Posts Tagged ‘SQL’
Writing SQL statement with Loop Objects
Written by techieDan on March 15, 2008 – 12:19 amCoding have never been the same!!! Some bad habits when writing codes which are redundant
String[] special = {"a1","a2","a3","a4"};
Connection con = null;
PreparedStatement stmt = null;
PreparedStatement stmt2 = null;
ResultSet rs = null;
ResultSet rs2 = null;
Class.forName ("com.mysql.jdbc.Driver")
conn = DriverManager.getConnection (url, userName, password);
String SQL_QUERY = " SELECT count(*) FROM tblABC WHERE " +
" name_tennis LIKE = ? ";
String SQL_QUERY2 = " SELECT count(*) FROM tblABC WHERE " +
" name_swimwear LIKE = ? ";
stmt = con.prepareStatement(SQL_QUERY);
stmt2 = con.prepareStatement(SQL_QUERY2);
for (int i=0;i<special[i].length;i++) {
stmt.setString(1,special[i]);
rs = stmt.executeQuery();
if (rs.next()) {
/* More work here */
}
}
for (int i=0;i i<special[i].length;i++) {
stmt2.setString(1,special[i]);
rs2 = stmt2.executeQuery();
if (rs2.next()) {
/* More work here */
}
}
The above is a very bad example of coding. It might work, and run smoothly but it’s really bad coding. What one should do is to not to let the code be redundant. For example, put both statements into one the loop.
for (int i=0;i<special[i].length;i++) {
stmt.setString(1,special[i]);
rs = stmt.executeQuery();
if (rs.next()) {
/* More work here */
} stmt2.setString(1,special[i]);
rs2 = stmt2.executeQuery();
if (rs2.next()) {
/* More work here */
}
}
What’s the use of this? Well, iif you have an object or rather a Bean to set into, you don’t have to loop and reloop. All can be done in the same loop. Well, hope this brings about some bad habits of coding java.
Tags: code, java, SQL
Posted in SQL, java | No Comments »
mySQL msSQL syntax
Written by techieDan on February 13, 2008 – 12:39 ammySQL and msSQL has a similar SQL syntax but not the same. To have a grasp of what does this mean, let’s have an exercise to get 10 rows from a table with mySQL.
select * from [tablename] limit 10
Now if you were to run this sql query above on msSQL server you’ll either get a wrong sql query or query not able to compute. So alternative for msSQL is by entering this query instead.
select top 10 * from [tablename]
Simple?? Yes, that’s all there is to it. To those that need further questions answered, there are bound to be helpful people posting or me trying to help people out.
Tags: mssql, mysql, SQL
Posted in SQL | No Comments »
