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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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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In Oracle, how to get a list with the names of schemas that a user has read permission?

In Oracle, i need list which schemas a particular database user (or the current database user) has read permission. Based on this information, also need to get all the tables and views are in each ...
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100 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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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
44 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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108 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 ...
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30 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 ...
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254 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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45 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 ...
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60 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 ...
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154 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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35 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 ...
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74 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 ...
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243 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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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 ...
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2answers
110 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 ...
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1answer
152 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
60 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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2answers
52 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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39 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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1answer
97 views

MySQL table indexes change location [closed]

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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1answer
48 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
552 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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1answer
39 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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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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21 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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1k 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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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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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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106 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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1answer
32 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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1k views

PostgreSQL: schema diff/patch tool [closed]

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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52 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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30 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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1answer
27 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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63 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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1answer
29 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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3answers
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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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1answer
54 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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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
11k 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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1answer
652 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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2answers
85 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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1answer
1k 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 ...
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CROSS JOIN and updatable model design for Ruby on Rails [duplicate]

I am trying to build the multi-level model in rub on rails to allow the following to happen: When a user creates a campaign they will select some categories and some metros from tables Category and ...
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1answer
333 views

Schema for a reservation system

I'm working on a reservation system schema and have some problems defining availability of resources. I searched for similar question here and on Google but still don't have clear understanding My ...
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1answer
40 views

What are some databases that are schema-full but not relational

What are some databases/datastores that are schema-full, but not relational? In other word I'm after some NoSql databases that are not schema-less. By schema-full I mean that, like in a traditional ...
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255 views

Friendship and Messages in a MySQL table relational schema problem (concerning big data manipulation)

Before you start suggesting this question for duplicate read it, I have searched and i haven't found any proper solution. So, i'm building a social networking site (I know that you are laughing ...