Structured Query Language is a language for the databases. It is used to communicate with the databases to store and retrieve specific information from the databases.
Databases have information that other computers and applications require from time to time, and to retrieve that information, they need a language to communicate with the database management system, and the language used for the communication is known as SQL.
We will learn about SQL, how it works, how data is stored in the databases for SQL to access it, what is invalid column name error, and how to fix it.
HOW DOES SQL WORK?
The database has all the information stored in them. When a user requests information, SQL acts as the mediator between the user and the database to find and retrieve the required information from the database.
SQL finds the relevant information by communicating with the database and bringing it to the user in the presentable format.
To store, delete, update, and find the data in the database, SQL uses statements divided into different categories.
CATEGORIES OF SQL STATEMENTS
SQL use statements to perform the tasks it is assigned; there are four main categories of SQL statements:
DATA MANIPULATION LANGUAGE (DML)
There are six main statements in data manipulation language (DML) that are:
- Update (to update an already present value in the table)
- Select (to select a particular record from the table)
- Insert (to add a certain value in the database)
- Delete (to delete some record from the database)
- Lock (to lock a particular component of a database to read or write)
- Merge (to merge two rows of a table)
DATA DEFINITION LANGUAGE (DDL)
Data Definition Language (DDL) has five main SQL statements:
- Alter (to add, drop, rename, modify a column or to rename a table)
- Create (to create a new table in a database)
- Truncate (to delete specific data in the table of a database)
- Drop (to drop a specific table from the database)
- Rename (to rename the database or the table)
DATA CONTROL LANGUAGE (DCL)
DCL controls the data present in the database. Two types of statements are used in this category of statements:
- Grant (to provide access to database data to the user)
- Revoke (to disallow the user from accessing the data present in the database)
TRANSACTION CONTROL LANGUAGE (TCL)
TCL language manages transactions of the database and manages the changes made through the DML statements. TCL uses the five statements to perform its functions:
- Roll Back (to undo the changes made to the data in the database)
- Commit (to save the changes made to the database)
- Savepoint (to save the data temporarily only)
HOW IS DATA STORED IN DATABASE FOR SQL TO ACCESS IT
We are talking about a large amount of data, so to make it easily accessible, tables are used to store data. Database tables have rows and columns known as records and fields, respectively. A common error is known as “Invalid Column Name” often occurs in the database.
WHAT IS “INVALID COLUMN NAME ERROR”?
When you want to retrieve data from the database, you send a query that SQL uses to access a particular table and then the column and rows of that table to find the data you requested the SQL to find. But an error is shown at some times that states “Invalid Column Name.”
Let’s see what causes this error to occur.
CAUSE FOR “INVALID COLUMN NAME ERROR”
This error can be caused by many things that include:
- The name of the column you entered is not available in the database.
- You have misspelled the column name due to which SQL could not find the column.
- The column is not present in the table.
- You might be adding values with a double apostrophe.
HOW TO FIX “INVALID COLUMN NAME” ERROR
- Try correcting the spelling of the column you want to access.
- Try adding values with a single apostrophe.
- Try Assigning a different table to the column.
- Try using another name for the column that might be present in the database.
SQL is a language used for accessing the data present in the database by the user to get the desired information. SQL use different statements to perform its functions. Data is stored in tables with columns and rows to add, delete, and update the database’s data. We hope by using the methods we explained, you can resolve the invalid column name error.