Java Tutorial/Database/MySQL
Содержание
- 1 Create a MySQL Table to Store Java Types (Using Statement Objects)?
- 2 Creating a Database in MySQL
- 3 Creating a MySQL Database Table to store Java Types
- 4 Creating a MySQL Table to Store Java Types
- 5 Deleting All Rows from a Database Table
- 6 Deleting a Table from Database
- 7 Exporting a MySQL Table to a Flat File
- 8 Get a MySQL Connection from the Driver Manager
- 9 Getting the Number of Rows in a Database Table
- 10 Inserting values in MySQL database table
- 11 JDBC Mysql Connection String
- 12 Keep the Connection Alive for MySQL
- 13 Loading a Flat File to a MySQL Table, file is comma-separated
- 14 Loading a Flat File to a MySQL Table, file is terminated by \r\n, use this statement
- 15 MySQL Connection Properties: Passing Additional Properties Using a Database URL
- 16 MySQL Data type to Java Data type Conversion Table
- 17 MySQL Error code and message
- 18 Retrieve auto-generated keys
- 19 Retrieve Automatically Generated Keys Using a Statement (MySQL)?
- 20 Retrieving Tables from a Database
- 21 Updating a Row in a Database Table
Create a MySQL Table to Store Java Types (Using Statement Objects)?
StringBuffer tableString = new StringBuffer("CREATE TABLE mysql_all_types(");
// Column Name MySQL Type Java Type
tableString.append("column_boolean BOOL, "); // boolean
tableString.append("column_byte TINYINT, "); // byte
tableString.append("column_short SMALLINT, " ); // short
tableString.append("column_int INTEGER, " ); // int
tableString.append("column_long BIGINT, " ); // long
tableString.append("column_float FLOAT, " ); // float
tableString.append("column_double DOUBLE PRECISION, "); // double
tableString.append("column_bigdecimal DECIMAL(13,0), " ); // BigDecimal
tableString.append("column_string VARCHAR(254), " ); // String
tableString.append("column_date DATE, " ); // Date
tableString.append("column_time TIME, " ); // Time
tableString.append("column_timestamp TIMESTAMP, " );// Timestamp
tableString.append("column_asciistream1 TINYTEXT, " ); // Clob (< 2^8 bytes)
tableString.append("column_asciistream2 TEXT, " ); // Clob (< 2^16 bytes)
tableString.append("column_asciistream3 MEDIUMTEXT, " ); // Clob (< 2^24 bytes)
tableString.append("column_asciistream4 LONGTEXT, " ); // Clob (< 2^32 bytes)
tableString.append("column_blob1 TINYBLOB, " ); // Blob (< 2^8 bytes)
tableString.append("column_blob2 BLOB, " ); // Blob (< 2^16 bytes)
tableString.append("column_blob3 MEDIUMBLOB, " ); // Blob (< 2^24 bytes)
tableString.append("column_blob4 LONGBLOB)" ); // Blob (< 2^32 bytes)
stmt.executeUpdate(tableString.toString());
//From Book: JDBC Recipes A Problem-Solution Approach
Creating a Database in MySQL
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.Statement;
public class Main {
public static void main(String[] argv) throws Exception {
Class.forName("com.mysql.jdbc.Driver");
Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/jdbctutorial", "root", "root");
Statement st = con.createStatement();
st.executeUpdate("CREATE DATABASE myDB");
}
}
Creating a MySQL Database Table to store Java Types
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.Statement;
public class Main {
public static void main(String[] argv) throws Exception {
String user = "root";
String pass = "root";
Class.forName("com.mysql.jdbc.Driver").newInstance();
Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/jdbctutorial", user, pass);
Statement st = con.createStatement();
String table = "CREATE TABLE java_DataTypes2(typ_boolean BOOL, "
+ "typ_byte TINYINT, typ_short SMALLINT, "
+ "typ_int INTEGER, typ_long BIGINT, "
+ "typ_float FLOAT, typ_double DOUBLE PRECISION, "
+ "typ_bigdecimal DECIMAL(13,0), typ_string VARCHAR(254), "
+ "typ_date DATE, typ_time TIME, " + "typ_timestamp TIMESTAMP, "
+ "typ_asciistream TEXT, typ_binarystream LONGBLOB, " + "typ_blob BLOB)";
st.executeUpdate(table);
con.close();
}
}
Creating a MySQL Table to Store Java Types
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.Statement;
public class Main {
public static void main(String[] argv) throws Exception {
String driverName = "com.jnetdirect.jsql.JSQLDriver";
Class.forName(driverName);
String serverName = "127.0.0.1";
String portNumber = "1433";
String mydatabase = serverName + ":" + portNumber;
String url = "jdbc:JSQLConnect://" + mydatabase;
String username = "username";
String password = "password";
Connection connection = DriverManager.getConnection(url, username, password);
Statement stmt = connection.createStatement();
String sql = "CREATE TABLE mysql_all_table("
+ "col_boolean BOOL, " // boolean
+ "col_byte TINYINT, " // byte
+ "col_short SMALLINT, " // short
+ "col_int INTEGER, " // int
+ "col_long BIGINT, " // long
+ "col_float FLOAT, " // float
+ "col_double DOUBLE PRECISION, " // double
+ "col_bigdecimal DECIMAL(13,0), " // BigDecimal
+ "col_string VARCHAR(254), " // String
+ "col_date DATE, " // Date
+ "col_time TIME, " // Time
+ "col_timestamp TIMESTAMP, " // Timestamp
+ "col_asciistream TEXT, " // AsciiStream (< 2^16 bytes)
+ "col_binarystream LONGBLOB, " // BinaryStream (< 2^32 bytes)
+ "col_blob BLOB)"; // Blob (< 2^16 bytes)
stmt.executeUpdate(sql);
}
}
Deleting All Rows from a Database Table
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.Statement;
public class Main {
public static void main(String[] argv) throws Exception {
String driverName = "com.jnetdirect.jsql.JSQLDriver";
Class.forName(driverName);
String serverName = "127.0.0.1";
String portNumber = "1433";
String mydatabase = serverName + ":" + portNumber;
String url = "jdbc:JSQLConnect://" + mydatabase;
String username = "username";
String password = "password";
Connection connection = DriverManager.getConnection(url, username, password);
Statement stmt = connection.createStatement();
// Use TRUNCATE
String sql = "TRUNCATE my_table";
// Execute deletion
stmt.executeUpdate(sql);
// Use DELETE
sql = "DELETE FROM my_table";
// Execute deletion
stmt.executeUpdate(sql);
}
}
Deleting a Table from Database
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.Statement;
public class Main {
public static void main(String[] argv) throws Exception {
String driverName = "com.mysql.jdbc.Driver";
String userName = "root";
String password = "root";
Class.forName(driverName).newInstance();
Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/jdbctutorial",
userName, password);
Statement st = con.createStatement();
st.executeUpdate("DROP TABLE Employee1");
con.close();
}
}
Exporting a MySQL Table to a Flat File
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.Statement;
public class Main {
public static void main(String[] argv) throws Exception {
String driverName = "org.gjt.mm.mysql.Driver";
Class.forName(driverName);
String serverName = "localhost";
String mydatabase = "mydatabase";
String url = "jdbc:mysql://" + serverName + "/" + mydatabase;
String username = "username";
String password = "password";
Connection connection = DriverManager.getConnection(url, username, password);
Statement stmt = connection.createStatement();
String filename = "c:/outfile.txt";
String tablename = "mysql_2_table";
stmt.executeUpdate("SELECT * INTO OUTFILE \"" + filename + "\" FROM " + tablename);
}
}
Get a MySQL Connection from the Driver Manager
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
public class Main {
public static void main(String[] args) throws Exception {
Connection conn = null;
conn = getConnection("jdbc:mysql://localhost/empDB", "root", "rootpass");
conn.close();
}
public static Connection getConnection(String dbURL, String user, String password)
throws SQLException, ClassNotFoundException {
Class.forName("com.mysql.jdbc.Driver");
return DriverManager.getConnection(dbURL, user, password);
}
}
Getting the Number of Rows in a Database Table
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
public class Main {
public static void main(String[] argv) throws Exception {
String driverName = "com.jnetdirect.jsql.JSQLDriver";
Class.forName(driverName);
String serverName = "127.0.0.1";
String portNumber = "1433";
String mydatabase = serverName + ":" + portNumber;
String url = "jdbc:JSQLConnect://" + mydatabase;
String username = "username";
String password = "password";
Connection connection = DriverManager.getConnection(url, username, password);
Statement stmt = connection.createStatement();
ResultSet resultSet = stmt.executeQuery("SELECT COUNT(*) FROM my_table");
// Get the number of rows from the result set
resultSet.next();
int rowcount = resultSet.getInt(1);
}
}
Inserting values in MySQL database table
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.Statement;
public class Main {
public static void main(String[] argv) throws Exception {
String driver = "com.mysql.jdbc.Driver";
Class.forName(driver);
Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/jdbctutorial", "root", "root");
Statement st = con.createStatement();
int val = st.executeUpdate("INSERT employee VALUES(" + 13 + "," + ""Aman"" + ")");
System.out.println("1 row affected");
}
}
JDBC Mysql Connection String
import java.sql.Connection;
import java.sql.DriverManager;
public class Main {
public static void main(String[] argv) throws Exception {
String driver = "com.mysql.jdbc.Driver";
String connection = "jdbc:mysql://localhost:3306/YourDBName";
String user = "root";
String password = "root";
Class.forName(driver);
Connection con = DriverManager.getConnection(connection, user, password);
if (!con.isClosed()) {
con.close();
}
}
}
Keep the Connection Alive for MySQL
public static final String DATABASE_USER = "user";
public static final String DATABASE_PASSWORD = "password";
public static final String MYSQL_AUTO_RECONNECT = "autoReconnect";
public static final String MYSQL_MAX_RECONNECTS = "maxReconnects";
public static Connection getConnection() throws Exception {
String driver = "org.gjt.mm.mysql.Driver";
Class.forName(driver);
String dbURL = "jdbc:mysql://localhost/tiger";
String dbUsername = "root";
String dbPassword = "root";
java.util.Properties connProperties = new java.util.Properties();
connProperties.put(DATABASE_USER, dbUsername);
connProperties.put(DATABASE_PASSWORD, dbPassword);
connProperties.put(MYSQL_AUTO_RECONNECT, "true");
connProperties.put(MYSQL_MAX_RECONNECTS, "4");
return DriverManager.getConnection(dbURL, connProperties);
}
Loading a Flat File to a MySQL Table, file is comma-separated
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.Statement;
public class Main {
public static void main(String[] argv) throws Exception {
Statement stmt = connection.createStatement();
// Load the data
String filename = "c:/infile.txt";
String tablename = "mysql_2_table";
stmt.executeUpdate("LOAD DATA INFILE \"" + filename + "\" INTO TABLE " + tablename);
// file is comma-separated
stmt.executeUpdate("LOAD DATA INFILE \"" + filename + "\" INTO TABLE "
+ tablename + " FIELDS TERMINATED BY ","");
}
}
Loading a Flat File to a MySQL Table, file is terminated by \r\n, use this statement
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.Statement;
public class Main {
public static void main(String[] argv) throws Exception {
Connection connection = DriverManager.getConnection(url, username, password);
Statement stmt = connection.createStatement();
// Load the data
String filename = "c:/infile.txt";
String tablename = "mysql_2_table";
stmt.executeUpdate("LOAD DATA INFILE \"" + filename + "\" INTO TABLE " + tablename);
// file is terminated by \r\n, use this statement
stmt.executeUpdate("LOAD DATA INFILE \"" + filename + "\" INTO TABLE "
+ tablename + " LINES TERMINATED BY "\\r\\n"");
}
}
MySQL Connection Properties: Passing Additional Properties Using a Database URL
//
// define and set connection properties using a database URL
//
String databaseURL = "jdbc:mysql://localhost/dbyour?user=root"+
"&password=rootp&useUnicode=true&characterEncoding=utf8";
MySQL Data type to Java Data type Conversion Table
MySQL Data Types Java Types
CHAR, VARCHAR, BLOB, TEXT, ENUM, and SET java.lang.String, java.io.InputStream,
java.io.Reader, java.sql.Blob, and java.sql.Clob
FLOAT, REAL, DOUBLE PRECISION, NUMERIC, java.lang.String, java.lang.Short, java.lang.Integer,
DECIMAL, TINYINT, SMALLINT, MEDIUMINT, java.lang.Long, java.lang.Double, and java.math.BigDecimal
INTEGER, and BIGINT
DATE, TIME, DATETIME, and TIMESTAMP java.lang.String, java.sql.Date, and java.sql.Timestamp
MySQL Error code and message
/*
Copyright (C) 2002 MySQL AB
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
import java.util.Hashtable;
/**
* SQLError is a utility class that maps MySQL error codes to X/Open
* error codes as is required by the JDBC spec.
*
* @author Mark Matthews <mmatthew_at_worldserver.ru>
* @version $Id: SQLError.java,v 1.2 2002/04/21 03:03:46 mark_matthews Exp $
*/
class SQLError {
//~ Instance/static variables .............................................
private static Hashtable mysqlToSqlState;
private static Hashtable sqlStateMessages;
//~ Initializers ..........................................................
static {
sqlStateMessages = new Hashtable();
sqlStateMessages.put("01002", "Disconnect error");
sqlStateMessages.put("01004", "Data truncated");
sqlStateMessages.put("01006", "Privilege not revoked");
sqlStateMessages.put("01S00", "Invalid connection string attribute");
sqlStateMessages.put("01S01", "Error in row");
sqlStateMessages.put("01S03", "No rows updated or deleted");
sqlStateMessages.put("01S04", "More than one row updated or deleted");
sqlStateMessages.put("07001", "Wrong number of parameters");
sqlStateMessages.put("08001", "Unable to connect to data source");
sqlStateMessages.put("08002", "Connection in use");
sqlStateMessages.put("08003", "Connection not open");
sqlStateMessages.put("08004", "Data source rejected establishment of connection");
sqlStateMessages.put("08007", "Connection failure during transaction");
sqlStateMessages.put("08S01", "Communication link failure");
sqlStateMessages.put("21S01", "Insert value list does not match column list");
sqlStateMessages.put("22003", "Numeric value out of range");
sqlStateMessages.put("22005", "Numeric value out of range");
sqlStateMessages.put("22008", "Datetime field overflow");
sqlStateMessages.put("22012", "Division by zero");
sqlStateMessages.put("28000", "Invalid authorization specification");
sqlStateMessages.put("42000", "Syntax error or access violation");
sqlStateMessages.put("S0001", "Base table or view already exists");
sqlStateMessages.put("S0002", "Base table not found");
sqlStateMessages.put("S0011", "Index already exists");
sqlStateMessages.put("S0012", "Index not found");
sqlStateMessages.put("S0021", "Column already exists");
sqlStateMessages.put("S0022", "Column not found");
sqlStateMessages.put("S0023", "No default for column");
sqlStateMessages.put("S1000", "General error");
sqlStateMessages.put("S1001", "Memory allocation failure");
sqlStateMessages.put("S1002", "Invalid column number");
sqlStateMessages.put("S1009", "Invalid argument value");
sqlStateMessages.put("S1C00", "Driver not capable");
sqlStateMessages.put("S1T00", "Timeout expired");
//
// Map MySQL error codes to X/Open error codes
//
mysqlToSqlState = new Hashtable();
//
// Communications Errors
//
// ER_BAD_HOST_ERROR 1042
// ER_HANDSHAKE_ERROR 1043
// ER_UNKNOWN_COM_ERROR 1047
// ER_IPSOCK_ERROR 1081
//
mysqlToSqlState.put(new Integer(1042), "08S01");
mysqlToSqlState.put(new Integer(1043), "08S01");
mysqlToSqlState.put(new Integer(1047), "08S01");
mysqlToSqlState.put(new Integer(1081), "08S01");
//
// Authentication Errors
//
// ER_ACCESS_DENIED_ERROR 1045
//
mysqlToSqlState.put(new Integer(1045), "28000");
//
// Resource errors
//
// ER_CANT_CREATE_FILE 1004
// ER_CANT_CREATE_TABLE 1005
// ER_CANT_LOCK 1015
// ER_DISK_FULL 1021
// ER_CON_COUNT_ERROR 1040
// ER_OUT_OF_RESOURCES 1041
//
// Out-of-memory errors
//
// ER_OUTOFMEMORY 1037
// ER_OUT_OF_SORTMEMORY 1038
//
mysqlToSqlState.put(new Integer(1037), "S1001");
mysqlToSqlState.put(new Integer(1038), "S1001");
//
// Syntax Errors
//
// ER_PARSE_ERROR 1064
// ER_EMPTY_QUERY 1065
//
mysqlToSqlState.put(new Integer(1064), "42000");
mysqlToSqlState.put(new Integer(1065), "42000");
//
// Invalid argument errors
//
// ER_WRONG_FIELD_WITH_GROUP 1055
// ER_WRONG_GROUP_FIELD 1056
// ER_WRONG_SUM_SELECT 1057
// ER_TOO_LONG_IDENT 1059
// ER_DUP_FIELDNAME 1060
// ER_DUP_KEYNAME 1061
// ER_DUP_ENTRY 1062
// ER_WRONG_FIELD_SPEC 1063
// ER_NONUNIQ_TABLE 1066
// ER_INVALID_DEFAULT 1067
// ER_MULTIPLE_PRI_KEY 1068
// ER_TOO_MANY_KEYS 1069
// ER_TOO_MANY_KEY_PARTS 1070
// ER_TOO_LONG_KEY 1071
// ER_KEY_COLUMN_DOES_NOT_EXIST 1072
// ER_BLOB_USED_AS_KEY 1073
// ER_TOO_BIG_FIELDLENGTH 1074
// ER_WRONG_AUTO_KEY 1075
// ER_NO_SUCH_INDEX 1082
// ER_WRONG_FIELD_TERMINATORS 1083
// ER_BLOBS_AND_NO_TERMINATED 1084
//
mysqlToSqlState.put(new Integer(1055), "S1009");
mysqlToSqlState.put(new Integer(1056), "S1009");
mysqlToSqlState.put(new Integer(1057), "S1009");
mysqlToSqlState.put(new Integer(1059), "S1009");
mysqlToSqlState.put(new Integer(1060), "S1009");
mysqlToSqlState.put(new Integer(1061), "S1009");
mysqlToSqlState.put(new Integer(1062), "S1009");
mysqlToSqlState.put(new Integer(1063), "S1009");
mysqlToSqlState.put(new Integer(1066), "S1009");
mysqlToSqlState.put(new Integer(1067), "S1009");
mysqlToSqlState.put(new Integer(1068), "S1009");
mysqlToSqlState.put(new Integer(1069), "S1009");
mysqlToSqlState.put(new Integer(1070), "S1009");
mysqlToSqlState.put(new Integer(1071), "S1009");
mysqlToSqlState.put(new Integer(1072), "S1009");
mysqlToSqlState.put(new Integer(1073), "S1009");
mysqlToSqlState.put(new Integer(1074), "S1009");
mysqlToSqlState.put(new Integer(1075), "S1009");
mysqlToSqlState.put(new Integer(1082), "S1009");
mysqlToSqlState.put(new Integer(1083), "S1009");
mysqlToSqlState.put(new Integer(1084), "S1009");
//
// ER_WRONG_VALUE_COUNT 1058
//
mysqlToSqlState.put(new Integer(1058), "21S01");
// ER_CANT_CREATE_DB 1006
// ER_DB_CREATE_EXISTS 1007
// ER_DB_DROP_EXISTS 1008
// ER_DB_DROP_DELETE 1009
// ER_DB_DROP_RMDIR 1010
// ER_CANT_DELETE_FILE 1011
// ER_CANT_FIND_SYSTEM_REC 1012
// ER_CANT_GET_STAT 1013
// ER_CANT_GET_WD 1014
// ER_UNEXPECTED_EOF 1039
// ER_CANT_OPEN_FILE 1016
// ER_FILE_NOT_FOUND 1017
// ER_CANT_READ_DIR 1018
// ER_CANT_SET_WD 1019
// ER_CHECKREAD 1020
// ER_DUP_KEY 1022
// ER_ERROR_ON_CLOSE 1023
// ER_ERROR_ON_READ 1024
// ER_ERROR_ON_RENAME 1025
// ER_ERROR_ON_WRITE 1026
// ER_FILE_USED 1027
// ER_FILSORT_ABORT 1028
// ER_FORM_NOT_FOUND 1029
// ER_GET_ERRNO 1030
// ER_ILLEGAL_HA 1031
// ER_KEY_NOT_FOUND 1032
// ER_NOT_FORM_FILE 1033
// ER_DBACCESS_DENIED_ERROR 1044
// ER_NO_DB_ERROR 1046
// ER_BAD_NULL_ERROR 1048
// ER_BAD_DB_ERROR 1049
// ER_TABLE_EXISTS_ERROR 1050
// ER_BAD_TABLE_ERROR 1051
// ER_NON_UNIQ_ERROR 1052
// ER_BAD_FIELD_ERROR 1054
mysqlToSqlState.put(new Integer(1054), "S0022");
// ER_TEXTFILE_NOT_READABLE 1085
// ER_FILE_EXISTS_ERROR 1086
// ER_LOAD_INFO 1087
// ER_ALTER_INFO 1088
// ER_WRONG_SUB_KEY 1089
// ER_CANT_REMOVE_ALL_FIELDS 1090
// ER_CANT_DROP_FIELD_OR_KEY 1091
// ER_INSERT_INFO 1092
// ER_INSERT_TABLE_USED 1093
}
//~ Methods ...............................................................
static String get(String stateCode) {
return (String) sqlStateMessages.get(stateCode);
}
/**
* Map MySQL error codes to X/Open error codes
*
* @param errno the MySQL error code
* @return the corresponding X/Open error code
*/
static String mysqlToXOpen(int errno) {
Integer err = new Integer(errno);
if (mysqlToSqlState.containsKey(err)) {
return (String) mysqlToSqlState.get(err);
} else {
return "S1000";
}
}
}
Retrieve auto-generated keys
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
public class Main {
private static final String URL = "jdbc:mysql://localhost/testdb";
private static final String USERNAME = "root";
private static final String PASSWORD = "";
public static void main(String[] args) throws Exception {
Class.forName("com.mysql.jdbc.Driver");
Connection conn = DriverManager.getConnection(URL, USERNAME, PASSWORD);
String insert = "INSERT INTO orders (username, order_date) VALUES ("foobar", "2007-12-13")";
Statement stmt = conn.createStatement();
stmt.executeUpdate(insert, Statement.RETURN_GENERATED_KEYS);
ResultSet keys = stmt.getGeneratedKeys();
int lastKey = 1;
while (keys.next()) {
lastKey = keys.getInt(1);
}
System.out.println("Last Key: " + lastKey);
conn.close();
}
}
Retrieve Automatically Generated Keys Using a Statement (MySQL)?
mysql> CREATE TABLE yourtable (
-> id INT NOT NULL AUTO_INCREMENT,
-> name VARCHAR(32) NOT NULL,
-> PRIMARY KEY (id)
-> );
Solution
stmt.executeUpdate("insert into yourtable (name) values("tiger")");
rs = stmt.getGeneratedKeys();
Retrieving Tables from a Database
import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.DriverManager;
import java.sql.ResultSet;
public class Main {
public static void main(String[] argv) throws Exception {
String driver = "com.mysql.jdbc.Driver";
String user = "root";
String pass = "root";
Class.forName(driver);
Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/jdbctutorial", user,
pass);
DatabaseMetaData dbm = con.getMetaData();
String[] types = { "TABLE" };
ResultSet rs = dbm.getTables(null, null, "%", types);
System.out.println("Table name:");
while (rs.next()) {
String table = rs.getString("TABLE_NAME");
System.out.println(table);
con.close();
}
}
}
Updating a Row in a Database Table
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.Statement;
public class Main {
public static void main(String[] argv) throws Exception {
String driverName = "com.jnetdirect.jsql.JSQLDriver";
Class.forName(driverName);
String serverName = "127.0.0.1";
String portNumber = "1433";
String mydatabase = serverName + ":" + portNumber;
String url = "jdbc:JSQLConnect://" + mydatabase;
String username = "username";
String password = "password";
Connection connection = DriverManager.getConnection(url, username, password);
Statement stmt = connection.createStatement();
String sql = "UPDATE my_table SET col_string="a new string" WHERE col_string = "a string"";
int updateCount = stmt.executeUpdate(sql);
}
}
