diff --git a/README.md b/README.md
index 5eb0c34..8d661c0 100644
--- a/README.md
+++ b/README.md
@@ -63,7 +63,7 @@ public class DLockConfig {
     public KeyLock keyLock(DataSource dataSource) {
         return new JDBCKeyLockBuilder()
                 .dataSource(dataSource)
-                .databaseType(DatabaseType.H2) // or ORACLE
+                .databaseType(DatabaseType.H2) // or ORACLE, POSTGRESQL
                 .createDatabase(true) // Automatically creates the DLCK table
                 .build();
     }
@@ -199,7 +199,7 @@ When using the `KeyLock` API, keep the following constraints in mind:
 
 * [**dlock-api**](./dlock-api): Core interfaces (`KeyLock`, `LockHandle`).
 * [**dlock-core**](./dlock-core): Base implementation logic (expiration policies, utilities).
-* [**dlock-jdbc**](./dlock-jdbc): JDBC implementation (H2, Oracle support).
+* [**dlock-jdbc**](./dlock-jdbc): JDBC implementation (H2, Oracle, PostgreSQL support).
 * [**dlock-spring**](./dlock-spring): Spring integration (`@Lock` aspect).
 
 ```mermaid
diff --git a/dlock-jdbc/src/main/java/com/dlock/jdbc/builder/JDBCKeyLockBuilder.java b/dlock-jdbc/src/main/java/com/dlock/jdbc/builder/JDBCKeyLockBuilder.java
index 52be632..aed5080 100644
--- a/dlock-jdbc/src/main/java/com/dlock/jdbc/builder/JDBCKeyLockBuilder.java
+++ b/dlock-jdbc/src/main/java/com/dlock/jdbc/builder/JDBCKeyLockBuilder.java
@@ -42,6 +42,9 @@ public JDBCKeyLockBuilder databaseType(DatabaseType databaseType) {
     }
 
     public JDBCKeyLockBuilder lockTableName(String lockTableName) {
+        if (lockTableName == null || !lockTableName.matches("^[a-zA-Z0-9_]+$")) {
+            throw new IllegalArgumentException("Table name must only contain alphanumeric characters and underscores");
+        }
         this.lockTableName = lockTableName;
         return this;
     }
diff --git a/dlock-jdbc/src/main/java/com/dlock/jdbc/repository/JDBCLockRepository.java b/dlock-jdbc/src/main/java/com/dlock/jdbc/repository/JDBCLockRepository.java
index 894f1df..3ddade7 100644
--- a/dlock-jdbc/src/main/java/com/dlock/jdbc/repository/JDBCLockRepository.java
+++ b/dlock-jdbc/src/main/java/com/dlock/jdbc/repository/JDBCLockRepository.java
@@ -26,6 +26,7 @@ public class JDBCLockRepository implements LockRepository {
     private final String findByHandleSQL;
     private final String findByKeySQL;
     private final String removeByHandleSQL;
+    private final int insertParamsCount;
 
     public JDBCLockRepository(ScriptResolver scriptResolver, DataSource dataSource) {
         this.dataSource = dataSource;
@@ -33,6 +34,7 @@ public JDBCLockRepository(ScriptResolver scriptResolver, DataSource dataSource)
         this.findByHandleSQL = scriptResolver.resolveScript("lock.findByHandle");
         this.findByKeySQL = scriptResolver.resolveScript("lock.findByKey");
         this.removeByHandleSQL = scriptResolver.resolveScript("lock.removeByHandle");
+        this.insertParamsCount = countOccurrences(insertSQL, '?');
     }
 
     @Override
@@ -134,12 +136,19 @@ private boolean executeInsert(Connection connection, WriteLockRecord lockRecord)
             ps.setString(2, lockRecord.lockHandleId());
 
             ps.setLong(3, lockRecord.expirationSeconds());
-            ps.setString(4, lockRecord.lockKey());
+
+            if (insertParamsCount == 4) {
+                ps.setString(4, lockRecord.lockKey());
+            }
 
             return ps.executeUpdate() == 1;
         }
     }
 
+    private int countOccurrences(String str, char ch) {
+        return (int) str.chars().filter(c -> c == ch).count();
+    }
+
     /** Delete SQL PreparedStatement. */
     private boolean executeRemove(Connection connection, String lockHandleId) throws SQLException {
         try (PreparedStatement ps = connection.prepareStatement(removeByHandleSQL)) {
diff --git a/dlock-jdbc/src/main/resources/db/POSTGRESQL-sql.properties b/dlock-jdbc/src/main/resources/db/POSTGRESQL-sql.properties
index c710636..4f83d8d 100644
--- a/dlock-jdbc/src/main/resources/db/POSTGRESQL-sql.properties
+++ b/dlock-jdbc/src/main/resources/db/POSTGRESQL-sql.properties
@@ -1,4 +1,4 @@
-lock.findByKey=SELECT "LCK_KEY", "LCK_HNDL_ID", "CREATED_TIME", "EXPIRE_SEC", CURRENT_TIMESTAMP FROM "@@tableName@@" WHERE "LCK_KEY" = ?
-lock.findByHandle=SELECT "LCK_KEY", "LCK_HNDL_ID", "CREATED_TIME", "EXPIRE_SEC", CURRENT_TIMESTAMP FROM "@@tableName@@" WHERE "LCK_HNDL_ID" = ?
-lock.insert=INSERT INTO "@@tableName@@" ("LCK_KEY", "LCK_HNDL_ID", "CREATED_TIME", "EXPIRE_SEC") SELECT ?, ?, CURRENT_TIMESTAMP, ? WHERE NOT EXISTS (SELECT 1 FROM "@@tableName@@" WHERE "LCK_KEY" = ?)
-lock.removeByHandle=DELETE FROM "@@tableName@@" WHERE "LCK_HNDL_ID" = ?
+lock.findByKey=SELECT "LCK_KEY", "LCK_HNDL_ID", "CREATED_TIME", "EXPIRE_SEC", CURRENT_TIMESTAMP FROM "@@tableName@@" WHERE "LCK_KEY" = ?
+lock.findByHandle=SELECT "LCK_KEY", "LCK_HNDL_ID", "CREATED_TIME", "EXPIRE_SEC", CURRENT_TIMESTAMP FROM "@@tableName@@" WHERE "LCK_HNDL_ID" = ?
+lock.insert=INSERT INTO "@@tableName@@" ("LCK_KEY", "LCK_HNDL_ID", "CREATED_TIME", "EXPIRE_SEC") VALUES (?, ?, CURRENT_TIMESTAMP, ?) ON CONFLICT ("LCK_KEY") DO NOTHING
+lock.removeByHandle=DELETE FROM "@@tableName@@" WHERE "LCK_HNDL_ID" = ?
diff --git a/dlock-jdbc/src/test/groovy/com/dlock/jdbc/builder/JDBCKeyLockBuilderTest.groovy b/dlock-jdbc/src/test/groovy/com/dlock/jdbc/builder/JDBCKeyLockBuilderTest.groovy
new file mode 100644
index 0000000..7e30818
--- /dev/null
+++ b/dlock-jdbc/src/test/groovy/com/dlock/jdbc/builder/JDBCKeyLockBuilderTest.groovy
@@ -0,0 +1,48 @@
+package com.dlock.jdbc.builder
+
+import spock.lang.Specification
+import spock.lang.Unroll
+
+class JDBCKeyLockBuilderTest extends Specification {
+
+    @Unroll
+    def "should accept valid lockTableName: #tableName"() {
+        given:
+        def builder = new JDBCKeyLockBuilder()
+
+        when:
+        builder.lockTableName(tableName)
+
+        then:
+        noExceptionThrown()
+
+        where:
+        tableName << ["DLCK", "MyTable_1", "My_Table"]
+    }
+
+    @Unroll
+    def "should reject invalid lockTableName: #tableName"() {
+        given:
+        def builder = new JDBCKeyLockBuilder()
+
+        when:
+        builder.lockTableName(tableName)
+
+        then:
+        thrown(IllegalArgumentException)
+
+        where:
+        tableName << ["My-Table", "My.Table", "My Table", "DROP TABLE", ""]
+    }
+
+    def "should reject null lockTableName"() {
+        given:
+        def builder = new JDBCKeyLockBuilder()
+
+        when:
+        builder.lockTableName(null)
+
+        then:
+        thrown(IllegalArgumentException)
+    }
+}
diff --git a/dlock-spring/README.md b/dlock-spring/README.md
index 551291d..05c8e73 100644
--- a/dlock-spring/README.md
+++ b/dlock-spring/README.md
@@ -24,7 +24,7 @@ public class DLockConfig {
     public KeyLock keyLock(DataSource dataSource) {
         return new JDBCKeyLockBuilder()
                 .dataSource(dataSource)
-                .databaseType(DatabaseType.H2)
+                .databaseType(DatabaseType.H2) // or POSTGRESQL, ORACLE
                 .build();
     }
 }