Learn how to use the TRUNCATE command to clear a table from all of its rows and the differences between TRUNCATE and DELETE.
- [Instructor] Previously in our chapter,…we learned about Oracle DDL commands.…DDL commands, or data definition language command,…allows us to create new database objects…such as creating new tables,…but they also allow us to modify the structure of…existing database objects such as…adding new columns to our tables.…So let's see an example DDL command…where we will add a new column to our table.…I can accomplish that by typing, alter table,…the table name, test_table1, in my case,…add, and then inside brackets,…the column name and column data types.…
So for example col3 and a data type…of number with a precision of 10.…So this command, alter table, test_table1,…which is the name of the table, add,…and then inside brackets the column name, col3, in our case,…and the column data type, number with a precision of 10.…So this command will add col3 to our table.…Let's run the command, we see that the database…notified us that the table has been indeed altered,…and let's select data from our table.…
So select * from test_table1…
Author
David Yahalom
Released
1/17/2018Note: This training course is appropriate for beginning database developers with no prior experience with SQL or Oracle.
- Using Oracle SQL*Developer, the free development environment
- Selecting data from tables
- Filtering data
- Using functions to manipulate data
- Joining data from tables
- Creating tables
- Updating values
- Truncating data
- Grouping and ordering result sets
- Working with primary keys
- Checking constraints
Skill Level Beginner
Duration
Views
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Introduction
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Welcome1m 37s
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1. Introduction to SQL
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What is SQL?2m 30s
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Database tables2m 21s
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Overview of table data types4m 21s
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SQL query structure4m 38s
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2. Preparing the Course Environment
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Downloading the course VM2m 16s
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3. Using Oracle SQL Developer
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Exploring database objects1m 29s
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Filtering specific objects1m 25s
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Using SQL Developer tabs2m 18s
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Viewing query output1m 18s
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4. Basic SELECT Queries
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Using WHERE to filter dates2m 42s
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Using column aliases2m 18s
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Using ORDER BY3m 29s
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5. String, Number, and Date Functions
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Introduction to functions1m 39s
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Using LENGTH1m 4s
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Using CONCAT4m 48s
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Using LOWER and UPPER2m 44s
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Using INSTR4m 32s
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Using RPAD and LPAD3m 31s
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Using ROUND1m 15s
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Using TRUNC1m 36s
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Using SYSDATE1m 59s
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Using SYSTIMESTAMP1m 37s
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Using MONTHS_BETWEEN3m 2s
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Using ADD_MONTHS1m 17s
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6. Joining Table Data
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Joining data from tables4m 12s
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INNER JOIN1m 17s
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LEFT JOIN2m 55s
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RIGHT JOIN1m 55s
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FULL OUTER JOIN1m 59s
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7. Manipulating Data
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Creating a simple table2m 1s
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COMMIT and ROLLBACK2m 23s
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Introduction to transactions3m 43s
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Deleting rows for a table3m 23s
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Updating values2m 40s
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8. Grouping Data
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Using aggregate functions2m 24s
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Using GROUP BY2m 45s
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Using HAVING3m
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9. Advanced Topics
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Primary keys2m 47s
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NOT NULL constraints1m 36s
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Check constraints3m 2s
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Foreign key constraints6m 4s
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Subqueries4m 39s
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Conclusion
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Next steps1m 33s
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Video: Adding and dropping columns from a table