what is data sechema in magento2 code example

Example: declarative schema in magento 2

<?xml version="1.0"?>
<schema xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:noNamespaceSchemaLocation="urn:magento:framework:Setup/Declaration/Schema/etc/schema.xsd">
    <table name="inchoo_declarative_schema1" resource="default" engine="innodb" comment="Inchoo Table 1">
        <column xsi:type="int" name="table_1_id" padding="10" unsigned="true" nullable="false" identity="true" comment="ID"/>
        <column xsi:type="varchar" name="name" comment="Name"/>
        <constraint xsi:type="primary" referenceId="PRIMARY">
            <column name="table_1_id"/>
        </constraint>
    </table>
    <table name="inchoo_declarative_schema2" resource="default" engine="innodb" comment="Inchoo Table 2">
        <column xsi:type="int" name="table_2_id" padding="10" unsigned="true" nullable="false" identity="true" comment="ID"/>
        <column xsi:type="text" name="content" comment="Content"/>
        <constraint xsi:type="primary" referenceId="PRIMARY">
            <column name="table_2_id"/>
        </constraint>
    </table>
</schema>