centralized database advantages and disadvantages

relational databaseAdvantage:1. Good at handling small data volumes2. Good at complex SQL operations, can make complex queries such as joins3. Can easily generate a variety of data objects, the use of stored data to build forms and reports, the visibility of goodDisadvantage:1. It is difficult to write processing for distributed applications and large amounts of data2. Indexing and structural changes to tables with data updates3. Application with Field not fixed4. Handling of Quick return result

Tags: language keyword trigger copy table market share form beauty of memory data electronics1 Requirements What are some of the database management Systems (DBMS) on the market today, and what are their characteristics? What are the advantages and disadvantages between them? What are their use cases, respectively? 1.1 What kind of

performance;2, fixed table structure;3, high concurrent reading and writing needs;4. High-efficiency reading and writing of massive data;Non-relational databaseMongoDb, Redis, HBase1, using key value to store data;2, distributed;3, generally do not support acid characteristics;4, non-relational database is strictly not a database, it should be a data structure of the collection of storage methods.1, withou

Original article translated from: Simplified. If the database can run continuously, of course, it is best. However, this is often costly. Sometimes it is even more advantageous than what it gets. In the sqlserver2008 database, there are many high availability solutions. For example, you can use failover clusters, database images, log transmission, replication,

Why create an index? This is because creating an index can greatly improve the system performance. First, you can create a unique index to ensure the uniqueness of each row of data in the database table. Second, it can greatly speed up data retrieval, which is also the main reason for creating an index. Third, it can accelerate the connection between tables, especially in achieving Data Reference integrity. Fourth, when you use grouping and sorting cl

without worrying about its stability;MySQL offers a wide variety of different user interfaces, including command-line client operations, Web browsers, and a variety of programming language interfaces, such as c+,perl,java,php, and Python. You can use a pre-packaged client, or simply write a suitable application yourself. MySQL can be used for unix,windows, as well as OS/2 platforms, so it can be used on personal computers or servers;Disadvantages:Hot backup is not supported;The biggest drawback

1, compared with relational database, the advantages of MongoDB:① Weak consistency (eventually consistent), to ensure the user's access speed② document structure for easier access to dataThe ③ built-in GRIDFS supports high-capacity storage.④ built-in sharding.⑤ third-party support is plentiful. (This is the advantage of MongoDB compared to other NoSQL)⑥ Superior Performance2, compared with relational

Introduction: DB2 9 databaseIt is an important development in the development history of DB2 databases, but DB2 9 databases are not perfect, so there are both good and bad aspects, the following describes the advantages and disadvantages of the DB2 9 database. Compared with other database management systems, DB2 9 has

The advantages and disadvantages of Oracle Database indexes are mdash, mdash, and learning notes. The main advantage is convenient query and improved system performance. By creating a unique index, you can ensure that the database The advantages and

Comparative advantages and disadvantages of several database connection methods Access interface Ease of Use Operational capability Scalability Technical level Outstanding Features Odbc Poor Higher Poor Underlying Lower level control possible MFC ODBC Good

to reduce space usage is to take the field names as short as possible, so that space is small, but this requires a tradeoff between legibility and space occupancy. I have suggested that the author put the field name index, each of the field names in one byte, so you don't have to worry about how long the field name takes. But the author's concern is not unreasonable, this index method needs to be a result of each query to replace the index value with the original value, and then send to the cli

Today I understand a function, I found that the database column name is actually Chinese, work more than six years to see. Only remember when school, our teacher said there will be compatibility and other issues, the specific has not been clearly written.I am a good thing Baidu, finishing up the answers given by the netizens, hope to help everyone.When we use the table and column names in Chinese, we first confirm whether the

because, because these columns have very few values, such as the gender column of the personnel table, in the results of the query, the data rows of the result set occupy a large proportion of the data rows in the table, that is, the data rows that need to be searched in the table are large. Increase the index,Does not significantly speed up the retrieval. (3) For those columns that are defined as text, the image and bit data types should not increase the index. This is because the amount of da

Label:Tasting Key-value Database (ii) The advantages and disadvantages of--MONGODBMongoDB's name is taken from the middle five letters of the English word "humongous" and is a database open source project developed by C + + based on Distributed file storage. His file storage format is Bson (binary JSON), which makes it

Label:Transferred from: http://blog.sina.com.cn/s/blog_5a8b8eb80100sg84.html First, the concept of the index An index is a way to speed up the retrieval of data in a table. The index of the database is similar to the index of the book. In books, the index allows users to quickly find the information they need without having to scroll through the entire book. In the database, the index also allows the

composite index, the total length of the columns that make up the composite index cannot exceed 900 bytes, which means that the composite column length cannot be too long; In a composite index, all columns must be from the same table, and composite columns cannot be created across tables In a composite index, the order of the columns is very important, so the order of the columns is carefully arranged, in principle, the most unique column should be defined first, for example, the index on (col1

This article introduces the database index, and its advantages and disadvantages. The features and applications of MySQL indexes are described in detail. This article analyzes how to avoid MySQL unavailability, how to use explain to analyze query statements, and how to optimize MySQL index applications. An index is a special file (an index on an InnoDB data table

Index category: Indexes can be divided into clustered indexes, non-clustered indexes, and unique indexes. Advantages: 1. The main advantage is convenient query and improved system performance. 2. By creating a unique index, You can ensure the uniqueness of each row of data in the database table. 3. The data retrieval speed can be greatly accelerated, which is also the main reason for creating an index. 4.

the form of a two-dimensional table! a two-dimensional table is made up of rows and columns, knowing that the row and column numbers will be able to locate the data in the table! Excel is a two-dimensional table! Easy to use, the basic common SQL language makes it easy to operate relational databases! SQL is supported , so complex queries can be made! easy to maintain, rich integrity (domain integrity, entity integrity, referential integrity, and custom integrity) greatly reduces data redun

updating data and deleting data. If you change the column in the WHERE clause in the update and delete to B, the speed is the same as no index because the index is invalid. Therefore, the index can greatly increase the query speed, for delete and update operations, if the column in the WHERE clause uses an index, even if the index needs to be re-build, it is likely that the speed is faster than not using the index. The index is obviously a burden on the insert operation. At the same time, the i