learning sql pdf

create a new SQL window, and the file list below has the system and the database you created, which you can view.PL/SQL can also perform visual operations on Oracle.So the first time I installed PL/SQL, I said no listener, think about it. There should be no new folders and configuration of these two files, because these two tutorials are different in the final s

batches, stored procedures, the T-SQL in the trigger management. Extracting data blocks or multiple rows of data is not supported 2:API Cursors The main use on the server 3: Customer cursor Primarily when you cache a result set on a client computer by using the --------------------------------------------------------------------------------------------------------------- --------------------------------------------------------------------------------

optimistic numeric optimistic row version control lock silent unlocked unlocked unlocked not locked update NOLOCK unlocked unlocked unlocked unlocked HOLDLOCK shared share share update UPDLOCK Error Update update TABLOCKX error does not lock unlocked update other unlocked unlocked Unlocked update * Specifies that the NOLOCK hint will make the table specified for the hint in cursor is read-only Of16, use Profiler to track the query, get the time required to query, find out the problem of

Tags: database concepts and Creation1. First, before learning to create a database, as shown, let's first describe the type of database:650) this.width=650; "Src=" Http://s2.51cto.com/wyfs02/M02/8A/95/wKioL1g07YOB3bfEAABOxWnrXK8639.png-wh_500x0-wm_3 -wmp_4-s_2606502671.png "title=" qq picture 20161123091343.png "alt=" Wkiol1g07yob3bfeaaboxwnrxk8639.png-wh_50 "/>from the database Application Management Perspective , the

PL/SQL script language cursor usage learning notes (1), cursor usage learning (a), cursor refers to the pointer in a result set, through this pointer movement, we can traverse the entire result set www.2cto.com (B). Use the cursor step (1) Declare the cursor (2) Open the cursor (3) process the data in the cursor (4) Close the cursor (c) the most common cursor att

frequent exchange.Innodb_log_file_size: Single InnoDB log file size.Max_connections: Maximum number of connections4 loading the database into memory　　Put frequently accessed data into memory (e.g. 30% of data into memory)5 SSD Storage6 horizontal expansion??　Vertical expansionHorizontal Scaling7 Pursuit of Visualization　　Database is affected by traffic load, application and other errors, in order to quickly and effectively solve the problem, need to have a monitoring mechanism.Common monitoring

');insertintocoursevalues (' c009 ', ' PHP ', ' t003 '); insert intocoursevalues (' c010 ', ' EJB3.0 ', ' t002 '); commit;/*************** Initialization score Table **************** /insertintoscvalues (' s001 ', ' c001 ', 78.9); insertintoscvalues (' s002 ', ' c001 ', 80.9);insertintoscvalues (' s003 ', ' c001 ', 81.9); Insertinto scvalues (' s004 ', ' c001 ', 60.9);insertintoscvalues (' s001 ', ' c002 ', 82.9); insertintoscvalues (' s002 ', ' c002 ', 72.9);insertintoscvalues (' S003 ', ' c0

"SQL Injection vulnerability."SQL injection attacker's goal is only a little, is to bypass the program restrictions, is the user input data into the database execution, using the particularity of the database to obtain more information or greater permissions.Injection Vulnerability Classification:1. Digital InjectionWhen the input parameters are integer type, such as: ID, age, page number, etc. If there is

registered as a TA Ble=>tables can used in subsequent SQL statements.//SC is an existing sparkcontext.Val SqlContext =NewOrg.apache.spark.sql.SQLContext (SC)//This was used to implicitly convert an RDD to a DataFrame.Importsqlcontext.implicits._//Define the schema using a case class.//note:case classes in Scala 2.10 can support-only up to To work around this limit,//You can use custom classes that implement the Product interface. Case classPerson (na

Database PL/SQL script language function learning notes function build syntax rules: create [or replace] function function_name [(parameter,…)] Return datatype is variable declaration; begin statement ;... [Execption statement;…] The end; www.2cto.com function has only the IN mode parameter. The return value can be imported only from the calling environment, and the return type of the function can be return

Label:The 1.distinct is used to return a value that is removed from the duplicate and used to remove the select distinct name from student 2.select newid () generates a unique value that is not duplicated. Both globally unique identifiers The difference between 3.varchar and char: Although VARCHAR2 is more space-saving than char, if a VARCHAR2 column is often modified and the length of each modified data is different, this causes a ' row-migration ' phenomenon, which creates redundant I/O, which

1 distince value can be used for column name Distince ID cannot be distince *2 Time Function Day (getdate ()) Gets days year (GETDATE ()) Gets the month (GETDATE ()) months DateDiff (Day,getdate (), ' 2015-12-14 ') Gets the time difference, DateAdd plus DatePart Datename get part of time3 stored procedures in the final or SQL statement assembly, for the frequently used data source with temporary table, you can be a temporary table as a temporary varia

Label:First, create a table CREATE TABLE' student ' (' ID ')int( -) not NULLauto_increment, ' name 'varchar( -)DEFAULT NULLCOMMENT'name', ' subject 'varchar( -)DEFAULT NULLCOMMENT'Courses', ' score 'varchar(Ten)DEFAULT NULLCOMMENT'score', ' Stuid 'varchar( -)DEFAULT NULLCOMMENT'School Number', PRIMARY KEY(' id ')) ENGINE=InnoDB auto_increment=Ten DEFAULTCHARSET=UTF8; Second, insert data Third, SQL statement operations 1. Calculate the total numbe

JoinSystypes b onA.xtype=B.xusertypeInner Joinsysobjects D ona.ID=D.id andD.xtype='U' andD.name'dtproperties' Left Joinsyscomments E onA.cdefault=e.id Left JoinSys.extended_properties g ona.ID=g.major_id andA.colid=g.minor_id Left JoinSys.extended_properties F onD.id=F.class andf.minor_id=0 whereB.name is not NULL --where d.name= ' table to query '--if you only query the specified table, add this condition Order byA.id,a.colorder Other operations conform to the

Label:1.1 Create a database1.1.1 Create a default databaseCreate Database Db_sqldata (Db_sqldata is the DB name)1.1.2 to create a database that specifies the location of the database fileCreate DATABASE Mydatabase1On(Name=mydatabase1_data,Filename= ' E:\mydata\Mydatabase1_data.mdf ',Size=4,MAXSIZE=10,filegrowth=10%)Log on(Name=mydatabase1_log,Filename= ' E:\mydata\Mydatabase1_log.ldf ',Size=1,Maxsize=6,Filegrowth=1)Note: The SQL statement is case-inse

Tags: Click http rev to make an informational numbering relationship INF T-SQL statementModifying the properties of a data tableWhen you save the changes to the data table, you always get a warning that prevents changes.There are 2 ways to solve this problem:1. You can use T-SQL statements to forcibly modify2. Tools Option Designer Table Designer and Database Designer block save requirements Check outSet fo

Tags: class definition _id where begin update floor statistic cost 1 ---20161107, loop execution SQL statement 2 3 Declare @i int --Defining Variables 4 Set @i= $ 5 while @i106 --set up a loop condition 6 begin 7 --EXECUTE Statement 8 UpdateMms_t_d_mematstatistics9 Ten One --rand (): Returns a random number of 0-1; A --ceil (x): Returns the smallest integer greater than or equal to X; - --Floor (x), in contrast to Ceil (), produces the largest

The 1.SQL statement selects the first two records from the Websites table:SELECT * from Websites LIMIT 2; select TOP 50 PERCENT * from Websites 2. Wildcard charactersThe A.SQL statement selects all Web sites with the URL beginning with the letter "https": WHERE url like ' https% ' b.sql statement select name starts with an arbitrary character, then all customers with "Oogle" SELECT * from WebsitesWHERE name like ' _oo

1. Most SQL queries contain only a single SELECT statement that returns data from one or more tables, but SQL also allows multiple queries (multiple SELECT statements) to be executed and the result returned as a query result set. These combined queries are commonly referred to as and or compound queries.There are two main scenarios in which you need to use a combination query:(1) Return structure data from