learning sql pdf

(@ "Successfully open database");1. Create a table[Self executesqlite:db withsql:@ ' CREATE table if not exists t_newtable (ID integer primary key autoincrement, name text, a GE integer, Math real) "];2. Inserting data[Self executesqlite:db withsql:@ "insert to T_newtable (name, age, math) VALUES (' Tom ', 10, 100) '];3. Query data[Self quarydata:db];} else {NSLog (@ "Failed to open database, failure code:%d", res_open);}}-(void) Executesqlite: (Sqlite3 *) db Withsql: (NSString *)

SQL Learning Notes (i)I. Retrieval of dataHow to use the SELECT statement to retrieve one or more data columns.1.1 Retrieving a single columnSELECT Prod_name from Productions;Note: The retrieved data is not sorted1.2 Retrieving multiple columnsSELECT Prod_id,prod_name,prod_pricefrom Productions;NOTE: SQL statements generally return raw, unformatted data.1.3 Retri

the underscoreINSERT into t05102_a values (""); Insert single quotation marksINSERT into t05102_a values (Chr (39) | | 1); Man ASCII View-derivedCREATE TABLE T05102_b (a number,b number);INSERT into t05102_b values (1,999);INSERT into t05102_b values (1,0);INSERT into t05102_b values (2,999);INSERT into t05102_b values (2,0);SELECT * from T05102_b order by a B;SELECT * from T05102_b ORDER by a desc, b desc;Select a "x", B "Y" from the T05102_b Order by "X" desc, "Y" desc; aliases, in order by t

like SQL server2008? I think there are two points of concern, one is to pay attention to your data volume, if the amount of data is difficult to more than 10,000, then choose a smaller lightweight Access database can be, but if your database data volume is large, it is recommended to use SQL Server database, Because the processing power and efficiency of the data are much higher.My personal situation is to

for storing, processing, and securing data, replication, full-text search, and tools for managing relational and XML data.Analysis Services services, tools for creating and managing online analytical processing (OLAP) and data mining applications.The Reporting Services service, a server and client component for creating, managing, and deploying tabular reports, Matrix reports, graphical reports, and free-form reports, can be used to develop extensible platforms for reporting applications.The In

procedureAdd_sal_procedure (dept_id Number,TempOut Number) is cursorSal_cursor is Selectemployee_id ID, hire_date HD, Salary sal fromEmployeeswheredepartment_id=dept_id; A Number(4,2) := 0;begin Temp:= 0; forCinchSal_cursor loop A:= 0; ifC.hdTo_date ('1995-1-1','YYYY-MM-DD') ThenA:= 0.05; elsif C.HDTo_date ('1998-1-1','YYYY-MM-DD') ThenA:= 0.03; ElseA:= 0.01; End if; Temp:= Temp +C.sal*A; UpdateEmployeesSetSalary=Salary*(1 +Awhereemployee_id=c.id; EndLoop; End;View Code2. Delete a

ID is the primary key, Stuid is the foreign key. The foreign key table must be a table that already exists.2. Change the data sheetYou may want to modify the structure or constraints of a table during the use of the data table. Alter is the instruction that is responsible for modifying the database object. For a database you can use ALTER TABLE TableName modification.modification is a clause that specifies the content of the modification.For example: Add a column to the table: ALTER TABLE test

;SELECT @ @TIMETICKS;SELECT @ @IDLE;SELECT @ @TOTAL_ERRORS;SELECT @ @IO_BUSY;SELECT @ @TOTAL_READ;--Read disk countSELECT @ @PACKET_ERRORS;-The number of network packet errors that occurredSELECT @ @TOTAL_WRITE; number of disk writes performed by--sqlserverSelect PatIndex ('%soft% ', ' Microsoft SQL Server ');Select PatIndex (' soft% ', ' Software SQL Server ');Select PatIndex ('%soft ', '

First, write it in front.Today is a double break again! Life is still going on, and when you stop, it may suddenly seem uncomfortable. Sometimes, see a thing, you will find the original in this society, excellent people a lot, silentlyThere are many people who struggle hard. Friday morning on time to work, buy breakfast, to the company's restaurant to eat breakfast, I met a person, maybe twice I will not pay attention, but every time I eat breakfast in the restaurant,Will meet him, I see him is

personnel learning. As an international certification in 147 countries around the world are widely recognized.Under the current tide of information security, talent is the key to the development of information security. and the current domestic information security personnel is very scarce, I believe security+ certification will become the most popular information security certification.This article is from the "11662938" blog, please be sure to keep

A picture of "ten" words: SQL Server Database Summary A rough summary. After a period of study, also has some knowledge of the database. The database is basically made up of tables, relationships, and operations; for beginners to learn first: 1. How the database stores the data Tables, Constraints, triggers 2. How the database operates data Insert,update,delete T-SQL function stored procedure triggers 3

Two days ago we learned some of the most basic database-related knowledge, starting today, we have shallow to deep learning database knowledge, for our future work to lay a solid foundation, for you Yimeimei can see clearly I want to express the meaning, From today, we also use the image format to each statement before and after the implementation of the data what changes have come up (blog Park just opened 5 days, inside a lot of things are not too f

SYSTEM: database operator can use the same password Direct Next (Default storage type and location) Direct Next (Default recovery configuration) Select the instance scenario (learning to use) Direct next (default initialization parameter) Direct next (Database storage) Click Finish Click OK (CREATE DATABASE profile) Select Password management after creation (change Scott's password to Tiger HR's password is hr) Ope

This article introduces the SQL stored procedure in terms of its concept, advantages, syntax, creation skills, and calling. I. Concepts, advantages and syntax of SQL stored procedures Before learning the program process, let's first understand what a stored procedure is? What advantages does stored procedure have? 　　Definition: Store commonly used or complex tas

a tableno new tables will be built, but deletes 3 in a row. InnoDB'srow locks are not absolute, at an indeterminate time (where xx like '%xx ') locks the entire table 4. Establisha good index, InnoDB can be as fast as 5 faster than MyISAM. InnoDBrow count is not saved, when executing the COUNT (*) statement, InnoDB needs to scan the entire table to calculate the number of rows, MyISAM only need to read the number of rows,but when the where condition is added, the two are the same speed Note: If

parameters is null, as shown in the following example:when modified with the set+if tag, if an item is NULL, it is not updated, but the database's original value is maintained. The following example: 3,trim LabelTrim is a more flexible place for the label of superfluous keywords, and he can practice the effects of where and set.The equivalent trim statement for the where example:the equivalent trim statement for the set example: Summary:In fact, in the real application, we are more using the

to the table schema) Case classPerson (Id:int, name:string, Age:int)4. Associate the Rdd and case class with Val Personrdd= Linerdd.map (x = = Person (x (0). ToInt, X (1), X (2). ToInt))5. Convert the Rdd to Dataframeval persondf=PERSONRDD.TODF6. Processing the dataframe persondf.show3, Dataframe common operation:DSL style Syntax//see what's in DataframePersondf.show//View the contents of the Dataframe section columnPersondf.Select(Persondf.col ("name"). SHOWPERSONDF .Select(Col ("name"), Col (

()) - { - //attaches the first entity to the current data context to track changes + DB2. Customers.attach (Cust); - //Attach related orders for tracking, otherwise they will be inserted at commit time + DB2. Orders.attachall (Cust. Orders.tolist ()); A //Update the customer's phone. atCust. Phone ="2345 5436"; - //Update the ShipCity of the first order Ordera. -Ordera.shipcity ="Redmond"; - //Remove the second order Orderb. - Cust. Orders.remove (Orderb); - //Add a new

frontline engineers. Suitable for banks, securities, insurance, internet companies and other IT-related personnel learning. As an international certification in 147 countries around the world are widely recognized.Under the current tide of information security, talent is the key to the development of information security. and the current domestic information security personnel is very scarce, I believe security+ certification will become the most pop

Tags: English learning note Translation BSP parsing modify MDA database system DashSure enough, although not hard not necessarily successful but give up will be very easy ... Well, the ACM road has gone to the end, although there may be a bit of an episode behind it, but the road to the point of performance is a certainty.SQL's learning note is a database system concept of the original English as the theme