Manage Herbicide Imbalanced Join Conditions in Database Queries

RDBMS or Relational Database Management Systems use queries to fetch data from the database. Queries can be constructed on more than one table using equi or non equi joins. Queries can also specify where conditions, where data will be retrieved as per some conditions such as Select student_name from students where place_of_residence = “Chennai”. Join conditions are specified as Select a.customer_name, b.order_id from customer a, order b where a.customer_id = b.customer_id.In the above case a join is being made between two tables customer and order. Prior to a query being executed the SQL engine computes an execution plan. The query execution plan is a sequence of steps determined by the query optimizer. These steps would yield a sequence of operations which would result in the lowest cost of executing the query. In complex situations when queries are constructed between many tables specifying many query conditions one or two missed join conditions can lead to prolonged query run times if the database has high volumes of data.


A join of two tables without a join condition is just a cross product of two sets. If Table A has 10,000 rows and Table B has 5000 rows a cross product of two tables will result in 5,00,00,000 records. Whereas if a join condition is introduced the result set will contain 10,000 rows or 5,000 rows in the resultant search space. If a query for example contains 10 tables and cross products of two or three tables taken at a time, and if the query expression contains 20 – 30 joins 3 or 4 join conditions can be missed out due to negligence or error. This can be the case in case of SQL queries running in large manufacturing or production outlets doing heavy volume data processing. The size of each table is very large and so are the number of tables.A designer may compose a query to record an Actualization process in a production house in which actual sales data against projections are uploaded into the database. Due to the complexity of the database a single query may use 20 tables holding more than 100000 records per table on the average. The query may use a lot of joins and if due an accident some join conditions get skipped then the query would search in a space of 10 power 20 records instead of just 10 power 5 records. This would lead to prolonged query execution time sometimes a single program containing any such erroneous query can run for even 20 hours without completing the updations. But on identifying and adding missed join conditions such as table3.column3 = table4.column7 or table7.column2 = table1.column9 etc., into the query the query can be made to run in acceptable time.

Choosing Merchant Providers

If you are running a new business, then you may have a very hard time choosing a provider of merchant services. There are some things that can help in the determination of which is the best credit card processor. There are very many options that are available in the market today and this means that you have to be even more careful. It is important to select processors that can focus on some factors that are relevant to the company you are running.

The fee

The fees charged can actually increase as time goes by. A provider that allows for the negotiation of the percentage is the best. It is also important that all pricing differences are well understood and all variables such as credit card types, the value of the dollar and volume should also be laid out. Fees and should also be understood and they vary in accordance with variables.

The cash flow

This is yet another thing to consider. The credit card processors are responsible for holding the cash from processing time up until the time you get it in your account. It is important to appreciate the fact that different processors use different systems and they can manage time so as to earn some interest. When you choose a merchant provider that offers payment wallet, then you can gain access to the funds immediately. Sometimes the fees of companies aren’t as competitive as what independent providers offer.

Some of the questions that you should ask before choosing the merchant account

· Customer support: this is important because you may need some technical support from time to time. A good merchant service provider will allow you access to customer support 24/7. This will guarantee that issues will be addressed as soon as they arise.

· Live support: this has become very popular in the present times. Some of the companies have email support, but sometimes when you have a problem, you may want to talk to someone in real time.

· Time the company has been in operation: a provider that has a track record that is proven can really help. This is because the team has been able to build a reputation and specialized in the field.

· Offline and online transactions: as the business expands, do not keep on switching the merchants because they lack some of the services. It is essential to work with a merchant who will be able to help the retail business go online or offline.

· Fraud protection: ask the merchant about the ways they use so as to protect financial data because it is very sensitive.

· Funds processing time: it is important to have a predictable cash flow if you want business to prosper. You therefore need a provider who can tell you clearly how long it will take to clear the funds. This helps you avoid any surprises that can derail the operation of the business.

· Length of contract: this should also be put into consideration. For starters, a shorter contract is always better. You build on trust on the way and start looking at longer options.