In this tutorial, we have shown you how to use the SQLite REPLACE statement to insert or replace a row in a table. If the title column does not have the NOT NULL constraint, the REPLACE statement will insert a new row whose the title column is NULL. Therefore, SQLite rolls back the transaction. However, it violates the NOT NULL constraint of the title column. Then, SQLite tried to insert a new row with two columns: ( id, min_salary). What the statement tried to do is to update the min_salary for the position with id 2, which is the developer.įirst, the position with id 2 already exists, the REPLACE statement removes it. VALUES( 2, 110000) Code language: SQL (Structured Query Language) ( sql ) Notice that the REPLACE statement means INSERT or REPLACE, not INSERT or UPDATE. Third, SQLite inserted a new row with the data provided by the REPLACE statement. Second, because this statement violated the UNIQUE constraint by trying to add the DBA title that already exists, SQLite deleted the existing row. REPLACE INTO positions (title, min_salary)Ĭode language: SQL (Structured Query Language) ( sql )įirst, SQLite checked the UNIQUE constraint. In the second step, if any constraint violation e.g., NOT NULL constraint occurs, the REPLACE statement will abort the action and. Positions Code language: SQL (Structured Query Language) ( sql ) The idea of the REPLACE statement is that when a UNIQUE or PRIMARY KEY constraint violation occurs, it does the following: First, delete the existing row that causes a constraint violation. You can verify the REPLACE operation using the SELECT statement. VALUES( 'Full Stack Developer', 140000) Code language: SQL (Structured Query Language) ( sql ) REPLACE INTO positions (title, min_salary) The following REPLACE statement inserts a new row into the positions table because the position title Full Stack Developer is not in the positions table. Suppose, you want to add a position into the positions table if it does not exist, in case the position exists, update the current one. ON positions (title) Code language: SQL (Structured Query Language) ( sql ) The following statement creates a unique index on the title column of the positions table to ensure that it doesn’t have any duplicate position title: CREATE UNIQUE INDEX idx_positions_title SELECT * FROM positions Code language: SQL (Structured Query Language) ( sql ) Third, verify the insert using the following SELECT statement. ( 'Architect', 150000) Code language: SQL (Structured Query Language) ( sql ) INSERT INTO positions (title, min_salary) Second, insert some rows into the positions table. ) Code language: SQL (Structured Query Language) ( sql ) The SQLite REPLACE statement examplesįirst, create a new table named positions with the following structure. Let’s take a look at some examples of using the SQLite REPLACE statement to understand how it works. Or in a short form: REPLACE INTO table(column_list) VALUES(value_list) Code language: SQL (Structured Query Language) ( sql ) INSERT OR REPLACE INTO table(column_list) The following illustrates the syntax of the REPLACE statement. In the second step, if any constraint violation e.g., NOT NULL constraint occurs, the REPLACE statement will abort the action and roll back the transaction. First, delete the existing row that causes a constraint violation.The idea of the REPLACE statement is that when a UNIQUE or PRIMARY KEY constraint violation occurs, it does the following: In order to import data into an SQLite database, it must be in a suitable format. Introduction to the SQLite REPLACE statement loop through the result set while (rs.Summary: in this tutorial, you will learn how to use the SQLite REPLACE statement to insert or replace the existing row in a table. String sql = "SELECT id, name, capacity FROM warehouses" * select all rows in the warehouses table String url = "jdbc:sqlite:C://sqlite/db/test.db" The following program selects all rows from the warehouses table. Finally, use the get* method of the ResultSet object such as getInt(), getString(), getDouble(), etc., to get the data in each iteration.After that, loop through the result set using the next() method of the ResultSet object.The executeQuery() method accepts a SELECT statement. Then, create an instance of the ResultSet class by calling the executeQuery method of the Statement object.Next, create an instance of the Statement class from the Connection object.First, create a Connection object to connect to the SQLite database. To query data from a table, you use the following steps: Summary: in this tutorial, you will learn how to query data from a table in the SQLite database using Java JDBC.
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