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10 Most Important SQL Skills for the Software Tester

Today, many products and web components suffer from such a common “disease” as maximum susceptibility to SQL injections. You can get a third-party access to certain parts of the encoded information within the database with its help.

This is eloquently evidenced by the fact that understanding the languages of SQL queries is the most important and fundamental condition for building an effective security assessment during software testing services.

Description of the SQL testing area features

Any testing specialist must fully understand certain materials before sitting down for the process of testing the database for a web vulnerability. These materials are the following:

  • Be able to search information on one table (from a simple condition to the most complex, interaction with operators, special aggregate functions, and subqueries);
  • Be able to search information on several tables (from a simple condition to the most complex, interaction with operators, special aggregate functions, and subqueries);
  • Modify the data: insert new values, update existing data and delete unnecessary parameters or values.

We can give the following notation when describing SQL in short. This is the classic language for entering the database system and performing certain operations in them according to set by the American National Standards Institute criteria.

This language is used not during the creation of certain web products but during the software components testing. Thus, testers are constantly faced with various databases during the mobile utility or banking program performance testing.

So, what are the 10 most important SQL skills for testers?

  • Executing created queries;
  • Data selecting;
  • Specific data inserting;
  • Database updating;
  • Deleting information from the database;
  • Creating a new table category;
  • Development a SQL table template;
  • Creating a demonstration environment in the database;
  • Migration of the database information block;
  • Checking the database security.

Let’s consider each element separately.

Processing and execution of SQL queries

First, you need to understand what exactly happens when you run the created query for the execution process in order for your query to have maximum efficiency and expediency.

To begin with, it can be noted that parsing is conducting and a query syntax tree is building in a system. The query is created primarily in order to understand how it corresponds to the semantics and syntactic features of a particular environment. You can get a general idea of the incoming request with the help of the parser. Then these data are passed to the program code handler.

The entire sequence of query execution can be described by such a hierarchical structure:

  • The original SQL expression;
  • Syntactic parsing;
  • The build process;
  • Optimization of the created query;
  • Executing the query;
  • Analysis of query results.

Pic01

Data selecting

A special the “SELECT” command is used to obtain a specific data sample. It has a simplified form of syntax and is denoted as follows:

Pic03
Wethinkitis clear that we should indicate the name of the column of interest to us, the parameters of which are interesting to analyze instead of the words “what to choose”. The name of our table is instead of “where to choose”.

For example, we want to see all the columns from the “USERS” table:

Pic04This is a full information about the data that you previously entered into this table.

Specific data inserting

To achieve the goal of information placement, you should refer to the “INSERT” command, which allows you to place the necessary values inside the table, namely:

  • Add 1 line;
  • Add part of the line;
  • Add the results of the SQL query.

In general, to perform the process of adding a new line to an existing table, you must specify its name, list the name of the available columns and give the value for each column with the “INSERT INTO” command – the table name, the “VALUE” command – the value.

Example:

Pic05
Database updating

Use the special “UPDATE” command to change the existing lines of the database. It is distinguished by such a formal syntax:
Pic06Forexample, youwant to check the logic of increasing the good price by 5000.
Pic07
Hereitisimportant to speak about the fact that the value change in the table is extremely rare for all positions. Often, you need to edit just one record. To do this, the command is supplemented with a WHERE directive inside which a certain condition is specified, according to which the system “understands” which line to perform a certain operational action.

In practice, it looks like this:

Pic08

Deleting information

All without exception, manipulations to delete information in the database are performed based on the configuration of the “DELETE” statement.

You can quickly remove lines from temporary or permanent table forms using it. It has such a lowercase index:

Pic09

Allthelinesfrom the table are deleted if there is no the “DELETE” statement. A similar command is performed using the “TRUNCATE TABLE” command + the name of the required table.

If even a number of features, according to which the use of the second command in comparison with the principle of the “DELETE” command, is less productive.

And that’s why:

  • The process of logging deleted lines is not performed. The log contains exclusively exempt pages that were previously busy by other tables;
  • Triggers are not reproduced, namely a deleting trigger;
  • TRUNCATE TABLE will not be executed if the external link is connected to the table by a special key;
  • The “IDENTITY” counter parameters are reset to the initial values.

Creating a new table category

Adding a new table is done using the “SELECT INTO” statement.

This command is used very often in cases when it is necessary to combine several tables into one complete structure, calculate general data and conduct a certain information analysis.

The “SELECT INTO” command has several arguments:

  • NEW_TABLE – the name of the table;
  • FILEGROUP is a generalized filegroup. The default filegroup is applied if no argument is specified.

Development a new SQL table template

It is necessary to use the “CREATE TABLE” statement to create a new table.

Here the basic syntax of this construct is as follows:

Pic10

The “CREATE TABLE” command is the most important when checking the overall state of the database because it is very difficult to verify the performance.

It is necessary to think up the original name of the table or its ID to create a new table correctly after the given statement.

Example of a finished table:

Pic11

Now this table can be easily tested.

Creating a demonstration environment in the database

As a rule, a special “FILESTREAM” file group is used for this type of purposes.

The process of creating a database with support for the expansion of the “FILESTREAM” group looks like this:

  • A new request is created, through which the user has a personalized access to the query editor in a specialized SQL Server management Studio environment;
  • Then you need to copy Transact-SQL with FILESTREAM support, called Archive.

As a result, there should be such a demonstration environment which fully satisfies the requests for further testing.

Migration of the database information block

There are situations when it is necessary to test not only the database efficiency and its level of security but the introduction of new properties into its structure. Similar actions, according to which the structure is updated, is called migration.

For example, we have a classic “USER” model

Pic12

In addition, a special context of information is provided, through which the user interacts with the database:

Pic13

So we decided to make certain changes to the model database of the utility. For example, we want to add one more user to the “USER” model:

Pic14

We need a special “VISUAL STUDIO – PACKAGE MANAGER CONSOLE” component for migration, where it is necessary to register the command.

After this, the migration process will be performed exclusively in automatic order.

In conclusion, it is worth noting that there is nothing complicated when interacting with real scenarios when you need to run the overall operation of a certain database and also check the vulnerability to external threats.

A small set of basic knowledge is enough for software test outsourcing and any tester is able to conduct a comprehensive assessment of the overall performance of any database based on a special programming SQL language in the shortest time.

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