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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260 views

Review a database schema for a design approval system

I'm working on my first web application that will utilize a database. The basis for the application is a design approval system. I work for a company which mainly produces print and online marketing ...
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1answer
535 views

MySQL DB structure with Main category and several nested sub categories

I am looking to create a set of fields on my webpage identical to what eBay uses on their category selection page when you are selling something. For my purposes I am doing motorcycles, power sports, ...
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3answers
7k views

What is the difference between logical schema and physical schema?

While going through Database architecture I came across Schema's . I am very much confused with: Logical schema Physical schema How these two schema exist in the Database? How can these be ...
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1answer
141 views

Help With MySQL Computed Columns/Auto Updating Field Based On Average

I am currently building a social network type application on-top of MySQL and have run into a problem I can't wrap my head around. In my web application each user has a field called "weight" and this ...
3
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1answer
138 views

Help with “Flexible” vs Fixed Tables

We are designing a database in SQL Server to handle sales commissions. A diagram of the current schema looks like this: There are only a couple of us on the project, and our boss dropped this ...
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224 views

Lossy Decomposition meaning

Suppose I have a relation R=(A,B,C,D) and I decompose it into: R1=(A,B,C) R2=(A,D) then if it is said that the decomposition is lossy,then what is the meaning of that statement?I have an ...
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2answers
127 views

Does this medical database look correct?

I'm pretty new to databases and I'm trying to create some schemas. I've been working away at this one for a while, but I can't help feeling that it doesn't look right. Essentially I have the ...
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1answer
353 views

Can I alter a view being referenced with schemabinding if the change fulfills the binding requirement?

In SQL Server 2008, I have views WITH SCHEMABINDING and I need to alter one. I am changing a column while not changing its alias so consumers will be unaffected. If I were to drop all my other views ...
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59 views

How should I restructure a table that contains multiple columns that contain similar, but not same data?

I currently inherited an InnoDB table that describes a product. In the table there are a few columns that describe the maximum height at which the product may be mounted. These are the columns: ...
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2answers
820 views

Designing database with Category and Tags for Posts - Seeking for guidance/advice

I'm not really a database novice but I'm not an expert either. Problem: I'm having this difficulty on designing my Post, Category and Tags relationship. I've read Normalization many times but could ...
3
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2answers
228 views

Is there a well-known name for this “poor man's ref. integrity” schema design pattern?

Is there a name for the following database schema design/pattern? My eventual goal is to find more literature about the subject. Today's cursory net search was too full of generic words to be able pin ...
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4answers
2k views

eCommerce orders table. Save prices, or use an audit/history table?

Im designing my first eCommerce schema. I've been reading around the subject for a little while, and am a bit confused about the relationship between an order_line_item and a product A product can ...
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2answers
124 views

Schema for lists of relationship differences

Say there is a data model that allows for relationships to be defined either explicitly or as a list of records added or removed relative to some existing item: Item <–> *Properties and Item ...
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0answers
99 views

MySQL Workbench Forward Engineer from only the current diagram

I want to create a test database from a huge schema in MySQL, but when I try to do Forward Engineer from a Diagram with about 6 tables, it try to create all the tables, views and routines groups that ...
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0answers
368 views

MySQL Space efficient way of storing indexed key-value pairs associated with table

We're storing transactions in an accounting system using two tables, one contains the general description of the particular transaction (the other contains the entries, one for each account - which ...
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1answer
151 views

Scheme review/Normalization level/query optimization

So I have a relatively complex database I'm designing - basically full in-house accounting setup. In one section I have some concern that I'm over-normalizing; the 'directory' - I'll example the ...
3
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2answers
55 views

Best design for a many:many relationship issue

We have three types of entity, each with their own table: table:A(a_id), table:B(b_id), table:C(c_id) Each of these entities can have any number of email addresses and linked Twitter accounts. ...
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1answer
164 views

Relation between multiple hierarchical taxonomies linked to a single entity

I am working on an online test application which supports multiple choice questions. I have created schema for taxonomy (classification) system to be used with questions. taxonomy(id, name, slug, ...
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1answer
282 views

Automatically generate ALTER TABLE to syncronize schema on PostgreSQL

i Have 2 different database schema in PostgreSQL sql file from pg_dump, is there automated way to generate alter table commands so it would be in sync, without inspecting one by one? this is the ...
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1answer
217 views

Do I need to explicitly grant permissions for a login under the sysadmin role for it to access a custom schema?

So I have a login that has sysadmin rights on the db server. However, it's not able to access database objects under a custom schema that was created (eg. it cannot select from tables with ...
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1answer
390 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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1answer
430 views

Shopping cart schema with multiple product tables

I have a shopping cart table used to store customer id and product id of their chosen items. However I have multiple product tables, for example cars, books, houses. I started out with one table but ...
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1answer
90 views

Multi tenancy by schema - Deny access to another tenants [closed]

In a multi tenant environment, where the multiple tenants are in the same database and a schema is used to separate each one of them, how can I create a database user (MS SQL SERVER) for each schema, ...
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0answers
100 views

Schema for yearly data models

I am developing a school management system. Most data will not be reused after the end of the school year. I am contemplating using schemas to separate data in various school years, however I am ...
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3answers
469 views

Database design for bookmark system

I am creating a bookmark system where people can save their bookmarks. Each user has its own personal page with bookmarks. A bookmark should have atleast one tag and max five. Each user can create ...
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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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2answers
77 views

Store extra, optional information about any entity [closed]

I've done a bit of reading but haven't found anything related. This must be widely discussed, so it's most likely my fault. I've got a relational database with a number of different tables, each ...
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1answer
463 views

Polymorphic Association - is it bad? [duplicate]

In the following schema: Collections Upvotes Reports Upvotes Reviews Upvotes I'm tempted to have a single Upvotes table with a single "entityId" column that stores either the ...
5
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1answer
1k views

How to migrate between schemas in bulk in SQL Server?

We currently have multiple databases but would like to combine them and, instead, separate our domain contexts using schemas. In MS SQL Server 2008 R2, how can I relocate all the contents of one ...
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2answers
147 views

Accept null value on parent column in multipart relationship

EDIT: I've come up with one poor solution (below) that requires some denormalization, but does avoid the risks of UDFs in CHECK constraints. I would appreciate your help if you have a better answer. ...
2
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1answer
119 views

To normalize or not to normalizde? (10 fields)

I'm helping someone to design a database and for a specific case I'm not sure. I have 10 fields - this will never change - that will always be filled and used in every query that could be coming up. ...
2
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2answers
530 views

How to create a blank version of a PostgreSQL database

I've been using pgAdmin to create a database and test it. I'm at a point now where I need to install this db on different servers. I've been using pg_dump to do this and I've been able to muddle my ...
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2answers
397 views

Postgres sequence usage

I have an Postgres database with two users: dev and junit. Junit and dev objects are dropped and created regularly. They both have the same objects unshared for tables, however, sequences are shared, ...
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1answer
469 views

How To Hide Schema from user

I have DB with 2 schemas: A and B. B schema's procedures use A schema's procedures. I need to create user, which will not be able to see A schema. This user can use only B schema, but i want to let ...
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92 views

Cloning Postgres schema/tables across multiple servers

I'm working on a project that has databases across multiple servers, with one server for each business client. The project has some identical 'base' tables that are present in all the databases (for ...
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1answer
2k views

How to transfer the ownership of the dbo schema in SQL Server 2012

I've accidentally given a user the ownership of the db_owner schema (using the check box in the UI as below) and now I cannot: Transfer ownership to another user Drop the user from DB (though I can ...
1
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2answers
313 views

Oracle - Is it possible to maintain transaction across multiple schemas?

I got this database in oracle which includes 4 schemas. Each schema represents a logical layer. Each transaction (Stored Procedure) in the upper layer breaks into a couple of transactions in the lower ...
1
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1answer
207 views

Should I extract / normalize the mailing address despite requirements limiting number / type of addresses?

I currently am working on a contacts application (similar to Outlook contacts combined with eVites and LinkedIn). The requirements for the application are to limit the addresses (and phone / email ...
0
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1answer
201 views

Data Sync between servers with different schema in SQL Server [closed]

I have two servers 2008 R2 and 2005. The e-commerce site has been running with 2005 Server i has migrated 2005 server data with modified data schema to 2008 R2 from yesterday's date of data. My client ...
2
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3answers
438 views

Many to many link tables with history? [closed]

While creating a PostgreSQL database of customer subscribed services with DNS domains, I want to: enable customers to subscribe to multiple services each service can have multiple domain names per ...
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1answer
223 views

message table schema - body TEXT or varchar [closed]

I want to make a small social network. For messaging body which one is more suitable? VARCHAR or TEXT? if VARCHAR how long is efficient?
0
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1answer
99 views

How to reduce table duplication, while ensuring integrity of the database?

For example, in my app I have some class called Contact: case class Contact(name: String, email: String, phone: String) And several other classes have one-to-many relation to that contact (for ...
1
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2answers
194 views

How can I integrate a new system to a design scheme I previously created?

This is a follow-up to a question I wrote a while ago, for reference, you can look it up here. I've developed a curriculum based database scheme that looks like this(Thanks Joel Brown) Now that a ...
0
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2answers
759 views

Multi-Tenant (SaaS) Database Schema with Sharing

Guys I just need your opinion which is the best approach to design a schema of a database for a SaaS application. I want it all on a single database, At first I think I can simply put a context_id ...
2
votes
2answers
2k views

Import Oracle schema data without losing modifications of stored procedures

I have this scenario: One huge (thousands of tables), complex production database, Oracle 8 One huge (thousands of tables), complex development database, Oracle 9 ( same structure as production ) ...
0
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0answers
26 views

Create a schema like an existing schema [duplicate]

I have a existing schema in my database called SCOTT, how can I create a new schema with exactly the same privileges which SCOTT schema is having? Is there any create like or some command to create ...
0
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3answers
80 views

ER Schema “Optimisation”

I am trying to make an ER Schema for a person. The person will have Current Address and Permanent Address. So far I have it so that both Current and Permanent Address are Composite Attributes and they ...
2
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1answer
99 views

Constrains relationship

I have the following design. Each user has it's own contacts, it's own hosts and assign those to a domain which belongs only to him. I want to insure that the host you assign to the domain belongs ...
0
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2answers
810 views

Which schema is better for a shopping project? [closed]

I'm working on a business-to-customer project that has variety of product types. There are a few properties like name, description, brand_id that each product has but there are also many specialized ...
3
votes
2answers
976 views

DB2 (LUW) equivalent for Oracle “drop user cascade”

This question is related to creating and initialising test and development databases for an application that has the database running on LUW (linux-unix-windows) On oracle, we have an os user (on ...