a collection of coexisting metadata-rich “fact estimates” on objects? [closed]

I'm attempting to architect a system that will collect estimates on various quantities (10+) on each of many (300K+) objects, and make decisions from the historical record of these estimates. For ...
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0answers
20 views

Schemas with the same name in a Redshift cluster?

Is it harmful in some way to have multiple schemas with the same name in a database cluster, specifically Redshift? I want to create multiple databases, and then create a schema "tables" or "data" or ...
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0answers
8 views

How to handle private local databases in a multiDB cloud environment

In context of Platform as a Service (PaaS), we would like to offer our clients a private platform. A platform includes a website and a database. A platform is not 100% separated. Users could "travel" ...
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0answers
12 views

CLR UDT SCH-M blocking

I’m hoping someone can provide some guidance on a problem I’m having with schema locking on C# CLR UDT’s. I’ve been on the Internet for an extended period of time researching my problem without ...
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245 views

Railway Reservation System [Miniature] Schema

I am working on designing a schema to support the development of a miniature railway reservation system, using oracle 11g XE. This is for a project purpose, I am need to be sure about the correctness ...
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1answer
328 views

Use a set database schema or EAV design? [duplicate]

I have already created a database design with a set schema. The database schema is for a web quotation form. PS it is not a simple quotation form and hence need to customise the form, form builders ...
4
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2answers
738 views

noSQL ACID and consistency for banking

We are building a real time banking platform and app. Our prime concern is safety and consistency of our data across multiple db servers. We need transactions and we can't afford to risk power ...
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0answers
44 views

Mongodb schema design validation

I am building an app which allows users to do some "tasks" to earn points. The "tasks" are part of a "campaign" which themselves are a part of "brands". I am confused about the schema for storing the ...
2
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1answer
138 views

How to efficiently create a new PRIMARY KEY CLUSTERED definition online

Given a table with a PRIMARY KEY definition (acting as the clustered index), I want to efficiently change the definition of the PRIMARY KEY (or at a minimum, just the clustered index) online. I would ...
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2answers
25 views

Can we determine FDs if we are given some tuples?

I am taking a databases course and i'm learning about functional dependencies. I have searched around and did not find any information on this. My questions is if we are given a table with some ...
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1answer
269 views

Not able to solve issue: Incorrect string value: '\xC5\xABt\xC4\x97'

I am facing database error Incorrect string value: '\xC5\xABt\xC4\x97'. I did a lot search and tries a few ways, include move from utf8 to utf8mb4. But still not able to solve it. Following are the ...
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3answers
1k views

Is it bad idea to create foreign keys on the tables in a different schemas in the same database for big applications?

I am working on the transfer a big pl/sql web-based application to the dedicated server. This application is located in one schema with 70 packages of programm code. This application was made ...
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0answers
54 views

The MondoDB.org “Category Hierarchy” Example

I am creating an MVP app for a client but I am skilled in iOS mainly with only some DB experience. I'm using MongoDB. The schema is for a Product Catalog for small markets. The client wants a ...
2
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1answer
514 views

Should I save “document ID” as a String or Number in MongoDB

So I'm importing about a 100,000 documents into mondoDB. MongoDB already generates an Object hash but the data has a documentID that was used to identify records in the previous database. The IDs ...
0
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2answers
39 views

Is it a good idea to add a reserved field to a large MySQL table?

As you may know adding a new column to a MySQL table with millions of records is hard and in some cases impossible. Is it a good idea to add a text column to each table (say, meta) to save some ...
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1answer
441 views

Is there any way MySQL can list relationship cardinality between two entities?

I am working on the project where I have to analyse the MySQL schema. As a part of schema information, I want to list down relationship cardinality between different relations. Does MySQL stores ...
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0answers
15 views

database structure for an object of keywords

Each object I am storing is made up of a title, a description and 10-20 keywords. Each keyword is grouped and some groups can only have one member keyword assigned to an object. Objects will only ...
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1answer
140 views

Dropped connections, corrupted schema … is MySQL sick?

Lot's of problems and I wonder if it's all tracable to some root cause. I'm trying to load a simple schema related to product marketing. The symptoms are: Not being able to forward engineer said ...
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21 views

How to model role and different activities

I am new in the database design and I'm facing this problem, I hope somebody can help me. In my domain we have 3 roles, Non-Supervisor, Supervisor, Manager. I created a Person table and a role table ...
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2answers
859 views

Backup Only Database Schema Everynight

I have an instance with 15 databases on SQL Server 2012. I will set up to backup system which will work every night. I want to backup only the schema because several databases are very big. I haven't ...
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56 views

what is better, multiple column or multiple rows while schema design

I would like to know, which is best in fast retrieval and reporting as numbers of records will increase with time. So lower the record better would be the performance. Priority would be fast response ...
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1answer
220 views

How does Amazon create the RDS for Postgres? Some kind of Docker?

I am really curious about the infrastructure of Amazon. When I create a new instance of RDS, it gives me a host, username, password.. Everything. Behind the curtains, how do they do this? It´s some ...
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3answers
5k views

database schema design for school system

I am trying to create a database to store information about a school. I need to store each department in the school. Each department then has a list of teachers. Each teacher has a list of classes ...
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0answers
34 views

Percona and MariaDB-10.0 ignoring not null on table fields

On the percona-5.6 and MariaDB-10.0 servers, the NOT NULL declared on table field are being ignored. I am able to leave fields declared as NOT NULL empty when inserting data and the servers are not ...
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1answer
116 views

Convert multiple databases into schemas SQL Server

Due to a high amount of databases being created on my project and the rising cost per databases I had the following question: Is there a way to convert multiple databases in SQL Server into one ...
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1answer
440 views

Insert rows in a table, via a row-level trigger, activated after insertion in that same table

I have to design a schema and trigger system in SQL that will save words and their synonyms. I thought of this basic schema: create table words ( id int primary key auto_increment, word ...
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43 views

In terms of relational databases is a Relvar the equivalent to a Schema?

I've been reading up on relational databases and the term Relvar and schema keeps coming up. From my understanding: A relvar is a variable holding a relation. A schema is a logical definition of a ...
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1answer
118 views

Schemas and user permissions

When our custom, home-grown CMS creates data tables using the GUI, it creates them against the site-specific user schema (i.e. sitename) instead of the dbo schema. The issue is that our ...
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5answers
6k views

Is there a name for this database structure?

Noob question, sorry if it's too basic for this exchange. We process a routine data feed from a client who just refactored their database from a form that seems familiar (one row per entity, one ...
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1answer
47 views

Need Help in building database

I am developing an app that send messages (email and sms) to users. The db must also maintains the list of messages send to users. And also the status of messages send to user like send or failed. I ...
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1answer
114 views

Is there a performance hit by breaking out tables into different schemas in SQL Server?

Is there any kind of performance hit when querying by placing tables in different schemas in SQL Server. For instance if I had 2 tables, Table1 and Table2, and put Table1 into the test schema and ...
0
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1answer
33 views

Design for periodic data cuts

I've been building an application that has a 6-monthly update schedule, i.e. a cut of the data for H1 & H2 of each year. The previous version of this application implemented this by making a copy ...
0
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1answer
392 views

Migrating everything to do with a schema from one Oracle DB server to another

We have an old DB server, running Oracle 11g on Solaris. We also have a new DB server, also running Oracle 11g, but on RHEL. We want to move a schema to the new db - but we need everything it refers ...
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1answer
50 views

Schema copy from 9.5 V to 10.5

Using DB2 move utility db2move to copy schema and database from source to target server. The source server is Server1. The target server is Server2. Do I need to set up the TCP/IP port ...
2
votes
0answers
74 views

Schema for user drag and drop ordering

I'm trying to work out the schema for a system where users will be able to order items in an (unlimited length) list by drag and drop. Is there any kind of standard way of storing this ordering ...
0
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0answers
230 views

LCK_M_SCH_M Blocking

I have 2 stored procedures (one vendor, one third party) that are constantly (monthly) stepping on each other. They both (for some reason) acquire a schema lock when all they are doing is updating ...
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0answers
38 views

Accounting - Dimention table in mysql

I am designing a accounting and mini erp system. I use a date dimension table to track all date related data. In oracle we can have many schema for a database. so we could create each schema for ...
0
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1answer
79 views

ALTER TABLE blocking in MySQL 5.6

I have a question with a MySQL 5.6 master-slave setup. If I were to modify the master's schema with an ALTER TABLE SQL query, then when the slave tries to execute that ALTER TABLE statement too, would ...
1
vote
1answer
288 views

Database Design for NoSQL Fantasy Baseball League

I am trying to create a proper schema to place scraped data into, using a MongoDB database. Currently it looks like Team { id : id, name : String, teamLink : String, username : ...
2
votes
0answers
71 views

Proper design of routes in Database MySQL

I'am trying to find out the best database design and try to stick with data integrity by using Foreign Keys. But I'm stuck right at the beginning because of limit relations between tables with FK to ...
0
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2answers
162 views

Is there a way to replicate certain part of collection in Mongodb

Is there away to stream certain part of collection in MongoDB or TokuMX from master server to another server? I need to duplicate only certain collection Or if it isn't possible, are there any other ...
1
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1answer
221 views

PostgeSQL 9.3: What is the difference between text and pg_catalog.text?

I have a classic 3-environments setting (dev, staging and production), each with its own RDS PostgreSQL 9.3. The client/server versions are psql (9.3.5, server 9.3.3). In order to keep the schemas ...
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1answer
78 views

can I give permission to insert into view, but not to referred table?

Here I have a view in public schema referring to the table in private schema: CREATE OR REPLACE VIEW public.products AS SELECT products.id, products.product_id, products.title, products.company_id ...