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+# H2
+
+<web-summary>
+Use Kotlin DataFrame to query H2 databases via JDBC — read tables, run SQL queries, or fetch result sets directly.
+</web-summary>
+
+<card-summary>
+Connect to H2 databases in Kotlin DataFrame and load data using simple JDBC configurations.
+</card-summary>
+
+<link-summary>
+Read from H2 databases in Kotlin DataFrame using built-in SQL reading methods.
+</link-summary>
+
+
+Kotlin DataFrame supports reading from an [H2](https://www.h2database.com/html/main.html) database using JDBC.
+
+Requires the [`dataframe-jdbc` module](Modules.md#dataframe-jdbc),
+which is included by default in the general [`dataframe` artifact](Modules.md#dataframe-general)
+and in [`%use dataframe`](SetupKotlinNotebook.md#integrate-kotlin-dataframe) for Kotlin Notebook.
+
+You’ll also need [the official H2 JDBC driver](https://www.h2database.com/html/main.html):
+
+<tabs>
+<tab title="Gradle project">
+
+```kotlin
+dependencies {
+    implementation("com.h2database:h2:$version")
+}
+```
+
+</tab>
+<tab title="Kotlin Notebook">
+
+
+```kotlin
+USE {
+    dependencies("com.h2database:h2:$version")
+}
+```
+
+</tab>
+</tabs>
+
+The actual Maven Central driver version could be found
+[here](https://mvnrepository.com/artifact/com.h2database/h2).
+
+## Read
+
+[`DataFrame`](DataFrame.md) can be loaded from a database in several ways:  
+a user can read data from a SQL table by given name ([`readSqlTable`](readSqlDatabases.md)),  
+as a result of a user-defined SQL query ([`readSqlQuery`](readSqlDatabases.md)),  
+or from a given `ResultSet` ([`readResultSet`](readSqlDatabases.md)).  
+It is also possible to load all data from non-system tables, each into a separate `DataFrame` ([`readAllSqlTables`](readSqlDatabases.md)).
+
+See [](readSqlDatabases.md) for more details.
+
+### H2 Compatibility Modes
+
+When working with H2 database, the library automatically detects the compatibility mode from the connection.
+If no `MODE` is specified in the JDBC URL, the default `Regular` mode is used.
+H2 supports the following compatibility modes: `MySQL`, `PostgreSQL`, `MSSQLServer`, `MariaDB`, and `Regular`.
+
+```kotlin
+import org.jetbrains.kotlinx.dataframe.io.DbConnectionConfig
+import org.jetbrains.kotlinx.dataframe.api.*
+
+// Basic H2 connection (uses Regular mode by default)
+
+val url = "jdbc:h2:mem:testDatabase"
+val username = "sa"
+val password = ""
+
+val dbConfig = DbConnectionConfig(url, username, password)
+
+val tableName = "Customer"
+
+val df = DataFrame.readSqlTable(dbConfig, tableName)
+```
+
+```kotlin
+import org.jetbrains.kotlinx.dataframe.io.DbConnectionConfig
+import org.jetbrains.kotlinx.dataframe.api.*
+
+// H2 with PostgreSQL compatibility mode
+
+val postgresUrl = "jdbc:h2:mem:testDatabase;MODE=PostgreSQL"
+val username = "sa"
+val password = ""
+
+val postgresConfig = DbConnectionConfig(postgresUrl, username, password)
+
+val tableName = "Customer"
+
+val dfPostgres = DataFrame.readSqlTable(postgresConfig, tableName)
+```
+