default null

The tbl_direct_pos_201506 table has 1.9 million data. Ddl:CREATE TABLE ' tbl_direct_pos_201506 ' (' Acq_ins_code ' char () not NULL DEFAULT ' COMMENT ' agency code ', ' Trace_num ' char (6) N OT null default ' COMMENT ' tracking number ', '

1, the logical meaning of varchar (N)Starting with MySQL4.1, n in varchar (n) refers to the maximum number of characters (characters) that can be stored in the field, not the number of bytes. Whether it's a Chinese-English character or a number, or

First, import test data[Email protected] ~]# wget https://launchpadlibrarian.net/24493586/employees_db-full-1.0.6.tar.bz2Mysql> Source/root/employees_db/employees.sql;View:mysql> use employees;Reading table information for completion of table and

There may be some small details in the daily write SQL that cause the overall SQL performance to degrade several times or even dozens of times times, hundreds of times times. The following example is the performance loss caused by a single quotation

Next, Testchar (1) default NULL, char (1) NOT null default ', char ($) default NULL, char (+) NOT null default ' 'varchar (1) default NULL, varchar (1) NOT null default ' ', varchar ($) default NULL, varchar (+) NOT null default ' 'nvarchar (1)

CREATE DATABASE Db_studentinfo; Use Db_studentinfo;D rop TABLE IF EXISTS t_student; CREATE TABLE t_student (studentid varchar (+) NOT NULL, Stuno varchar (DEFAULT) NULL, stuname varchar DEFA ULT NULL, Stusex varchar (TEN) default NULL, Stubirthday

Create several tables ~ For a brief description, the tbl_post blog table tbl_comment comment table and the tbl_user table tbl_tag label table can directly run the following SQL statement. Create database /*! 32312 if not exists */'yii '/*! 40100

Create a few tables ~ simple explanation, tbl_post Blog table tbl_comment Comment table, tbl_user user table Tbl_tag Tag table run the following SQL directly. CREATE DATABASE/*!32312 IF not exists*/' yii '/*!40100 DEFAULT CHARACTER SET UTF8 */; Use

tbl_direct_pos_201506 table has 1.9 million data, DDL:CREATE TABLE ' tbl_direct_pos_201506 ' (' Acq_ins_code ' char () not NULL DEFAULT ' COMMENT ' agency code ', ' Trace_num ' char (6) N OT null default ' COMMENT ' tracking number ', '

Migrate the collection data in MongoDB to the MySQL database 1. Export data on mongodb and write expmongo. sh. The shell script is as follows: #! /Bin/shDatestr = 'date' + % Y-% m-% d''/Usr/local/mongodb/mongodb-linux-x86_64-2.4.4/bin/export-im_user-

Mysql combines multiple data entries corresponding to the same ID. This example describes how to merge multiple data entries with the same ID in mysql. We will share this with you for your reference. The details are as follows: For example: CREATE

Mysql optimization tool description, mysqlexplain I. Syntax {EXPLAIN | DESCRIBE | DESC} tbl_name [col_name | wild] {EXPLAIN | DESCRIBE | DESC} [explain_type] SELECT select_options explain_type: {EXTENDED | PARTITIONS} 2. Database preparation Table

Because MyBatis belongs to a semi-automatic ORM framework, the main job will be to write the mapping mapping file, but because the handwriting mapping file is prone to error, the data discovery has off-the-shelf tools to automatically generate the

Previously used Entity Framework 5.0, SqlHelper, Mybatis.net and other Orm, of course, SqlHelper does not count. Feeling is learning Chen Ben Very high, configuration is also more complex, especially mybatis is all XML, Meng forced ~~~~~ EF with

Author:skateTime:2014/12/23Database Availability Monitoring Tool[Email protected] tmp]#/db_availability--helpusage:used to view server Availability v0.1, (C) Copyright Skate 2014[-h]--host host--user user--passwd passwd [--port Port][--dbname dbname]

MYQL Query Tree Table results: Say, say the comments, comments replyThere are three table association tables:User's speaking table (Ixt_customer_note)Talk about the comment form (ixt_customer_note_comment)Reply form for Comments

Key differs from primary keyKey is usually the index synonym. If the keyword attribute primary key is given in the column definition, then primary key can also be specified as key only. The purpose of this is to be compatible with other database

Database designin the system design process, the database is also a link can not be ignored, the database design is related to the stability of the system, so each information management, must be designed, the following is the database of the

This article illustrates the MySQL implementation method that merges multiple data with the same ID. Share to everyone for your reference, specific as follows: Such as: CREATE TABLE ' c_classuser_tab ' ( ' Id ' int () NOT NULL

Oracle apps The API to modify user passwords method One: Fnd_user_pkg.updateuser (recommended way) --Change password of Test_user to oracle123 (does don't ask for reset on I logon) BEGIN Fnd_user_pkg.updateuser (X_user_name =>