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Tags: for customer service open source application Apr Date Specify write preA large part of the data is handled by a relational database management system (RDBMS). The 1970 E.f.codd's paper "A Relational model of data for large shared data banks", which makes data modeling and application programming easier. The application proves that the relational model is we
Intention lock
The database engine uses intention locks to protectLock hierarchyTo prevent other transactions from causing damage to the locked resources and improve the lock conflict detection performance. For exampleTableIn the requestPageTransactions before the shared lock (s lock)Table-level request sharing intention lock. This prevents other transactions fromTableAnd modify the entire table. Intention locks can improve performance becauseThe
system function structure diagram you generally are how to draw, I use organization chart or Visio, feel a little low ah, lazy time directly with xmind this kind of mind map software painting, the effect is also good.
Database modeling I have been using powerdesign, or navicat the reverse database to the model (because now very few databases will do physical fore
use the same Lmdb storage at the same time as a means of scaling performance. In addition, Lmdb does not require a transaction log (thereby improving write performance by not requiring two write data) because it maintains data integrity through the design itself.Lmdb uses B + Tree data structures internally. Its design efficiency and footprint are small, with unexpected side effects that provide good write performance. The Lmdb has an API similar to BerkeleyDB and dbm. Lmdb treats the computer'
when executing an SQL statement, the InnoDB table also locks the full table, such as the Update table set num=1 where name like "2%"6.InnoDB Support ThingsSelect the storage engine to select according to the actual situation.In general, if the query is more recommended to use MyISAM.If you need transaction processing or foreign keys, then InnoDB may be a good way.Ways to optimize MySQL database:1, choose t
Refer to this question: Https://segmentfault.com/q/10 ...
Since the encoding of the actual stored data depends on the encoding of the data table, what part of the encoding does the database encoding refer to? Meta data?
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Refer to this question: Https://segmentfault.com/q/10 ...Since the encoding of the actual stored data depends on the encoding of the data table,
that the language was actually a tool (the younger brother learned Java, but he was caught by the teacher to do the php project .... ~~~~ (>_
The core is thinking,
So I understand what development experience is.
For example, if you do not understand Java, but you have a project development experience,
There will be fewer detours,
Because many ideas are the same,
What should I do if the database is normally accessed with PHPMYADMIN but cannot be exported? A database of the school is used to change the platform. To MSSQL, but the data cannot be obtained.
Access using PHPMYADMIN and DBKISS is
: What is the difference between MyISAM and InnoDB in mysql? How to optimize the MYSQL database ?, If you are interested in the PHP Tutorial, refer. Basic differences between MyISAM and InnoDB
1. InnoDB does not support FULLTEXT indexes.
2. innoDB does not store the specific number of rows in the table. that is to say
Label:Use databaseDECLARE @ProcName varchar (50)Create Table #tmpName (Content varchar (2000))Create Table #tmp (procname varchar, Content1 varchar (8000))--Define a cursorDECLARE Searchproc CURSOR for--Query the name of the stored procedure in the database, as far as possible to remove the system proc, can be based on the Crdate time field to find non-system procSelect name from sysobjects where type= ' P ' and name
Label:To view the current version of the database: select version (); ==> View MySQL version (view in library)
+------------+
| version () |
+------------+
| 5.5.32-log |
+------------+
1 row in Set (0.00 sec)
status; ==> View current database status, including database version, current user, socket, etc.
--------------
mysql Ver 14.14 distrib 5.5.32, for L
What technology is involved in the development of WAP Web site, the background with PHP, database with MySQL, how to deal with the front end?
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What technology is involved in the development of WAP Web site, the background with PHP,
less storage space than a string, so it is preferable to select the index keyword. 3. The field with fixed storage space is more suitable for the keyword chosen as index. Fields of type char are better suited to be selected as Index keywords than fields of type text. 4. The fields that are used frequently in the Where clause should be indexed, the grouping field or the Sort field should be indexed, and the
Look at the online data with the text type effect efficiency
What type of field is it used for? Save graphic format
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Look at the online data with the text type effect efficiency
What type of field is it used for? Save graphic format
textand longtext all can.This light forum
RAM2), when RAM is 2-16GB, swap size is recommended equal to RAM size3), Ram greater than 16GB, swap size recommended 16GB4, large memory environment swap size configuration recommendationsDue to the rapid decline in memory prices, the current production system server memory 256GB, 512GB is no surprise, the author recommends 16-64gb physical memory, swap and phy
Experienced in person, the response speed is very fast, than from the database to read the article much faster, but this way always feel there will be sequela.
Is this approach suitable for personal small sites? (no complex features such as user registration and commenting)
Can this framework be applied directly to the production environment?
Label:four categories of NoSQL databaseskey value (key-value) store databaseThis type of database primarily uses a hash table that has a specific key and a pointer to the specific data. The advantage of the Key/value model for IT systems is simplicity and ease of deployment. But if the DBA only queries or updates part of the value, Key/value becomes inefficient.
Reprint Please specify source: Jiq's technical BlogHBase Features:Recently in the learning Hbase,hbase based on the row Jian is indexed, the query speed will be very fast, completely real-time.But if HBase is to query based on fields other than row health, it can only be a full-fledged scan, which is basically unacceptable.So HBase will generally be designed for
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