if not exists

Before you start using the database, make sure you have installed the appropriate database access library. For example, for MySQL database, use Mysql-connector client to connect. Download MySQL data and install: Download from the following

JS calls local database main JS file var HD = { Is_db:null, Uid:null, Ukey:null, ShortName: ' HD ', Version: ' 1.0 ', DisplayName: ' hd_2345 ', maxsize:100000, Data:null, Other:null, Login:null, Index:null, Creating a Database Initdatabase:function (

In the SQL name, if not exists if it does not exist, if exists if it exists. Below, learn the use of both. A to determine if the database does not exist Copy Code code as follows: If not EXISTS (SELECT * from sys.databases WHERE

Reprint Please specify source: https://blog.csdn.net/l1028386804/article/details/80173778I. Hive Overview 1, why hive is used The birth of the Hadoop ecosystem brings dawn to efficient and fast processing of big data, but requires writing mapreduce

A partitioned table is available for the following scenarios1: The table is so big that it can't be put all in memory, or only the last part of the tag has hot data, the others are historical data2: Partitioned table data is easier to maintain. For

--Complete the SQL exercises in the project footage and save the written SQL files and runs, and then submit them as jobs.--Design a student performance database that contains information about students, teachers, courses and accomplishments, and

MySQL Event learningIn System management or database management, it is often imperative to execute a command or SQL statement periodically. Anyone familiar with the Linux system knows the Cron scheduling task of Linux, and it is easy to implement

First, prepare the data# Create databases and tables under my MySQL and insert a few data mysql> CREATE database if not EXISTS student default character set UTF8 collate Utf8_gen Eral_ci; mysql> use student; Mysql> CREATE table if not exists

Under CentOS7, the official MySQL RPM package is mariadb and can be viewed MARIADB package information[Email protected] ~]$RPM- qi mariadb # requires first installing the package NAME:MARIADB # Name epoch:1Version:5.5.52 # VersionRelease:1. EL7 #

1. Creation, modification and deletion of databaseCreate:CREATE {DATABASE | SCHEMA} [IF not EXISTS] db_name [create_specification];For example:CREATE DATABASE IF not EXISTS test CHARACTER SET ' GBK ' COLLATE ' gbk_chinese_ci ';Modify:ALTER {DATABASE

Originating From: http://blog.chinaunix.net/uid-20639775-id-3323098.html MySQL Event learningIn System management or database management, it is often imperative to execute a command or SQL statement periodically. Anyone familiar with the Linux

1.FMDB is a large data storage method in iOS, it is the package class of SQLite, it is very useful2. You can go to the Githud above Fmdb package class3.FMDB uses a few steps: import the downloaded files into Project engineering, then add the sqlite3.

Cross tabulation-verifying the existence of objects (3) cross tabulation-verifying the existence of source objects through the sysobjects table. all three provided columns are checked to see whether the provided source object exists in the

Translation: create database statement, createdatabase This article is the translation of the mariadb official manual: create database. Original article: https://mariadb.com/kb/en/create-database/Https://mariadb.com/kb/zh-cn/create-database/ I

Basic Mysql partition management operations: I haven't written a blog for a long time. I have been learning Mysql partition for the past two days. Summary: Mysql supports Horizontal partitioning and does not support Vertical partitioning; Horizontal

1. Via Hive ViewCREATE EXTERNAL TABLE if not exists finance.json_serde_optd_table (RetCode string, retmsg string, data array>) ROW FORMAT SERDE ' org.apache.hive.hcatalog.data.JsonSerDe ' location ' hdfs://wdp.xxxxx.cn : 8020/nifi/finance1/optd/';

The fourth chapter: HQL data definition1: Create a databaseCreate DATABASE Financials;Create database if not exists financials;2: View Databaseshow databases;Fuzzy Query DatabaseShow databases like ' h.* ';3: Create database to modify the default

Sharing the latest website creation (fiction site) (2) -- creating a database and a data table and creating a website -- The most important link in the backend of php development is to create a database and create a data table. because it has a

Sqlitedatabase class:I. Manipulating databases with SQL statementsSqlitedatabase db = Openorcreatedatabase ("database.db", mode_private,null);//(database name, permissions, Data Factory)Db.execsql ("CREATE table if not exists USERTB (_id integer

HTML5 's Web SQL database implements Simple object persistence with local and session storage, dealing with cumbersome relational data. This is described in the Web SQL Database Specification for the Consortium (referenced): Web SQL database