I am currently rebuilding our Intranet and in the process simplifying the database. Currently I have several tables with BLOB objects for resources. I have an Announcements table with photos or files, a user table with a photo and a marketplace item table with photos. In each case the BLOB object has been separated out into another linked table.
Each of these photo/files is stored (historically) in their own table, and as I've migrated them into one system I've begun to wonder if I wouldn't be better off storing all the files and images in an "Assets" table and then referencing that table rather than having three almost identical tables?
Performance is my main concern, but then readability and maintainability is the reason why I'm rebuilding the Intranet.
Related
I'm working on an app that connects to alfresco database.
and I was looking in the tables for the table that contains documents information, and I couldn't find it. I found the table of tasks and other tables.
can anybody help me here?
The two most important tables, IMHO, are alf_node and alf_node_properties. Note, for each node you create you will get a single row in the former, and multiple rows in the latter, depending on the number of metadata associated with your node.
This is because metadata are stored as rows in alf_node_properties with qname_id column holding the information about metadata type.
All files that are stored in Alfresco are stored in what is referred to as the repository. The repository is a logical entity that consists of three important parts:
The physical content files that are uploaded (in {Alfresco_install_dir}/alf_data/contentstore)
The index files created when indexing the uploaded file so it is
searchable
The metadata/properties for the file, which are stored in a
relational database management system (RDBMS).
For more details check Repository concepts
I have shared resources across all of my databases. Users, Companies etc. These are shared between all of my databases and the tables are the same. I want to create on Database for these tables and have all of my databases reference this one instead of having multiple tables that are the same. I come from a C# background and I am not very proficient in SQL. I am writing a new application that uses several of the databases we have.
Question: Should I make one database an authoritative source on these resources? The problem I see is I need Foreign Key relationships between databases and without triggers this is not possible. Not to mention when I write my linq statements I cannot query by these items.
We were able to achieve this by having one central database as the source of truth, then having copies of the applicable tables moved out to all the databases that needed it via triggers. You have to make sure all CRUD is done to the source of truth database, otherwise it gets very complicated to manage everything. You can then create the foreign keys to the copy tables.
I am creating an application in Microsoft Access. This is for a small database that the customer will run on a desktop. No network of any kind will be involved. All the necessary files to use the database must be on a single desktop computer.
I want to deliver the app to my customer in stages. Most likely I will email the .accdb file to the customer. How do I deliver an update and maintain any data already entered by the customer? Updates may include changes to the table structure as well as to forms.
The answers given to my original question address the issue of changing forms and other UI elements. However, what if I want to add a table or add column to an existing one? How do I seamlessly deliver such changes while preserving as much data as possible on the user's end?
Split the database and the interface into separate files. Google should have plenty of information as this is typical for MS Access apps.
Here are a few resources to get you started:
How to manually split a Access database in Microsoft Access
Splitting an Access Database, Step by Step
You absolutely MUST (!) split your database into two parts. A backend part storing the tables ("the database") and a frontend containing the forms, reports, queries and application logic ("the application"). Link the tables from the backend to the fontend.
The frontend might also contain tables with control paramameters, report dictionaries etc., but no data that your customer enters!
Newer versions of Access have a database splitting wizard.
You might need a code that automatically links the backend to the fontend on the customers site.
UPDATE
You have two possibilities to alter the schema of your database on the customers PC.
1) Do the Updates through the DAO (or ADOX) object models. e.g.
Set tdf = db.CreateTableDef("tblNew")
tdf.Fields.Append tdf.CreateField("fieldname", dbText)
...
db.TableDefs.Append tdf
2) Use DDL queries
CREATE TABLE MyNewTable (
ID AUTOINCREMENT,
Textfield TEXT(50),
LongField LONG,
...,
CONSTRAINT PK_MyNewTable PRIMARY KEY (ID)
)
Or
ALTER TABLE SomeExistingTable ADD COLUMN Newcolumn Text(50)
I've bought a CSV United States business database with ~20 million records, which is divided to 51 databases, every database represents a state.
I need to write an ASP.NET MVC Web Application that will query this database, by state and more arguments. Should I create a SQL Server database and import all the records in the all 51 csv files? Or maybe should I query directly to the csv files? What will be fastest? Feel free to suggest and other solutions.
Thanks.
Create a single database, where you put all those records in. But, do it in a structured fashion offcourse.
For instance, you could create a table 'State', and a table called 'Business'. Create a relationship between those 2 tables.
Normalize your database further.
When you want to have a performant database, it starts by defining a good, normalized DB schema.
Add the necessary indexes, and you should be fine.
A database is designed to be able to handle a large amount of records.
One table, with appropriate indexes. 20 million records is peanuts.
I would import the data into one big database. As long as the table is correctly indexed it will offer better performance when querying as instead of having to scan each file it should be able to use the correct indexes to speed things up.
I'm using SQL Server 2008. My database is almost 2GB in size. 90% of it is one table (as per sp_spaceused), that I need don't for most of my work.
I was wondering if it was possible to take this table, and have it backed up in a separate file, allowing me to transfer the important data on a more frequent basis than this one.
My guess is the easiest way to do this is create a new database, create the table there, copy the table contents to the new database, drop the table relationships, drop the table, create a view pointing to the other database and use that view in my applications.
However, I was wondering if you had any pointers to different strategies that I may not be aware of at this point.
Create the table in a different FileGroup.
Here's a link with some good examples.
This creates a second physical file for just that table. It can be placed on a different physical drive for performance. You can do a backup or restore of just specific filegroups, which is what it sounds like you need.
This is one example of the larger topic of "Data Partitioning", which involves various methods of dividing large tables across multiple files.
I suggest the filegroup solution. However to copy a table from a database to another you can do this trick:
SELECT * INTO MyNewDatabase..MyTable FROM MyOldDatabase..MyTable