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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Oracle schema migration to new database with zero downtime

I have a problem: I have two production schemas on one database each serving two different appplicaitons. I need to migrate (move) one schema to an entirely new database that will be dedicated for ...
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96 views

Column type unknown at creation time

I have a table in a MySQL database that stores survey results. CREATE TABLE survey_responses ( response_id INTEGER UNSIGNED AUTO_INCREMENT, survey_id INTEGER UNSIGNED NOT NULL, question_id ...
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6k 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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54 views

Strategies for summary data in parent record based on detail data?

I have parent-child relationship as shown below. I need to find the first order date for each customer. Obviously, writing a query to do this is fairly straight-forward but it does require reading all ...
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544 views

How can a database be normalized when an optional field causes denormalization?

Suppose you have a warehouse full of widgets. Each widget in the warehouse is stored in a specific identifiable location within the warehouse. You might have a schema which looks like this: A ...
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1k views

Candidate key = Key = Minimal Superkey?

I got a little confused by all these keys. As I understand A key of a relational schema = The minimal subset of a superkey that is still a key = A candidate key Is this correct or not?
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91 views

When is it worth it to use Triggers and stored procedures/functions? [closed]

As an example, lets say I have a forum application and for every topic that is created, I have a trigger that fires a database function creating a post.(lets assume we have a topics table and a post ...
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1answer
130 views

Mysql: Schema/Query Performance Approach for aggregated mailbox folders

I am about to code a messaging system where users can write messages to other users. User can create custom inbox folders for sorting the messages they receive, however, every user has 2 main inboxes: ...
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1answer
169 views

What is the meaning of this anomaly warning message?

I have run an analysis with SchemaSpy. The tool gave me a warning message for two tables. The warning message is: Tables with incrementing column names, potentially indicating denormalization ...
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117 views

Many:Many with Shared Relation

I'm modelling data with multiplicity like this: Each Composition/Anthology related pair must share a Composer. Also, each Anthology must contain at least one Composition. How would you recommend I ...
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1answer
195 views

Postgres - Schema information within Trigger?

Background : (Multi-tenant design;separate schema per customer, all table structures identical;Data-warehouse / non-OLTP system here; Postgres 9.2.x). Reviewing patterns for the following problem: I ...
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1answer
2k views

Oracle database created whats next? Create Schema or Create Tablespace?

I'm a programmer that's being thrown to the DBA/Sysadmin island all by myself with a volleyball that I named Wilson. I'm trying to survive here. I'm supposed to create a database for an application. ...
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254 views

XML Data convert to SQL database,

I have an XML feed that i need to parse daily, i want to store all of the data from the XML feed in a SQL table so then that data can be queried and manipulated by my clients. I can currently parse ...
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2answers
194 views

PostgreSQL and default Schemas

Whenever I create a brand new database in PostgreSQL Maestro it creates the following list of default schemas: Now from my understanding Schemas are like folders for organization, etc. So the ...
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78 views

In regards to GS1 barcode - what size DB field are used?

In regards to GS1 barcode - what size DB field is used or is the entire GS1 typically not stored in database, but rather processed in the application layer and stored in the database as a collection ...
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1answer
262 views

Database schema design help needed

I am developing a PHP application expecting millions of records both parent and children. My goal is to design an optimized database design to achieve high speed and performance. This application ...
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3answers
32k views

How do I list all schemas in PostgreSQL?

When using PostgreSQL v9.1, how do I list all of the schemas using SQL? I was expecting something along the lines of: SELECT something FROM pg_blah;
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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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39 views

Modify legacy table schemas that have no primary key

I've been tasked with updating our database (SQL Server 2008) so that every table in it has a proper primary key defined. Due to various reasons over the years we have somehow built up some legacy ...
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510 views

How to represent class table inheritance (current DBMS-specific way please)?

I want to implement class either-or table inheritance (Account, CatAccountDetails, DogAccountDetails) in SQL Server. I found a recommendation for MySQL here (How do I map an IS-A relationship into a ...
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1answer
636 views

Compare two MySQL dump files

I am trying to compare two MySQL dump files. One was made from a fresh install of a web application and the other is a dump from the same web application that has been upgraded from a previous version ...
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1answer
657 views

Will table inheritance in PostgreSql suit this situation?

Let's start off by saying, I'm new to PSQL and coming from a MSSQL background. I'm starting to design a DB in PSQL. So my main aim is to have a Main schema in this DB, which I am going to use to ...
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3answers
24k views

Difference between database vs user vs schema

I'm really confused with the terms database, user and schema. Can anyone explain how they are different from each other (if they are)? If they are same then, what are the similarities between them? ...
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1answer
45 views

Multiligual database design

I assume that the best approach for many languages (5 and more) is concept based on: CREATE TABLE `language` ( `language_id` char(2) NOT NULL, `collation` varchar(64) NOT NULL, ...
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2answers
209 views

Extensible Asset Database Schema

Background I work for a decent sized company in the hardware sector. Currently, we have a number of varying assets that need to be tracked. Until recently, this was done by hand as was an ...
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1answer
2k views

Granting permissions only on a set list of objects

I have a SQL Server 2005 database with a large number of tables in the dbo schema. I now created a new schema (call it myschema) that only has three table-valued functions and two stored procedures in ...
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2answers
62 views

Best practice for database where the values can't change

Suppose I have a table Inspection with a field for Place (the location where the Inspection occurred). The field is a foreign key to a Place table, where each place has a Name, among other things. The ...
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MS Access ER diagram

I have database scheme for Microsoft Access. I'm interested how I can convert the scheme into an ER diagram? Is there any tool that can do this based on scheme relations?
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Database Design - different objects with shared tagging

My background is more in web programming rather than database administration, so please correct me if I'm using the wrong terminology here. I'm trying to figure out the best way to design the ...
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1answer
3k views

Difference between Owned Schemas and Role Membership for Microsoft SQL Server

Are there differences between Owned Schemas and Role Members? From my understanding, the Role Members are compulsory - user need to have at least one of the check box under Role Members checked. ...
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2answers
2k views

SQL Server - backup / restore schema only (not a duplicate if that's what you're thinking!)

We have a DB on over 100 servers of which we want to backup / restore the structure of just 1 at a time to a specific UAT database. They're all called the same thing but vary in terms of schema - ...
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1answer
119 views

Tools and methodologies to keep to DBs aligned [closed]

2 DBs having schemas that represent the same semantic objects. The first one is production DB (Non-RDBMS, in-house implemented in-memory DB with shitload of RAM). Other is Postgres. Once in a while ...
2
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2answers
291 views

How to design future proof tables?

I am new to database design and have started developing my first schema. Some of my tables (e.g. user_profile) I am struggling to come up with an exhaustive list of fields for the table. A particular ...
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2answers
539 views

Restore SQL Server database from .sql files

So we had an encrypted database that puked and killed our whole SQL Server setup. Sucks about our data, but we were smart enough to have our data structures / stored procedures / functions in Git The ...
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Examples of a database with no consistency measures that ensures consistency through schema alone

To clarify, the database can be any type RDBMS, NoSQL/BigTable. However, it must not employ any usual consistency measures such as locks, or synchronization, but the inconsistency-invincibility must ...
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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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2answers
108 views

Relationship that are optionally more specific

Forgive my title, I couldn't think of anything that accurately describes what I'm talking about. I currently have the following relationship. CREATE TABLE Events ( ID INT IDENTITY(1,1) NOT ...
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75 views

What to have in the main table and what to have in meta_table?

I'm try to figure out the best scheme for the users table for my software. I'm trying to separate the main data and auxiliary data into 2 table called users and user_meta for the sake of extensibility ...
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2answers
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how to add trigger in mysql workbench, without UDF, using EER design

I have designed a simple database using EER in workbench. However, i want to have a minimum value for the attribute salary (compared with min_value attribute from artist table). Here is the schema: ...
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2answers
1k views

Billing Module (Fee) for School Management System

I am working on a School Management software which includes module for billing of students i.e, fee collection from students. The fee is collected on monthly basis (12 times a year) and the total ...
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2answers
347 views

Relationships in a school database

I am designing database for a school app. Student is the main entity in the database. Student has relation with Parent & Guardian. I am confused as where to store references. As will student ...
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2answers
456 views

Data warehouse support tickets

I'm starting to design a data warehouse for a company. The first questions we're trying to resolve are regarding their support ticketing system. My initial schema is as follows Now one of the ...
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2answers
503 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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2answers
290 views

Schema design for privacy settings in MongoDB

I have a set of documents that can have various privacy settings around them: They can be completed public (any registered user) can view them They can be viewable only by people following you (this ...
3
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1answer
131 views

Optimised Schema for City-to-City Distance Table

This is my first question, forgive me if this question is simple. I'm stuck here, trying to implement the relations for the data represented below. I want to scale it vertically (new rows), instead of ...
5
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1answer
900 views

How does Postgres 9.2's streaming replication handle schema changes, and initial table setup?

I want to set up a backup database on the physical server which sits right under my primary physical database server. I'm using Postgres 9.2, and I want to use synchronous, streaming replication (for ...
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0answers
291 views

Powershell to dump database schema to text file

I want to be able to dump a database schema to a sql text file using Powershell. I want this because our DBAs want to be able to do a diff on the file that is committed to SVN. They won't execute it ...
2
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1answer
127 views

how to deal with foreign keys with fixed values (on a db-table-basis)

I have a control table that looks like this: CREATE TABLE `tbl_control` ( `tm_db_tbl` varchar(64) NOT NULL, `tm_key` int(11) unsigned NOT NULL, /* a bunch of other fields here */ PRIMARY KEY ...
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2answers
201 views

How many fields is too much for a primary key?

I am creating a table to store information about the placement of objects in a grid (game map). For example, I have a 10x10 grid and I want to store, in the database, that cell (5,5) has a blue box, ...
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1answer
46 views

viewing Original Object under synonyms

I have certain synonyms in my schema which represent views from another schema. Now in oracle sqldeveloper, I am unable to see the actual SQL for those views but I see only an SQL like: CREATE OR ...