DATA MANIPULATION LANGUAGE
You’ll use DML statements to insert, update, and delete data in a database. The common state-ments include INSERT, UPDATE, and DELETE, as shown in Table 2-8.
TABLE 2-8 DML statements
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Figure 2-7 shows an example of a DML INSERT statement used to add a new record into the Students table. The new student has a StudentID of 1, a FirstName of John, and a LastName of Doe.
FIGURE 2-7 DML INSERT statement
Figure 2-8 shows the UPDATE statement used to update the Students table by changing the FirstName to Jane for the student with a StudentID of 1.
FIGURE 2-8 DML UPDATE statement
Figure 2-9 shows the DELETE statement used to remove records from the Students table where the StudentID is 1.
FIGURE 2-9 DML DELETE statement
Although technically part of the Data Query Language, SELECT is often considered part of DML as it is fundamental to manipulating data. The SELECT statement is used to fetch data from a database.
Figure 2-10 shows the SELECT statement fetching all the data from the Students table for the record where StudentID is 1.
FIGURE 2-10 DML SELECT statement
Figure 2-11 shows how to merge data from UpdatedStudents (based on StudentID) and insert new records from UpdatedStudents into Students.
38 CHAPTER 2 Identify considerations for relational data on Azure
FIGURE 2-11 DML MERGE statement
Mastering the DML statements is crucial for effective database operations and data management. Make sure to practice these commands with different tables and databases to thoroughly understand how they work.