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When we use JOIN on one (self join) or more table inside a cursor declaration then a read-only cursor will be created. We cannot update the read-only cursor.If we want to update any of the tables used in the JOIN then we have to declare a separate cursor for all the tables and an individual logic has to be built in order to update each DB2 table.
Whenever we issue a COMMIT statement, all the open cursors will get closed. This is a very common case when we have to frequently use the commit statement after a UPDATE while working with a cursor. In this case we can use the “WITH HOLD” clause during the cursor declaration.The “WITH HOLD” clause will keep the cursor open even after firing the COMMIT statement. We can give the “WITH HOLD” clause in the following way.EXEC SQL DECLARE ORDER_CUR CURSOR WITH HOLD FOR SELECT ORDER_ID, TRANSACTION_ID FROM ORDERS WHERE ORDER_DATE = ‘2020-07-28’ END-EXEC
The “WHERE CURRENT OF” clause will place the exclusive lock on the row once the UPDATE statement is executed. The “WHERE CURRENT OF” clause will point to the most recently fetched row of the cursor.We can update the rows in cursor using “WHERE CURRENT OF” in the following way.CURSOR definition.EXEC SQL DECLARE ORDER_CUR CURSOR FOR SELECT ORDER_ID, TRANSACTION_ID FROM ORDERS WHERE ORDER_DATE = ‘2020-07-28’ END-EXECOPEN cursorEXEC SQL OPEN ORDER_CUR END-EXECFETCH cursor and Update rowSET WF-END-CURSOR-N TO TRUE PERFORM UNTIL WF-END-CURSOR-Y EXEC SQL FETCH ORDER_CUR INTO :ORDER-ID, :TRANSACTION-ID END-EXEC IF TRANSACTION-ID NOT = SPACES EXEC SQL ... Read More
We are required to write a JavaScript function that takes in two 2-D arrays of numbers and returns their matrix multiplication result.Let’s say the following are our two matrices −// 5 x 4 let a = [ [1, 2, 3, 1], [4, 5, 6, 1], [7, 8, 9, 1], [1, 1, 1, 1], [5, 7, 2, 6] ]; // 4 x 6 let b = [ [1, 4, 7, 3, 4, 6], [2, 5, 8, 7, 3, 2], [3, 6, 9, 6, 7, 8], [1, 1, 1, 2, 3, 6] ];ExampleLet’s ... Read More
We are required to write a JavaScript function that takes in a string and constructs a new string with all the uppercase characters converted to lowercase and all the lowercase characters converted to uppercase.Let’s write the code for this function −ExampleFollowing is the code −const str = 'The Case OF tHis StrinG Will Be FLiPped'; const isUpperCase = char => char.charCodeAt(0) >= 65 && char.charCodeAt(0) char.charCodeAt(0) >= 97 && char.charCodeAt(0) { let newStr = ''; const margin = 32; for(let i = 0; i < str.length; i++){ const curr = str[i]; ... Read More
The “FOR UPDATE OF” clause is given in the cursor declaration and it is used when we want to update the table. All the columns which need to be updated should be given in the cursor declaration.The “FOR UPDATE OF” clause will place the exclusive lock on all the qualifying rows once the cursor is open. We can also update the table without using “FOR UPDATE CLAUSE” but in that case the exclusive lock will be placed on the row only when the UPDATE query will be executed.
We are required to write a JavaScript function that takes in a number and returns an array of all the prime numbers that exactly divide the input number.For example, if the input number is 18.Then the output should be −const output = [2, 3];ExampleLet’s write the code for this function −const num = 18; const isPrime = (n) => { for(let i = 2; i { const res = num % 2 === 0 ? [2] : []; let start = 3; while(start
We are required to write a JavaScript function that takes in a string and returns a new string with all the character of the original string just the whitespaces removed.ExampleLet’s write the code for this function −const str = "This is an example string from which all whitespaces will be removed"; const removeWhitespaces = str => { let newStr = ''; for(let i = 0; i < str.length; i++){ if(str[i] !== " "){ newStr += str[i]; }else{ newStr += ''; }; }; return newStr; }; console.log(removeWhitespaces(str));OutputThe output in the console after removing whitespaces −Thisisanexamplestringfromwhichallwhitespaceswillberemoved
We are required to write a JavaScript function that takes in an array of numbers and uses the quick sort algorithm to sort it.QuickSortThis algorithm is basically a divide and conquer algorithm where we pick a pivot in every pass of loop and put all the elements smaller than pivot to its left and all greater than pivot to its right (if its ascending sort otherwise opposite)ExampleLet’s write the code for this function −const arr = [43, 3, 34, 34, 23, 232, 3434, 4, 23, 2, 54, 6, 54]; // Find a "pivot" element in the array to compare all ... Read More
In the English language, all these characters are considered as punctuations −'!', "," ,"\'" ,";" ,"\"", ".", "-" ,"?"We are required to write a JavaScript function that takes in a string and count the number of appearances of these punctuations in the string and return that count.ExampleLet’s write the code for this function −const str = "This, is a-sentence;.Is this a sentence?"; const countPunctuation = str => { const punct = "!,\;\.-?"; let count = 0; for(let i = 0; i < str.length; i++){ if(!punct.includes(str[i])){ continue; }; count++; }; return count; }; console.log(countPunctuation(str));OutputThe output in the console: −5