a)
Transaction:
A transaction is a logical unit of work.
- A sequence of process that must be completely completed or aborted.
- Intermediate states are not acceptable in the process of transaction.
- To make a transaction use a keyword “BEGIN TRANSACTION;”, insert SQL queries and commit the transaction.
Syntax for “TRANSACTION”:
BEGIN {TRANSACTION|TRAN};
SQL queries;
COMMIT;
“insert” query:
The INSERT command in SQL is employed to add records to an existing table. INSERT will increase the number of rows in a table.
Syntax for INSERT command:
INSERT INTO table_name VALUES (value1, value2…);
Example:
INSERT INTO employee VALUES(101, ‘Smith’,10);
“update” query:
The UPDATE command is employed to update information present in a table.
It is always used with SET keyword either in bulk or individually. UPDATE will not increase the number of rows in a table.
Syntax for UPDATE command:
UPDATE table_name SET column_name1 = value WHERE some_condition;
Example:
UPDATE employee SET name= ‘Presil’ age= 24 WHERE id=115;
b)
Explanation of Solution
Program plan:
The following SQL query is to make a customer payment for a customer “10010” of “$100” in cash using the payment ID “3428”.
- Begin the transaction.
- Insert the appropriate values into “payments” table using “insert” query.
- Update the customer details to reduce the customer balance by “100” for the customer “10010” using “update” query...
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Chapter 10 Solutions
Database Systems: Design Implementation & Management
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- Need with explanationarrow_forwardThe relational schema shown below is part of a hospital database. The primary keys are highlighted in bold. Patient (patientNo, patName, patAddr, DOB)Ward (wardNo, wardName, wardType, noOfBeds)Contains (patientNo, wardNo, admissionDate)Drug (drugNo, drugName, costPerUnit)Prescribed (patientNo, drugNo, unitsPerDay, startDate, finishDate) Formulate the following SQL statements: a) Find the names of all the patients being prescribed ‘Morphine’.b) What is the total cost of Morphine supplied to a patient called ‘John Smith’?c) For each ward that admitted more than 10 patients today, list the ward number, ward type and number of beds in each ward.arrow_forwardTHIS IS A PROBLEM IN MYSQL. PLEASE ANSWER CORRECTLY. OUR MY SQL IS RUN USING COMMAND LINEarrow_forward
- Explainarrow_forwardER Mapping : Convert the ER diagram into a relational database schema. For each relation, specify the primary keys and the foreign key(s) if any (50 pts) Upload you Relational Diagram here BANK BRANCHES BANK-BRANCH Code Name Addr Addr BranchNo АССTS LOANS N AcctNo Balance LoanNo Amount ACCOUNT Туре LOAN Type M M A-C L-C N Name N. SSN Phone CUSTOMER Addrarrow_forwardWrite the following queries in SQL on the relational database schema for COMPANY database given in page 4. Find the last name of the supervisors who do not have dependents.arrow_forward
- Database Systems: Design, Implementation, & Manag...Computer ScienceISBN:9781305627482Author:Carlos Coronel, Steven MorrisPublisher:Cengage LearningDatabase Systems: Design, Implementation, & Manag...Computer ScienceISBN:9781285196145Author:Steven, Steven Morris, Carlos Coronel, Carlos, Coronel, Carlos; Morris, Carlos Coronel and Steven Morris, Carlos Coronel; Steven Morris, Steven Morris; Carlos CoronelPublisher:Cengage LearningA Guide to SQLComputer ScienceISBN:9781111527273Author:Philip J. PrattPublisher:Course Technology Ptr