Just face the harsh facts. Nobody loves SQL programming for the fun of it. You learn it to develop database applications the right way. It is your bread and butter. You want to make a living out of it. Before you build a database, you require one. Then, did you know that many projects are skewed even before the first line of the application is programmed properly? As a coder, you should first get the application right. If you goof up, your project will be doomed forever. That will affect your abilities as a programmer and SQL professional. So what are you supposed to do? Naturally, you want a solution, right. Fret not. Here are five SQL programming mistakes that a DBA professional must avoid:
1. Data Redundancy
As far as data redundancy is concerned, it is fine for backups but does not work when you are working on table data. Every table must include an exclusive or one of a kind data set, and this information should not repeat in other table locations. It is one of the most challenging ideas for any SQL coder to follow. You can forget the rules of normalization easily and end up repeating data across many tables for coding convenience. Such a practice shows your unprofessionalism. In fact, it shows bad table design.
Let us take an example to explain this point. You have a customer table that includes his address, which is related to the customer. Now, the address is at the right location. You design an ‘Order’ table, integrating the address in that table. It is poor design. You can link the customer and order table using relationships across foreign and primary keys. When you forget to update the address in the table, you will find two addresses for the customer, not knowing which of them is accurate. Therefore, ensure that you keep data in a single location, using relationships between primary and foreign keys. It will help you query the data.
2. Not Including Primary Keys
As a coder, you know this basic fact that each table needs a primary key to work. If you do not include it in any table, your coding fails to observe the typical SQL programming requirements. It leads to application performance issues. Primary keys are unique. Therefore, always utilize an auto-increasing numeric value if you do have any other column in the table, which meets the SQL coding guidelines. Therefore, if you want to build relational databases, including the primary key is mandatory. They connect with foreign keys in relational tables. For example, if there is a table with a customer list, the ‘customer ID’ is one such column that is a unique number for every consumer. It could be your primary key column. The customer value would be found in the ‘Order’ table to connect the two tables without any difficulty. Therefore, the moral of the story is creating a primary key for each table, irrespective of its size. If you want to know more about SQL programming, study online resources, books, or platforms like RemoteDBA.com.
3. Thinking That Your Client Knows His Requirements
When you get an SQL programming project from your client, what happens? Your customer asks you to build a database system. Your clients have issues related to the information they require, as they may not have their current techniques up and running. They feel that they know all about the problem and its possible resolution. They assume that their job is telling you how to work on the database system. If you presume so, you are highly mistaken too.
Remember many of your clients may not know or possess the required knowledge or skill sets to identify a specific SQL coding issue. Therefore, they cannot recommend the best solution when you are programming. Make sure that you persuade your clients that you have the required experience in database design and systems analysis. Therefore, you need some time to analyze the problem to get to the root of the issue. You need to do this very diplomatically without annoying your clients or making them feel ignorant.
4. Looping with Multiple Cursors
As far as the looping structures in SQL programming are concerned, they’re considered as a nuisance. Though it may allow coders to loop via numerous records and run statements against one another independently, it may affect the performance of a database considerably. Loops are used in coding, but not for SQL programming. If you loop multiple cursors, database admins will discard your SQL procedures that have cursors employed.
Learn to write procedures following a different approach. It will help you to avoid database performance issues. You can substitute cursors with a well-written SQL statement. In case, you cannot avoid their use, ensure that they stick to listed tasks that function during off-peak hours. If you need to use cursors for data transformation or for reporting queries, you cannot avoid them completely. What you need to do is limiting their use in production databases that work on daily queries against a database.
5. Forgetting Indexing
A knowledgeable and experienced SQL programmer knows how to index a table impeccably. As a coder, you should benefit from these performance improvements. You need to use the JOIN statement on columns allocated to a particular index. When it comes to the primary key column, it is nothing but an index. Therefore, there is no need to fuss over performance or efficiency concerning that. Make sure that the foreign key has an index too. No matter what JOIN statements you use, it should include a set of index on the column. If you detect that an index is missing, integrate one to the table. It will lead to stellar database performance.
Avoiding these common mistakes will help you build SQL databases that your clients will love. You will be in the good books of your customers, get more projects, and earn money. If you want to build relational databases, you should learn how to create the perfect SQL statement and improve queries and tables for optimal performance. Learn to avoid these mistakes and implement the right programming rules. It will help you build a fast and efficient database for any business – be it small, medium, or a large corporation.
Author Bio: Jonathan Smith is a seasoned SQL programmer and associated with RemoteDBA.com for many years now. He has the coding rules on his fingertips. He has a penchant for churning out technical articles for aspiring coders. His hobbies include sports and reading technical journals online.