Term
| What are the four Column Constraints? |
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Definition
PRIMARY KEY constraint can be used to uniquely identify the row.
UNIQUE columns have a different value for every row.
NOT NULL columns must have a value.
DEFAULT assigns a default value for the column when no value is specified. |
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Term
| What is CREATE TABLE used for? |
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Definition
| The CREATE TABLE statement creates a new table in a database. It allows one to specify the name of the table and the name of each column in the table. |
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Term
| What is the syntax for CREATE TABLE? |
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Definition
CREATE TABLE table_name (
column1 datatype,
column2 datatype,
column3 datatype
); |
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Term
| What is the INSERT INTO statement used for? |
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Definition
The INSERT INTO statement is used to add a new record (row) to a table.
It has two forms:
Insert into columns in order.
Insert into columns by name. |
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Term
| What is the syntax for INSERT INTO? |
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Definition
-- Insert into columns in order:
INSERT INTO table_name
VALUES (value1, value2);
-- Insert into columns by name:
INSERT INTO table_name (column1, column2)
VALUES (value1, value2); |
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Term
| What is ALTER TABLE used for? |
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Definition
| The ALTER TABLE statement is used to modify the columns of an existing table. When combined with the ADD COLUMN clause, it is used to add a new column. |
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Term
| What is the syntax of ALTER TABLE? |
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Definition
ALTER TABLE table_name
ADD column_name datatype; |
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Term
| What is a DELETE FROM statement used for? |
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Definition
| The DELETE statement is used to delete records (rows) in a table. The WHERE clause specifies which record or records that should be deleted. If the WHERE clause is omitted, all records will be deleted. |
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Term
| What is the syntax of the DELETE FROM statement? |
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Definition
DELETE FROM table_name
WHERE some_column = some_value; |
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Term
| What is an UPDATE statement used for? |
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Definition
| The UPDATE statement is used to edit records (rows) in a table. It includes a SET clause that indicates the column to edit and a WHERE clause for specifying the record(s). |
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Term
| What is the syntax for the UPDATE statement? |
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Definition
UPDATE table_name
SET column1 = value1, column2 = value2
WHERE some_column = some_value; |
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