diff options
Diffstat (limited to 'doc/src/sgml/html/dml-insert.html')
-rw-r--r-- | doc/src/sgml/html/dml-insert.html | 81 |
1 files changed, 81 insertions, 0 deletions
diff --git a/doc/src/sgml/html/dml-insert.html b/doc/src/sgml/html/dml-insert.html new file mode 100644 index 0000000..5182205 --- /dev/null +++ b/doc/src/sgml/html/dml-insert.html @@ -0,0 +1,81 @@ +<?xml version="1.0" encoding="UTF-8" standalone="no"?> +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>6.1. Inserting Data</title><link rel="stylesheet" type="text/css" href="stylesheet.css" /><link rev="made" href="pgsql-docs@lists.postgresql.org" /><meta name="generator" content="DocBook XSL Stylesheets Vsnapshot" /><link rel="prev" href="dml.html" title="Chapter 6. Data Manipulation" /><link rel="next" href="dml-update.html" title="6.2. Updating Data" /></head><body id="docContent" class="container-fluid col-10"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="5" align="center">6.1. Inserting Data</th></tr><tr><td width="10%" align="left"><a accesskey="p" href="dml.html" title="Chapter 6. Data Manipulation">Prev</a> </td><td width="10%" align="left"><a accesskey="u" href="dml.html" title="Chapter 6. Data Manipulation">Up</a></td><th width="60%" align="center">Chapter 6. Data Manipulation</th><td width="10%" align="right"><a accesskey="h" href="index.html" title="PostgreSQL 15.4 Documentation">Home</a></td><td width="10%" align="right"> <a accesskey="n" href="dml-update.html" title="6.2. Updating Data">Next</a></td></tr></table><hr /></div><div class="sect1" id="DML-INSERT"><div class="titlepage"><div><div><h2 class="title" style="clear: both">6.1. Inserting Data</h2></div></div></div><a id="id-1.5.5.3.2" class="indexterm"></a><a id="id-1.5.5.3.3" class="indexterm"></a><p> + When a table is created, it contains no data. The first thing to + do before a database can be of much use is to insert data. Data is + inserted one row at a time. You can also insert more than one row + in a single command, but it is not possible to insert something that + is not a complete row. Even if you know only some column values, a + complete row must be created. + </p><p> + To create a new row, use the <a class="xref" href="sql-insert.html" title="INSERT"><span class="refentrytitle">INSERT</span></a> + command. The command requires the + table name and column values. For + example, consider the products table from <a class="xref" href="ddl.html" title="Chapter 5. Data Definition">Chapter 5</a>: +</p><pre class="programlisting"> +CREATE TABLE products ( + product_no integer, + name text, + price numeric +); +</pre><p> + An example command to insert a row would be: +</p><pre class="programlisting"> +INSERT INTO products VALUES (1, 'Cheese', 9.99); +</pre><p> + The data values are listed in the order in which the columns appear + in the table, separated by commas. Usually, the data values will + be literals (constants), but scalar expressions are also allowed. + </p><p> + The above syntax has the drawback that you need to know the order + of the columns in the table. To avoid this you can also list the + columns explicitly. For example, both of the following commands + have the same effect as the one above: +</p><pre class="programlisting"> +INSERT INTO products (product_no, name, price) VALUES (1, 'Cheese', 9.99); +INSERT INTO products (name, price, product_no) VALUES ('Cheese', 9.99, 1); +</pre><p> + Many users consider it good practice to always list the column + names. + </p><p> + If you don't have values for all the columns, you can omit some of + them. In that case, the columns will be filled with their default + values. For example: +</p><pre class="programlisting"> +INSERT INTO products (product_no, name) VALUES (1, 'Cheese'); +INSERT INTO products VALUES (1, 'Cheese'); +</pre><p> + The second form is a <span class="productname">PostgreSQL</span> + extension. It fills the columns from the left with as many values + as are given, and the rest will be defaulted. + </p><p> + For clarity, you can also request default values explicitly, for + individual columns or for the entire row: +</p><pre class="programlisting"> +INSERT INTO products (product_no, name, price) VALUES (1, 'Cheese', DEFAULT); +INSERT INTO products DEFAULT VALUES; +</pre><p> + </p><p> + You can insert multiple rows in a single command: +</p><pre class="programlisting"> +INSERT INTO products (product_no, name, price) VALUES + (1, 'Cheese', 9.99), + (2, 'Bread', 1.99), + (3, 'Milk', 2.99); +</pre><p> + </p><p> + It is also possible to insert the result of a query (which might be no + rows, one row, or many rows): +</p><pre class="programlisting"> +INSERT INTO products (product_no, name, price) + SELECT product_no, name, price FROM new_products + WHERE release_date = 'today'; +</pre><p> + This provides the full power of the SQL query mechanism (<a class="xref" href="queries.html" title="Chapter 7. Queries">Chapter 7</a>) for computing the rows to be inserted. + </p><div class="tip"><h3 class="title">Tip</h3><p> + When inserting a lot of data at the same time, consider using + the <a class="xref" href="sql-copy.html" title="COPY"><span class="refentrytitle">COPY</span></a> command. + It is not as flexible as the <a class="xref" href="sql-insert.html" title="INSERT"><span class="refentrytitle">INSERT</span></a> + command, but is more efficient. Refer + to <a class="xref" href="populate.html" title="14.4. Populating a Database">Section 14.4</a> for more information on improving + bulk loading performance. + </p></div></div><div class="navfooter"><hr /><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="dml.html" title="Chapter 6. Data Manipulation">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="dml.html" title="Chapter 6. Data Manipulation">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="dml-update.html" title="6.2. Updating Data">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Chapter 6. Data Manipulation </td><td width="20%" align="center"><a accesskey="h" href="index.html" title="PostgreSQL 15.4 Documentation">Home</a></td><td width="40%" align="right" valign="top"> 6.2. Updating Data</td></tr></table></div></body></html>
\ No newline at end of file |