When a client application wants to carry out a database task, such retrieving information or inserting a new row into a table, it does so using Structured Query Language (SQL) statements. SQL is pronounced “sequel”.
Depending how a client application is developed, SQL statements could be supplied in function calls from the programming language, or you may build them graphically in a special window provided by the application development tool.
The programming interface delivers the SQL statement to the database server. The database server receives the statement and executes it, returning any required information (such as query results) back to the application.
Client/server communication protocols carry information between the client application and the database server. Programming interfaces define how an application sends the information. No matter what interface and network protocol you use, it is SQL statements that are sent to a server, and the results of SQL statements that are returned to the client application.
