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A compression is used to save the DB2 disk space. The compression can be used either at row level or at a page level. In order to add a row compression in a DB2 table, we can give the following command−ALTER TABLE DBSET1.TAB1 COMPRESS YES STATICWe have to use ALTER TABLE for the compression of the DB2 table. The ALTER TABLE reserved words are followed by the name of DB2 table qualified by database. COMPRESS YES STATIC will complete the row compression for the said table.
A DB2 collection is a physical quantity which is used to group the packages. A collection can be simply termed as a group of DB2 packages. By using collections we can bind the same DBRM into different packages. In order to delete all the DB2 packers under a collection, we can issue below command.FREE PACKAGE(COLL1.*)The FREE PACKAGE reserved word is followed by the name of collection i.e. COLL1. The * after the collection name indicates that we need to perform delete action for all the packages under the said collection.
We can delete the unused tables in the DB2. However, we must keep in mind that if we delete a table then all the indexes associated with the table are also dropped. Moreover, the triggers and views for the deleted table will become inaccessible. To delete any table in DB2, we can issue below command.DROP TABLE DBSET1.TAB1The DROP TABLE reserved word will be followed by the name of the table qualified by the database. The mentioned table will be deleted from the DB2 permanently.
DB2 gives us an option of modifying the attribute of the existing column in a table. We have to use the ALTER COLUMN parameter with ALTER TABLE as below in order to achieve this.ALTER TABLE DBSET1.TAB1 ALTER COLUMN NAME SET DATATYPE CHAR(50);The ALTER TABLE reserved words are followed by the name of the table qualified by a database, which is DBSET1.TAB1 in this case. Similarly, ALTER COLUMN is followed by the name of the column which needs to be modified, which NAME (of the student) in this case.In the SET DATATYPE parameter, we can pass the ... Read More
DB2 gives us an option to copy the structure of an existing table to a new table. To copy the attributes and column of table TAB1 to a new table TAB2 we can use the following command−CREATE TABLE DBSET1.TAB2 LIKE DBSET1.TAB1The CREATE TABLE reserved words are followed by table name. The table name needs to be qualified by a database in which it will reside. In this case this new table is TAB2 and its database is DBSET1.The LIKE parameter is used after that followed by the name of the original table qualified by its database i.e. DBSET1.TAB1The important ... Read More
A view is an alternative way of representing the data stored in a table. A view can be used to increase the performance of the query since the view contains very limited rows as compared to its source table. We can use the below command to create a view on an existing table TAB1.CREATE VIEW AGEVIEW (NAME, AGE, ENROLLMENT_ID) AS SELECT NAME, AGE, ENROLLMENT_ID FROM TAB1 WHERE AGE > 10;We have to use CREATE VIEW reserved words in order to create a new view. This will be followed by the name of the view (AGEVIEW).The columns ... Read More
A foreign key is a column in a table that establishes a referential link with another table. A foreign key can be defined during creation of table (CREATE TABLE command) or it can be defined by modifying the table (ALTER TABLE command). However, before defining any key as foreign key, make sure that an index is built up on that column. We can use the below command to define an existing column CLASS in table TAB1 as a foriegn key which links to table TAB2.ALTER TABLE TAB1 ADD FOREIGN KEY (CLASS) REFERENCES CLASSDATA (CLASS_ID);The ALTER TABLE reserved words are followed ... Read More
Let’s say the following is our list −var details=[ {id:101, name:"John", age:21}, {id:111, name:"David", age:24}, {id:1, name:"Mike", age:22}, {id:"", name:"Sam", age:20}, {id: 1, name:"Carol", age:23}, {id:null, name:"Robert", age:25}, {id:1, name:"Adam", age:24}, {id:"", name:"Chris", age:23} ];You can use the concept of filter to retrieve values based on specific ID.Examplevar details=[ {id:101, name:"John", age:21}, {id:111, name:"David", age:24}, {id:1, name:"Mike", age:22}, {id:"", name:"Sam", age:20}, {id: 1, name:"Carol", age:23}, {id:null, name:"Robert", age:25}, {id:1, name:"Adam", age:24}, {id:"", name:"Chris", age:23} ]; var getIdWithValue1 = details.filter(obj => obj.id === 1); console.log(getIdWithValue1);To ... Read More
Let’s say the following are our coordinates −var listOfStrings = ["10.45322, -6.8766363", "78.93664664, -9.74646646", "7888.7664664, -10.64664632"];To convert the above into two float lists of Latitude and Longitude, use split() on the basis of comma(, ) along with map().Examplevar listOfStrings = ["10.45322, -6.8766363", "78.93664664, -9.74646646", "7888.7664664, -10.64664632"]; var latitude = []; var longitude = []; listOfStrings.forEach(obj => obj.split(', ') .map(Number) .forEach((value, index) => [latitude, longitude][index].push(value)) ); console.log("All positive value is latitude=") console.log(latitude); console.log("All negative value is longitude=") console.log(longitude);To run the above program, you need to use the following command −node fileName.js.Here, my file name is demo180.js.OutputThis will produce the following output ... Read More
To ignore a specific value, use the logical Not (!) operator in if condition and fetch watching you want to include.Examplevar customerDetails=[ { customerName:"John", customerAge:28, customerCountryName:"US" }, { customerName:"David", customerAge:25, customerCountryName:"AUS" }, { customerName:"Mike", customerAge:32, customerCountryName:"UK" } ] for(var i=0;i node demo179.js The country name is=US The country name is=UK