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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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 ...
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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 ...
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28 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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Stock table Database Design [on hold]

I have to design a stock database of various products for different entities i.e. Distributor, Manager, Field Force. The Distributor allocates some products from his stock to manager and manager ...
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21 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 ...
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9 views

In MySQL 5.6, schema changes in master blocks the slave?

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

Can I update only the needed changes in a database?

First of all, I apologize if you can't understand very well what I am saying and it can be edit for better understanding of my post. The next example is for better understanding of databases with ...
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27 views

Schema/Structure to handle secondary computed data

I'm trying to design a LAMP-based website for my pinball league, which plays competitive pinball every week in match play. One of the features of our league is that we convert raw scores to ...
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19 views

MySQL table indexes change location

Is it possible to move the MySQL Table indexes to another location rather than "datadir" ? for example a ssd drive or memory partition ?
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30 views

How can prevent writes to a Postgres schema for a period of time?

I am moving a schema from one server to another using pg_dump + pg_restore + drop schema cascade. I need to know that no applications are writing to it (or at least that the writes will fail) during ...
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1answer
405 views

How to normalize my db schema for a quiz application?

I am putting together a quiz application. (I'm calling each quiz a "challenge") I have a "challenge" table and a "challenge_question" table which is pretty straightforward. challenge table: id ...
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125 views

Duplicate Relationships in Rails/MySQL Healthcare Application

Overview of the Application I am building a Ruby on Rails application to organize medications, using MySQL. The goal of this application is to provide dosage specific treatment recommendations, and ...
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1answer
247 views

Best embed/reference/field strategy for many inserts (mongo)

I'm building a gaming backend with Mongo, and have some issues on how to best design the schema to maximize performance and database size. My models: User Match -ReferenceMany (User) ...
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44 views

copy data from public schema to another schema in postgresql

I'm creating a multi-tenant RoR app using PostgreSQL 9.3.5 running on linux (Ubuntu 14). I'd like to copy the data from my public schema to another schema. I tried: pg_dump -U my_username -h ...
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1k views

Oracle schema import is not importing all the tables present in the schema dump file

I have exported an existing oracle schema from another machine and then imported it in my local machine. Import was successful, but some tables which are present in the export dump file are not ...
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190 views

DB2 - how to safely blow away database on linux?

I'm using (I believe) 10.1.2, on CentOS 6.5 (for sure). The underlying problem I have is that the database upgrade package prepared in house isn't working for me, in at least the sense that the ...
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23 views

Simplest way to log in as Oracle user different from schema user and still see all tables,… of schema?

What is the simplest way to log in as user X and see all tables,... of schema Y as if they belonged to X? With an Oracle 11g database, I would like to log into the database using user X but all the ...
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2answers
182 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 ...
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114 views

How to store immutable, unique, ordered, lists?

I have an entity with millions of instances. Each instance has to reference an ordered list of items. The lists have to be unique so no list will be stored more than once. But once created, both lists ...
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13 views

How to store external IDs from different sources?

I have a table of customers with a PK that we can use as an identifier for our internal system. These customers may belong to different companies, each of which may have an external ID in some ...
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1answer
28 views

SQL Server 2012 how to create new schema from existing database selecting only subset of database objects?

I'm looking for a way to create new schema from existing database selecting only subset of database objects. I.e. I want to have some "database representation" which only includes subset of tables ...
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4answers
3k views

PostgreSQL: Creation date of a table

I've recently finished a project, during which many DB tables were created. Most of these tables contain temporary garbage, and I am looking for a simple way to list all these tables. Is there a ...
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1answer
764 views

What's a good way to model user authorization to hierarchical data?

I'm wanting to implement something that's basically an ACL in SQL Server (2008, we'll be moving to 2012). We're working with farm production information. We will have users who need to be authorized ...
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119 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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11k views

Copy complete structure of a table

Using some methods, when you create a copy of a table you lose indexes, PK, FK, etc. For example in SQL Server I can say: select * into dbo.table2 from dbo.table1; This is just a simple copy of the ...
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42 views

Composite Foreign key to single primary key [duplicate]

How do I create a composite foreign key to a table with a single primary key? For example suppose I have the following tables: CREATE TABLE Branches ( BranchId UniqueIdentifier DEFAULT ...
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23 views

Re-posting schema

I'm building a social network very similar to Twitter, in which users can see a feed with content posted by users they follow. Users can like and re-post (i.e. "Retweet") posts. Re-posted content ...
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243 views

PostgreSQL: schema diff/patch tool

Consider the following setting: A production DB A dev db, on which schema changes are made to enable new features When the development of a new feature is complete, I have to manually update the ...
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1answer
697 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 ...
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37 views

How to determine a schema version at runtime

Is there a portable way or best practice to access a version number for a schema at runtime? Rationale: you have multiple systems (development, QA, etc.) where you push schema changes from one system ...
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71 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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29 views

Rescue truncated data from incorrect column type

I have mistakenly inserted a variable 18-20 digit variable into an unsigned INT() column. The data has been truncated to the max 32bit length so all my data is displayed as "4294967295" Is there ...
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21 views

Postgres: modify existing search_path (preserve current values)

Sometimes I would like to extend the existing search path, rather than replace it, say: To start with say it is already set like so: SET search_path TO schema_b, schema_c, public; I want to add my ...
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150 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 : ...
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370 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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21 views

Which foreign keys do I use if they are repeated

I have the following two tables company_relationships |ID|Company_ID|Affiliate_ID|<Relationship Info>| +--+----------+------------+-------------------+ jobs |ID|Company_ID|<Job Info>| ...
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25 views

Entity Schema Design

I'm working on an application that has an "entities" system (built before my time) that models users, customers, contractors, vendors, etc. These are all types of people, but have different needs in ...
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18 views

Working out validity of table relationship

Question Background: In a quest to improve my skill set with TSQL programming I'm designing a 'simple' database schema for a zoo. In all I currently have 4 tables but am having an issue working out ...
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341 views

Designing Simple Schema for Disaggregation of Demand Forecast

I am doing a simple database design task as a training exercise where I have to come up with a basic schema design for the following case: I have a parent-child hierarchy of products (example, Raw ...
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3answers
4k 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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How to store highly configurable relationships based on multiple conditions

I'm trying to devise a schema that needs to be extremely configurable when necessary, but also minimal wherever possible. There is a large number of condition types that would lead to a number of ...
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101 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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1answer
39 views

to pivot or not to pivot - schema design question [closed]

I am implementing something similar to this schema http://www.databaseanswers.org/data_models/event_reservations/index.htm It occurs to me that the pivot table for Customer_Bookings would just keep ...
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1answer
28 views

Ensuring that 1 row has 5 specific records referencing it

Context: a TEST has many CASEs. Typical. However, the catch is that a TEST instance must have exactly 5 instances of CASE (1 to 5). I could do something like this: create table TEST ( ID ...
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18 views

Database & Structure for SaaS reporting software

I'm building a SaaS application to allow users to upload data and perform reporting and analytics on it. The reporting and analytics would be quite simple like grouping and aggregating. This has ...
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1answer
7k views

How can extract the table schema from just the .frm file?

I have extracted the data directory of mysql from a backup and need to get the schema from an old table, however it's a backup from a different machine. I have read a fair number of tutorials today ...
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2answers
46 views

PostgreSQL : dependencies on a schema

I need to delete a schema in my PostgreSQL database. I would like to make sure that the schema is not used in another schema (for instance : this schema is used for a view in another one). Is there a ...
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1answer
96 views

Updating mysql trigger via information_schema — access denied?

I have some wrong "definer"s for some triggers in MySQL (actually MariaDB). I figured the easiest way of correcting them would be some version of: use information_schema; update triggers set ...
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74 views

Unique column values between tables

I'm keeping track of teams and their members. Each team has one leader, one contact person, and any number of players, and each of them has a unique email address. The problem is that one physical ...
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65 views

PostgreSQL complaining about shared memory, but shared memory seems to be OK

I've been performing kind of intensive schema dropping and creating over a PostgreSQL server, but now complains..: WARNING: out of shared memory ERROR: out of shared memory HINT: You might need to ...