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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MySQL schema for recurring events - Query by specific date

I've just asked this exact same question on stackoverflow so apologies for cross posting but I only just noticed dba so thought I'd ask across here as well. I'm just about to start putting together a ...
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18 views

Delete all types created by a user

In Oracle 10g, how do I delete all the types owned by a specific user? This is the view that gives me the types I want to drop:SELECT type_name FROM user_types;
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1answer
25 views

one to zero or one relation strategy

For a 1 - > 0..1 relationship (Let's say a product can have none or 1 product_price) What are the differences between this 2 scenarios. When one should be encoraged over the other or is anyone bad ...
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30 views

mongodb Date strings and other issues

I asked a question on Stackoverflow, and was told that my schema was way off. I am using mongodb to store whether or not a log file exists. The log file contains info for an hour. I'm not actually ...
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40 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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1answer
53 views

Saving passport information [closed]

For starters: Our company is based in Germany and thus is based on German law. Germany now has adopted a new act regarding anti-money laundering and which information needs to be stored. Now we're ...
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26 views

Need help with data model

Schema does not list all fields, but only the relevant ones User adds credits/funds to his account using paypal or Internet Banking (which has to be verified manually, and approved, so the 'status' ...
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1answer
44 views

understanding (and modelling) grocery shopping lists

I am having a hard time understanding how multiple product orders are mapped out. What is the best way of modelling a shopping list for multiple customers? I am developing an C# application that ...
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16 views

IBM DB2 9.7 determining default tablespace

I have a DB2 9.7 database. I have defined any specific tablespace, so all tables go to USERSPACE1. Now I have created two new tablespaces and assign two tables to each of the two new tablespaces with ...
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2answers
71 views

Postgresql: Query across schemas

I have multiple schemas that I need to query across. The schemas are not know in advance for example: U111 U222 U333 I need to select across these three schemas from a specific table in each of ...
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1answer
98 views

Searching 500 million records of binary data

I will inserting into a database the signatures of 500,000,000 pictures. The signatures will be generated using libpuzzle. Each signature is 338 bytes. (so 160 GB) plus a table for searching (read ...
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46 views

Do supertables produce bottlenecks?

There are several alternatives to using polymorphic associations and one of them is to use the so-called "concrete supertable". From my point of view, this is the neatest solution and is pretty easy ...
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1answer
42 views

How can I Automate MongoDB schema design from existing MySQL Database and Logs?

I am working on the project which will automatically generate sample MongoDB schema analyzing existing MySQL database and logs. I am looking for help regarding the below questions. Please, share your ...
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28 views

Multi language where this feature never existed

I need to implement multi language system in an existing system that was not developed for this. The number of entries in the tables that will hold data that has to be translated will not exceed 5 ...
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1answer
41 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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2answers
75 views

Dynamically change schema to accommodate custom fields!

I am working on building a sort of a cms for a particular project. Nothing that will have a large volume of records in any table. Within 6 digits max. I was thinking to create the default schema for ...
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1answer
53 views

MySQL 5.5 to 5.6 Upgrade. Will data remain the same?

We are considering to upgrade to MySQL 5.6 this summer. I would like to know if our data will be changed in any way once we perform the upgrade? I've been reading and I found that mysql_upgrade ...
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0answers
83 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
43 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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43 views

Mysql profiler different duration information_schema.profiling

Hi! I have a problem and no idea how to resolve it. I'm trying to use mysql profiler. I'm using the command: set profiling=1; to turn it on. Later, i execute my query which is correlated ...
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2answers
196 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
57 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 ...
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30 views

Unique database presentation ideas

I have completed the first phase of a fairly large database schema design. I built the ER-diagram in DIA. I have to present the schema to an audience of fellow software engineers. Any thoughts on ...
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1answer
60 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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19 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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1answer
60 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
56 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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21 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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1answer
45 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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2answers
196 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
298 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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1answer
45 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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18 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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43 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
96 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 ...
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2answers
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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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32 views

Schema & Database Role Permissions Issue

I have a Schema and a Database Role. An Active Directory member is added to the Database Role. I grant the Role Select permission on the Schema. Control permission is denied on this Schema. However, ...
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11 views

Reducing schema to shrink real-world data to a functional subset

I work with two editions of a shipping product; call them "A" and "B". Both use similar a database schema, but edition "B" has a strict super-set of the schema (and features) used for edition "A". ...
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1answer
74 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
93 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
58 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
75 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
146 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
57 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
29 views

Should I be worried about duplicate entries in the Oracle all_dependencies table?

I think there are some problems with object relational functionality in Oracle 11g (and some earlier versions). We have a purely relational mapping ready as it is easier to handle, but need to support ...
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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 ...
2
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3answers
125 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 ...
4
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2answers
159 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
46 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
83 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 ...