This presentation reveals many important aspects of the CUBRID Database, including its unique features, future roadmap, comparison with other databases, architecture, etc.

1. CUBRIDDeveloper's Course Author: Bomyung Oh Team / Department: DBMS Development Lab Author(2): Kyungsik Seo Team / Department: DBMS Development Lab

5. Triggers

6. Stored Procedure

7. AUTO_INCREMENT

8. Query Plan Cache

9. Query Result Cache

10. Replication

11. Partitioning

13. Triggers

14. Stored Procedures

15. AUTO_INCREMENT

16. Query Cache

17. Replication

18. Full Text Indexing

19. Partitioning

20. Event scheduler

21. MySQL Cluster

22. XML Functions4.1 4.0 3.23 2003 2001 2002 2004 2005 2006 2007 2008 2009 2010

23. Who are using CUBRID Over 100,000 Downloads

24. Introduction to CUBRID Overview and Architecture of CUBRID Using CUBRID Introduction to CUBRID HA

25. 1.1 Overview and Architecture of CUBRID

28. CUBRIDArchitecture (Detailed) CUBRID Manager GUI CUBRID Manager Interface ODBC CCI PHP OLE DB Python Ruby JDBC CM Server Broker Job Queuing Monitoring Connection Pooling Logging Client Library Native C API Parser Object Manager Schema Manager Transaction Manager Query Transform Workspace Manager Query Optimizer Memory Manager Plan Generation Communication Module Server Admin Utility Communication Module Create, Delete, Copy, Rename Transaction Manager Log Manager Lock Manager Query Manager Access Method B+Tree Module File Manager System Catalog Module Add Volume Buffer Manager Load / Unload Disk Manager Backup / Restore Active Log Compact / Optimize File Based Objects Data Volume Index Volume Temp Volume Check / Diag Archive Log

29. CUBRIDProcess (Detailed) JDBC driver CCI library API connect query & result port listening query & result File cub_broker cubrid_broker.conf fork parse descriptor pass Process cub_cas cub_cas shared memory csql cubridcs.so cubridcs.so Dynamic shared library connect cubridcs.so request & response TCP job queue multi-thread port listening parse descriptor pass parse cub_master cub_server cubrid.conf UDS cubrid.so mount (read/write) register read volume file log file databases.txt volume file log file cub_admin cubridsa.so

30. 1.2 Using CUBRID

31. Prerequisites for Installation Download CUBRID http://sourceforge.net/projects/cubrid Check supported platforms (Linux/Windows) uname –r rpm –qa | grepglibc Install JRE version 1.5 or higher and set up the environment variables(CUBRID Manager) http://java.sun.com/javase/downloads/index.jsp For Linux For Windows Visual C++ 2008 distribution pack installation Create DB users (multiple instances) http://www.microsoft.com/downloads/details.aspx?displaylang=ko&FamilyID=9b2da534-3e03-4391-8a4d-074b9f2bc1bf Install and launch CUBRID

33. For detailed information, see the manual provided at the following link:. Run the exe file to start the installation wizard.http://www.cubrid.org/manual/gs/gs_install_windows.htm

34. Starting CUBRID Service in the CUBRIDtray

35. How to install CUBRID and start CUBRID Service in the Linux environment

40. CUBRID Manager is a tool used to control the functions of servers and brokers, andto monitor and analyze logs

42. CUBRID Manager - stop Stop DB Server Disconnect from the host Stop CUBRID Manager

43. 1.3 Introduction to CUBRID HA

45. No-Automatic Fail-over  No-Automatic Sync

46. HA

48. HA Configuration and Usage– Broker Redundancy AP Web Server AP Web Server JDBC Driver CCI Library Automatic failover Fail-back Fail-over Broker #2 Broker #1 Node Fail Active Server Standby Server Replication

49. Diagram of HA Architecture (Detailed) Async Update Select A-Node Active Server Node S1-Node Standby Server Node applylogdb coyplogdb applylogdb coyplogdb Server Active Replica Standby Semi-Sync Sync active log archive logs A-node’s active & archive logs S1-node’s active & archive logs active log archive logs Replication Log is not included Replication Log is included #Configurations# #A-Node’s log path S1-Node’s active & archive logs = $CUBRID_DATABASES/database-name_S1-Node-hostname (ex. /home1/cubrid1/DB/tdb01_Snode1) copylogdb & applylogdberror logs = $CUBRID/log #S1-Node’s log path A-Node’s active & archive logs = $CUBRID_DATABASES/database-name_A-Node-hostname (ex. /home1/cubrid1/DB/tdb01_Anode1) copylogdb & applylogdberror logs = $CUBRID/log #Configurations# A-node & S1-node’s <cubrid.conf> ha_mode=yes ha_node_list=hagrpname@A-node:S1-node A-node & S1-node’s <cubrid-ha> CUBRID_USER=username DB_LIST=‘dbname‘ broker node’s <databases.txt> dbnamevol_pathA-node:S1-nodelog_path

50. 2. CUBRIDArchitecture CUBRIDVolume Structure CUBRIDParameters Broker Parameters Error Log File System Catalog

51. 2.1 CUBRIDVolume Structure

53. **: A CUBRID file can be separated to multiple CUBRID volumes.File_1 File_2 File_3 Free_Pages Volumes

54. DB Volume Structure

56. Data volume

57. Saves the data of an application, such as tables or records

58. A record storage file, called heap, is created in a data volume

59. Index volume

60. A volume in which B+Tree indexes are saved for faster data access or queries

61. Temp volume

62. A volume in which intermediate results are saved to fetch result sets that exceed the size of the memory buffer, or to execute join queries

63. A temporary volume with an appropriate size must be created when creating a DB volume.

64. This is a permanent volume that is used for temporary purposes, and is different from temporary volumes that are used only temporarily.

65. Generic volume

66. The initial volume during DB creation, which can be used as the data, index, or temp volume.

68. The active log volume includes the most recent updates that have been applied to a database.

69. Records the status of a committed, aborted, or active transaction.

70. It is used to recover a DB from a storage media failure.

71. When the space allocated to an active log is completely used up, the content of the active log will be copied to and stored in a new log (archive log).

73. Volume Information

74. Includes the location information on DB volumes to be created or added

75. This file cannot be manually modified, deleted, or moved.

76. The name of the file is in {dbname}_vinf format.

77. Log Information

78. Records the information of the current logs and archive logs

79. Records the information on a new archive log file and unnecessary archive log file.

80. The name of the file is in {dbname}_lginf format-5 C:UBRIDatabasesemodbemodb_vinf -4 C:UBRIDatabasesemodbemodb_lginf -3 C:UBRIDatabasesemodbemodb_bkvinf -2 C:UBRIDatabasesemodbemodb_lgat 0 C:UBRIDatabasesemodbemodb 1 C:UBRIDATABA~1emodbemodb_x0010 COMMENT: CUBRID/LogInfo for database /CUBRID/databases/demodb ACTIVE: /CUBRID/databases/demodb_lgat 5000 pages ARCHIVE: 0 /CUBRID/databases/demodb_lgar000 0 4997 COMMENT: Log archive /CUBRID/databases/demodb_lgar000 is not needed any longer unless a database media crash occurs.

82. Records the location and backup information of a backup volume

83. Located in the same path in which log files are stored.

84. The name of the file is in {dbname}_bkvinf format.0 0 /Backup/demodb_bk000 0 level full backup of the first file. 0 1 /Backup/demodb_bk001 0 level full backup of the second file. 1 0 /Backup/demodb_bk100 1 level incremental backup of the first file. 2 0 /Backup/demodb_bk200 2 level incremental backup of the first file. The path information of a backup file Backup level information The sequence number of a backup volume per level

86. Contains the name, path, and the name of the built host of a DB.

87. Records the information related to the DB that is created in the databases.txt file upon the creation of a DB.

88. Saved to the path in which the $CUBRID_DATABASES environment variables are specified.

89. If it does not exist in the directory specified by the environment variable, the current directory will be used instead.

90. Caution

91. If a host name has been changed or a DB deleted by an OS command, this file must be modified as well.

92. As the user must be able to modify the databases.txt file during DB creation or deletion, the user must have the privilege to write to this file. If a user without the appropriate privilege attempts to create a DB, the DB creation will fail. For this reason, a DBA should enable the user-write privilege for the directory, or create a databases.txt file in the directory of each user and configure the environment variables.demodb /CUBRID/databases/demodb hostname /CUBRID/databases/demodb DB name DB path Host name DB log path

94. Distributes data, index, temp, and log volume so that they are separated from each other

95. Avoids the disk bottlenecks and improves disk management

96. Distributes volumes that can be used simultaneously

97. data & log, data & index, data & temp

98. Configures a volume to an appropriate size to prevent it from adding more volumes while in service

99. Data, Index, Temp, Active Log: Page size and the number of pages must be considered

102. A file in which the value of CUBRIDsystem parameters are saved.

103. The file is located in a subdirectory of $CUBRID/conf . You are recommended to specify different values from one DB to another DB in the DB.

104. There are two types of parameters: DB server parameters and DB client parameters. If a parameter has been changed in a process, that process must be restarted.

105. SQL is used to change a client parameter.

106. Syntax for configuring parameters

107. Case-insensitive

108. The name and value of a parameter must be inserted on the same line.

109. An equals sign (=) can be used, and a blank character can be added at both sides of the sign..

110. If the value of a parameter is a string, insertthe string without quotation marks. If a blank character is included in the string, encase it with quotation marks. [commom] data_buffer_pages=250000 [demodb] data_buffer_pages=500000

112. Add CUBRID_ at the beginning of the parameter to configure it as an environment variable

113. Configuring with an SQL statement

114. Only client parameters can be configured

115. Use “;” for multiple configurationsEnvironment Configuration File- $CUBRID/conf/cubrid.conf set CUBRID_SORT_BUFFER_PAGE=512 SET SYSTEM PARAMETERS 'parameter_name=value [{; name=value}...]‘ SET SYSTEM PARAMETERS 'csql_history_num=70’ SET SYSTEM PARAMETERS 'csql_history_num=70; index_scan_in_oid_order=1'

117. The number of data pages cached to the memory by a DB server

118. Requires an amount of memory equivalent to num_data_buffers times database page size (the page size specified when the DB is initialized; default is 4KB). (The size of the required memory is 100MB if the default is 25,000)

119. The actual size of a DB, the size of the memory, and the number and size of other processes must be considered when determining the size

120. The larger the value, the more data needs to be cached to the memory, which means less disk I/O. However, a value that is too large will cause the full swapping of page buffers.

121. index_scan_oid_buffer_pages

122. Configure the number of buffer pages in which the OID list is to be temporarily stored when scanning indexes

124. The number of pages used to process queries that require sorting.

125. One sort buffer is allocated to each active client request.

126. The allocated memory is released upon the completion of sorting.

127. A value between 16 and 500 is recommended.

128. temp_file_memory_size_in_pages

129. Determines the number of buffer pages that cache the temporary results of a query

131. Configures the interval of a checkpoint execution in min./page

132. The larger the value, the more time it takes to recover a DB.

133. media_failure_support

134. Configures whether to keep an archive log in the event of a storage media failure

135. If it is configured to the default value (yes), all active logs will be copied to and stored in an archive log when changes are made to a transaction while the active logs are full.

137. A parameter used to manage transaction concurrency

138. It must be an integer from 1 to 6 or a character string (Default: 3)

139. The larger the value of the parameter, the lower the concurrency

140. SERIALIZABLE: Inaccessible until transaction is complete

141. REPEATABLE: S_LOCK is maintained until the transaction is complete at SELECT

142. READ UNCOMMITTED: Allows incomplete transactions to be read

144. Configures the interval, in seconds, of deadlock detection for stopped transactions.

145. Resolves deadlock by rolling back one of the deadlocked transactions

146. The default value is 1sec.Be sure not to set the interval to a large number, as doing so will allow deadlocks remain undetected for that length of time.

147. lock_escalation

148. Converts to table lock if the number of row locks belonging to a table is greater than the specified value.

149. The default value is 100,000.

150. If this value is small, the table management overhead will be reduced, but the concurrency will be decreased.

151. If this value is large, thetable management overhead is will be increased, but the concurrency will be improved.

152. lock_timeout_in_secs

153. Specifies the waiting time of a lock

154. If the lock has not been allowed within the specified period of time, the transaction is cancelled, and an error is returned.

156. Configures the maximum number of query plans to be cached to the memory (Default: 1,000)

157. If this value is lower than 1, it will not work - it works only when the value is at least 1.

158. Configures the hint so that query execution plans are created without using cache

159. Use /*+ RECOMPILE +/ in queriesselect /*+ RECOMPILE */ * from record where …

161. Limits Data Definition Language (as known as DDL)

162. The default value should not be no.

163. block_nowhere_statement

164. It does not execute queries if there are no WHERE clauses in an UPDATE/DELETE statement.

165. The default value should not be no.

166. single_byte_compare

167. When comparing strings, set it so that it will compare the strings by a single byte.When using Unicode, set it to Yes (for UTF-8).

169. cubrid_port_id

170. Master Process Port

171. The default valueis 1523

172. If 1523 is already in use, the parameter must be changed to another port number.

173. Client/server request-related

174. max_clients

175. This number represents maximum number of DB clients that can be connected to a DB server at the same time, which by extension also means the total number of concurrent transactions. (Defaultvalue:50)

176. The actual number of concurrent users must be considered

177. DB Server restart configuration

178. auto_restart_server

179. Automatically restarts a DB server that has been stopped due to a failure

180. The default value when restarting the DB is yes.

182. async_commit

183. Enables the asynchronous commit function (Default value: must not be set to no)

184. Returns a commit to a client before the commit log is flushed to a disk

185. When a failure occurs in a DB server, all commit transactions that have not been flushed to a disk will not be able to be recovered.

186. group_commit_interval_in_msecs

187. Collects commits that have occurred during the setting in a group, and executes them (Default value: no need to configure)

190. Configuration file: $CUBRID/conf/cubrid_broker.conf

191. The file can be modified in an editor. Any changes made will be applied when the Broker restarts.

192. To modify the configuration without a restart, use the following command:

193. Configurable environment variables

194. APPL_SERVER_MAX_SIZE, SQL_LOG, TIME_TO_KILL

195. SESSION_TIMEOUT, KEEP_CONNECTION

196. If an environment variable and its value are incorrect, an error will occur during the restart, which will prevent the restart.% broker_changer <br-name> <conf-name> <conf-value> % broker_changerbroker1sql_log on OK

197. Introduction to Broker Parameters

198. Introduction to Broker Parameters

199. Introduction to Broker Parameters

200. 2.4 Error Log File $CUBRID/log/ $CUBRID/log/server/ $CUBRID/log/broker/ $CUBRID/log/broker/sql_log $CUBRID/log/broker/error_log CUBRRENT_DIRECTORY, $HOME

202. The connection log is a record of the time it takes for each CAS to process a request by Broker.

203. This log has the name of "<broker name>.access" and resides in a directory specified in the ACCESS_LOG of cubrid_broker.conf.1 192.168.100.201 - - 1158198049.151 1158198049.246 2008/09/14 10:40:49 ~ 2008/09/14 10:40:49 29438 - -1 2 192.168.100.201 - - 1158198049.401 1158198049.406 2008/09/14 10:40:49 ~ 2008/09/14 10:40:49 29438 - -1

205. Records the information about an error that has occurred while processing the request from an application client into the broker_name_app_server_num.err fileTime: 02/04/09 13:45:17.687 - SYNTAX ERROR *** ERROR CODE = -493, Tran = 1, EID = 38 Syntax: Unknown class "unknown_tbl". select * from unknown_tbl

208. (39) : The sequence number of the SQL statement group, for prepared statement pooling

209. (PC) : Uses the content stored in the plan cache

211. 2.5 System Catalog

213. Tableinformation

214. db_class

215. Important fields: class_name and owner_name

216. Column information

217. db_attribute

218. Important fields: class_name, attr_name, and attr_type

219. Other

220. db_vclass

221. db_index

222. db_index_key

223. db_trig

224. db_partition

225. db_stored_procedure

228. 3.1 Types, Operators, and Functions

229. CUBRIDIdentifiers

230. CUBRID Data Types

231. CUBRID Data Types

232. CUBRID Operators

233. CUBRIDFunctions(2008 R3.0 based)

234. CUBRID Functions

235. 3.2 Comparison of Major SQLs

237. Saves and displays the character set configured in an application as it is.

238. Can specify a character set via the JDBC connection url.

239. Does not support multi-byte characters.

240. Column sizes must be defined to allow sufficient space for multi-byte characters.

241. The length or position value in a string function is processed byte by byte.

242. Functions for joining DBs are not supported.

243. Cannot change the column size by using the ALTER TABLE statement.

244. This will be fixed in a future version.

245. If the prepare statement pooling is used, only one result set can be handled per connection.

247. Pagination(LIMIT RESULT SET) ROWNUM SELECT select_list FROM TABLE1 T1 WHERE T1.A = 'test' AND ROWNUM <= 100 ORDER BY ORDER_COLUMN; ORDERBY_NUM() SELECT select_list FROM TABLE1 T1 WHERE T1.A = 'test' ORDER BY ORDER_COLUMN FOR ORDERBY_NUM() <= 100; LIMIT (from R3.0) SELECT select_list FROM TABLE1 T1 WHERE T1.A = 'test' ORDER BY ORDER_COLUMN LIMIT 1,100;

248. AUTO_INCREMENT and SERIAL SERIAL CREATE SERIAL SERIAL_NAME START WITH 1 MAXVALUE 1000 NOCYCLE; CREATE TABLE TABLE1( seqnumINT, name VARCHAR); INSERT INTO TABLE1 VALUES (SERIAL_NAME.next_value, 'test'); //seqnum=1 AUTO_INCREMENT CREATE TABLE TABLE1( seqnum INT AUTO_INCREMENT(1,1000) NOT NULL, name VARCHAR); INSERT INTO TABLE1 (name) VALUES ('test'); //seqnum=1

251. Configure an index for columns with a good distribution (narrow range), basic keys, and columns which are the connection point for a join.

253. If no index name has been specified, it will be automatically created.

255. Scans indexes only when the cost of index scan specified in the USING INDEX clause is lower than the sequential scan.

256. USING INDEX The index scan is executed unconditionally in the case of index_name(+).

257. For USING INDEX NONE, the sequential scan is executed unconditionally.

258. If more than two index names are specified behind the USING INDEX clause, the appropriate index will be selected by the optimizer.

260. When comparing the value of an index column to NULL,there will be no index scan.Modifying query

261. Create an index to be able to cover search conditions

262. Create an index to be able to cover the ORDER BY sorting condition

266. card: Number of records in an expected result set

267. page#: Expected number of page accesses

268. sel(selectivity): Expected selectivity that satisfies search conditions(card, page#) sel

271. Example of a Display Query Plan (m-join) SELECT/*+ USE_MERGE */ * FROM game, athlete WHEREgame.athlete_code=athlete.code;

272. 4 JDBCandOther Management JDBC Programming Transaction Management

273. 4.1 JDBC Programming

274. The SQL Type and the Java Type

279. ResultSetMetaData

280. Send SQL statement Fetch row Get columns Yes More columns No Yes More rows No ResultSet ... … Connection myConnection = DriverManager.getConnection(url,”user”,”passwd”); Statement myStatement = myConnection.createStatement(); ResultSetrs = myStatement.executeQuery(“SELECT name, title, salary FROM employee”); int I = 0; while (rs.next()) { I++; String empName = rs.getString(“name”); String empTitle = rs.getString(“title”); long empSalary = rs.getLong(“salary”); System.out.println(“Employee ” + empName + ” is “ + empTitle + “ and earns $” + empSalary); } … ...

282. Make sure to return a DB object such as ResultSet or Statement,Connection after it is used.

283. Return occurs when the close() method is called for a corresponding object.

284. If AutoCommit False is used, return occurs after the transaction for a connection(Commit/Rollback) is explicitly finished.

285. If you execute inner query statements, you must allocate a different connection object to each of them.

286. When other transactions occur in a cycle statement that uses retrieved data

289. Lockis managed for each transaction, for tables and records

290. For a record, S-lock is acquired for reading, and X-lock is acquired for writing.

291. To get S-lock for a record, you must get IS-lock for the corresponding table.

292. To get S-lock for a record, you must get IX-lock for the corresponding table.

293. Features

294. Configuring SIX-lock for a table

295. When a transaction that has S-lock for a table requests X-lock

296. Valid range of lock

297. X-lock : The time a transaction is finished (i.e., confirmation or withdrawal time)

299. When reading the schema of a corresponding table

300. When reading the higher-tier or lower-tier table of a corresponding table

301. When the number of records a transaction reads is greater than the lock_escalationvalue

302. Configuring X-lock for a table

303. When modifying a corresponding table

305. Creates an object for lock object unit: table, record)

306. Displays information for each object

307. Provided information

308. Lock related configuration of a DB server

309. Information of DB clients connected to a DB server

316. For CAS, check its information in the CUBRID broker.

317. Check the order of ID in a broker by using a processID.

318. As the process IDs in the above example are 2908 and 2980, they correspond to ID1 and ID2 of query_editor broker.

319. As 2980is occupying X_LOCK, the corresponding transaction (ID2)must be forced to stop, if necessary.

320. For an application, logic change, etc. may be necessary for the application.

322. Forcibly stop the corresponding transaction (rollback) by using the Killtran command% usage: cubridkilltran [OPTION] database-name valid options: -i, --kill-transaction-index=INDEX kill transaction with transaction INDEX --kill-user-name=ID kill all transactions with user ID --kill-host-name=HOST kill all transactions with client HOST --kill-program-name=NAME kill all transactions with client program NAME -p, --dba-password=PASS password of the DBA user; will prompt if don't specify -d, --display-information display information about active transactions -f, --force kill the transaction without a prompt for verification

323. 5 Practice

324. CUBRID Installation Installing CUBRID (for Windows) Downloading and installing CUBRID. Creating demodb Checking if the CUBRID service tray has started Checking if the CUBRID service has started service, process

325. CUBRID Installation CUBRID manager client Checking if DB is created Starting DB server Checking if there is aJAVA related error message during start Using the Query Editor Executing a simple query: select * from db_class

326. CUBRID Installation Stopping DB Server Stopping CUBRID service Checking process Starting CUBRID service

327. DB creation Creating a DB that satisfies the following conditions Creation location and size of each volume Page size: 4Kb First volume: 5,000p, C:UBRIDatabaseslt;DB name> Log volume: 100,000p, C:UBRIDatabaseslt;DB name>og Data volume: 500,000p, C:UBRIDatabaseslt;DB name> Index volume: 250,000p, C:UBRIDatabaseslt;DB name> Temp volume: 250,000p, C:UBRIDatabaseslt;DB name>

328. DB creation Checking the created volume Checking the content of databases.txt Checking the files in each directory by referring to the volume information file control volumes information volumes log volumes Computer name

329. Schema management Creating a table that satisfies the following conditions Company table (company) Company ID (integer): primary key, company name (string) Customer table (client) CustomerID (integer): not duplicated Customer name, title, email, telephone no., address: Character string create table company ( comp_idint primary key, // company ID comp_namevarchar(200) // company name ); create table client ( client_idint primary key, // customer ID comp_idint, // company ID client_namevarchar(20), // customer name title varchar(10), // title email varchar(100), // email phone varchar(20), // phone no. address varchar(200), // address );

330. Schema management Viewing table information in a CUBRID Manager client

331. Schema management Modifying a table according to the following conditions Re-creating after deleting a primary key Changing type Title: charvarcharor varchar char Adding/changing an initial value Title: Specifying an initial value to ‘new staff’ and deleting it alter class client drop constraint pk_client_client_id alter class client add primary key(client_id) // or (possible to assign PKname),alter class client add constraint pk_id primary key (client_id) alter class client rename attribute title as old_title alter class client add attribute title char(20) update client set title = cast(old_title as char(20)) alter class client drop attribute old_title alter class client change title default 'new staff' alter class client change title default NULL

332. Schema management Index Client A customer name is unique. Add an index whose name is u_name. Title is in reverse order. Add an index whose name is idx1to sort customer names in forward direction. Searching table information by using a catalog Checking the information of a created table Table name, column information, index information create unique index u_name on client(client_name) create index idx1 on client(title desc, client_name) select * from db_class select * from db_attribute where class_name = 'client' select * from db_index where class_name = 'client'

333. Data search and manipulation Insertingdata Insert (10,’company10’), (20,’company20’) into the company table. Insert an arbitrary id,name, and the company ID whose comp_id is 20 into a client table in the insert-select format. Check inserteddata information by selecting rows from the client table. insert into company values (10, 'company10'); insert into company values (10, 'company10'),(20, 'company20'); insert into company (comp_id, comp_name) values (20, 'company20'); insert into client (comp_id, client_id, client_name) select comp_id, 20, 'new staff20'from company where comp_id = 20

334. Data search and manipulation Modifying data insert an arbitraryid and name into a client table. Check the inserted data information by searching for the client table. Change the comp_id to 10 for the data inserted in the client table. Check inserted data information by searching for the client table. insert into client (client_id, client_name) values (30, 'new staff30') update client set comp_id = 10 where client_id = 30

335. Data search and manipulation Data search Retrieve the countries that achieved medals in the 1988 Olympics from the participants and their medal information Table where participants are listed: participant Medal information table : game - Retrievemedal information of the participants in the 1988 Olympics select (select name from nation where code = a.nation_code), medal from participant a, game b where a.host_year = 1988 and a.nation_code = b.nation_code and a.host_year = b.host_year select (select name from nation where code = a.nation_code), medal from participant a left outer join game b on a.nation_code = b.nation_code and a.host_year = b.host_year where a.host_year = 1988

336. Data search and manipulation Usingindex Sorting the cities that have hosted the Olympics in chronological order Table in which the names of cities that have hosted the Olympics are listed: olympic Sorting the cities that have hosted the Olympics, so that the most recent ones appear at the front select host_year,host_nation,host_city from olympic where host_year > '' using index pk_olympic_host_year(+) create index r_year on olympic(host_yeardesc) select host_year, host_nation, host_city from olympic where host_year > '' using index r_year(+) order by host_yeardesc

338. Operators and functions Function Finding an arbitrary number between 1 and 100 Rounding 3.141592653 to the nearest millionth Finding out the number of bus stops where you can catch the No. 10 bus Length of the following string (‘substring xyzxxy’), position of ‘str’, extracting 6 characters from the 4th character, removing ‘xy’ from the string, replacing ‘s’ with ‘S’ select mod(rand(), 100) + 1 from db_root select round(3.141592653, 6), trunc(3.141592653, 6) from db_root select count(sation_id) from bus where bus_num = '10' select length('substring xyzxxy'), instr ('substring xyzxxy', 'str'), substr('substring xyzxxy', 4, 6), rtrim('substring xyzxxy', 'xy'), replace(('substring xyzxxy', 's', 'S')from db_root

339. Operators and functions For the Olympic medals, use 'G' for a 'gold medal,' 'S' for a 'silver medal,' and 'B' for a 'bronze medal.' Olympic medal table : game Use '1900s' for the Olympics held in the 1900s, '2000s' for 2000s, and 'Other' for other years, and calculate the number Olympics held. Table showing Olympics years: olympic select decode(medal, 'G'. 'gold medal', 'S', 'silver medal', 'B', 'bronze medal') from game select case when host_year between 1900 and 1999 then '1900s' when host_year between 2000 and 2999then '2000s' else 'other years'end as years, count(*) from olympic group by case when host_year between 1900 and 1999 then '1900s' when host_year between 2000 and 2999then '2000s' else 'other years'end

341. Modifying the above query using index hint

342. Grouping by host_nation columnselect * from olympic where rownum between 11 and 20 select * from olympic order by host_year for orderby_num() between 11 and 20; select * from olympic order by host_year limit 11, 20; select * from olympic where host_year > 0 and rownum between 11 and 20 using index pk_olympic_host_year(+) select host_nation from olympicwhere rownum between 11 and 20 group by host_nation

345. Insertdata to the autoincrement column

346. Insert no date to the auto increment column

347. Select rows and check the auto increment column values

348. Delete rows and re-insertdatacreate table bbs ( id intauto_increment, title string, cntint default 0 ) insert into bbs(id, title) values(5, 'arbitrary inserting for auto increment') insert into bbs(title) values('auto inserting for auto increment') select * from bbs delete from bbs insert into bbs(title) values('auto inserting for auto increment')